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Barr Al Hikman

Shorebird paradise in Oman

‫جيم دي فو‬ ‫رويالند بوم‬ ‫وارد هاجميجير‬ ‫أندرو ثورب‬ ‫ريمون كالسين‬ ‫تصوير جان فان دي كام‬

Jimmy de Fouw Roeland Bom Ward Hagemeijer Andrew Thorpe Raymond Klaassen

Photography Jan van de Kam


2


Foreword by Mohammed bin Salem Al-Tobi Minister of Environment and Climate Affairs Protecting the environment, conserving its natural resources and preserving

which has a number of unique natural components. It contains a range of

its natural and biological diversity, is of utmost importance. Due to the rich

islands, marshes, mangroves, coral reefs, nesting and feeding sites of marine

biodiversity and habitat diversity of the Sultanate, the Ministry of

turtles, and feeding and breeding sites of marine mammals, including the

Environment and Climate Affairs is declaring its natural reserves and

rare Arabian Sea humpback whale, which is under threat of extinction.

detailing its rich biodiversity, ecosystems, and services. The Sultanate of

In order to raise awareness and knowledge of the unique diversity of the

Oman has declared the Wetlands Reserve in Al Wusta Governorate by the

reserve, the Ministry has participated in preparing and publishing this book,

Royal Decree No. 51/2014. This reserve is especially important due to its

the first of its kind in the Sultanate, which focuses on a particular nature

unique natural and geological components. It is a critical habitat and one of

reserve and its regional and global importance for migratory shorebirds.

the most important protected sites in the Sultanate and a vital centre for

Thanks and appreciation for the efforts made to announce this reserve and to

biodiversity in terms of numbers and species diversity and distribution. Barr

prepare and publish this book. May Allah guide us towards preserving the

Al Hikman Peninsula occupies the largest part of the wetlands reserve area,

resources of this benevolent country.

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Foreword by Chris Breeze Country Chair, Shell Development Oman The Sultanate of Oman is a place like no other. From mountains peering out

the ecological richness of this particular reserve is paramount to the well-

of the sea to stretches of pristine desert, to lush, untouched wetlands, the

being of numerous species, as well as the many other marine and terrestrial

ecological diversity has created a unique environment within the country.

species that too depend upon it throughout the year.

Throughout Shell Development Oman’s long-standing presence in Oman,

Our work is not done with the printing of these pages, as there is still much

respecting the environment has always been an important aspect of our

more for us to learn to fully understand the complexity of this largely

sustainable development. We know that the choices we make matter and

undisturbed area and how it functions throughout the year. The value of this

the impact goes beyond ourselves. Through the invaluable collaborative

book should go beyond the interest of wildlife enthusiasts, as the importance

efforts between Ministry of Environment and Climate Affairs and Wetlands

of this reserve is just another way for us to realize that we are all connected.

International we have had the privilege to support the publication of this

Time and again we have witnessed what can be accomplished when

very important book.

governments, industry leaders and communities come together with a

The Wetlands Reserve is one of the most important components of the

common objective to conserve, preserve and protect what is precious and

African–Eurasian flyway for waterbirds. After years of study, we know that

essential to our global well-being.

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Wetlands International

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Foreword by Jane Madgwick CEO, Wetlands International In a region dominated by arid landscapes, Barr Al Hikman is a wetland pearl.

safeguarded. This is a message that Wetlands International wholeheartedly

An oasis for nature that is intricately connected to its history and dynamic

supports and seeks to act upon. We are committed to support conservation

natural processes. As well as the national and international significance of

efforts here, together with government and other partners. An international

the area for birds, turtles, whales and fish, this wetland is of paramount

recognition under the Ramsar Convention would be an important step in the

importance for people. Its function as a fish nursery is vital to the region.

right direction and it is encouraging the Ministry of Environment and Climate

This wetland is so special, and yet so little known, that we feel its story needs

Affairs has indicated the intention to go that route.

to be shared. In this book we aim to unveil its secrets. Words alone cannot do

We are honoured to collaborate with the remarkable group of people who have

it justice, so it is with pictures that we endeavour to capture the natural

taken the initiative to create this book. We thank our partners the Ministry of

beauty and reveal its remarkable stories of life.

Environment and Climate Affairs and Shell Development Oman for working

The book conveys the message that Barr Al Hikman must be cherished and

with us to allow this book to tell Barr Al Hikman’s story.

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‫جيم دي فو‬ ‫رويالند بوم‬ ‫وارد هاجميجير‬ ‫أندرو ثورب‬ ‫ريمون كالسين‬ ‫تصوير جان فان دي كام‬


Barr Al Hikman Shorebird paradise in Oman Jimmy de Fouw Roeland Bom Ward Hagemeijer Andrew Thorpe Raymond Klaassen

Photography Jan van de Kam


2-4-6 14 16

1

44

2

62

3

88

4

108

5

136

6

158

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CONTENTS

Forewords 3-5-7 Remote and beautiful

15

1 Desert meets ocean

17

2 Shorebirds on the move

45

3 Teeming with birds!

63

4 A rich and varied ecosystem

89

5 Eat, or be eaten

109

6 Ecologists at work

137

7 Safeguarding this paradise

159


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About the authors Jan van de Kam is a Dutch wildlife photographer with a (long) lifetime of experience of photographing, filming and writing about animals, plants, landscapes and conservation. Now he is focused primarily on coastal areas and shorebirds and is spending most of his time following these migrating birds all over the world. For the pictures in this book he visited Barr Al Hikman six times. Jimmy de Fouw is a biologist currently working at the Radboud University in the Netherlands. His research focus is on ecological functioning of wetlands. His objective of research is to transfer the mechanistic understanding of ecosystems into prescriptions for management. In 2007 he was one of the initiators of ecological research at Barr Al Hikman. Roeland Bom is a biologist from the Netherlands with a special interest in intertidal areas. He works at the NIOZ Royal Netherlands Institute for Sea Research. For his PhD, Roeland studied the interaction between Crab Plovers and crabs, and developed a strong fascination for both. He visited Barr Al Hikman more than ten times and has spent more than a year of his life in the area. Ward Hagemeijer is a biologist from the Netherlands. Having trained as an ornithologist and aquatic ecologist, he works for Wetlands International on the conservation of wetlands and their biodiversity, around the world. Ward organized and participated in a number of waterbird surveys at Barr Al Hikman and continues to work on the conservation of the site.

978 90 5882 015 0 :ISBN

First published in 2018 by Wetlands International, The Netherlands Concept and photography: Jan van de Kam. Authors: Jimmy de Fouw, Roeland Bom, Ward Hagemeijer, Andrew Thorpe and Raymond Klaassen.

Andrew Thorpe is a retired ecological consultant and has been an amateur ornithologist in the UK for over 40 years. He has a particular interest in survey work: he organized and participated in many of the earlier shorebird counts in Oman, and delivered a training course to a group of Omani environmentalists aimed at developing their skills as surveyors. Raymond Klaassen is a biologist from the University of Groningen. He is interested in animal movement, both at local scales (e.g. habitat use) and globally (e.g. migration). Expeditions to Siberia, to study the breeding ecology of Arctic shorebirds, fuelled inspiration for expeditions to Barr Al Hikman to study them also in their wintering range.

Text editor: John Marchant Arabian translation: The Typesetter. Proof check by Ibrahim Al Zakwani and Aziza Saud Al Adhubi Design and artwork: Teo van Gerwen – Design, The Netherlands © Copyright 2018 Wetlands International and Jan van de Kam. All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any informationretrieval system, without the prior written permission of the copyright holders. ISBN: 978 90 5882 015 0

Shell Development Oman

Acknowledgements The production of the book was generously supported by Shell Development Oman. The authors gratefully thank the Ministry of Environment and Climate Affairs (MECA) of Oman for their long-term collaboration and guidance and for the contributions. MECA’s team that contributed during the production must be acknowledged: Ali Naseer Hassan, Thuraya Said Al Sariri, Suleiman Naseer Al Akhzami, Ali Al Kiyumi, Hilal Sultan Al Shukaili, Aziza Saud Al Adhoobi, Taha Masoud Al Khodhoori, Moza Khalf Al Riyami and Abdullah Saleh Al Subhi. The book is based on a decade of work in Barr Al Hikman. It is not possible here to do justice to all those that contributed to this work by naming them. All those people who have joined us voluntarily in the field over the years, a big thank you goes to all of them. Many people from several other institutes have supported our work, through logistics, financially or in other ways. Therefore we kindly thank the Remote Sensing and GIS Centre and the Department of Biology of the Sultan Qaboos University (SQU), The Environmental Society Oman, Embassy of the Kingdom of the Netherlands in the Sultanate of Oman, the NIOZ Royal Netherlands Institute for Sea Research, Radboud University, University of Groningen, Wetlands International, The Research Council in Oman (TRC), the Oman Bird Records Committee, the Netherlands Organisation for Scientific Research (NWO), Natural Research Ltd, the Ornithological Society of the Middle East (OSME), Swedish Ornithological Society (SOF), Petroleum Development Oman (PDO) and the Working Group International Waterbird and Wetland Research (WIWO).

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Remote and beautiful The Sultanate of Oman is proud to be home to a pristine jewel – Barr Al

In particular, the large number of waterbirds present at the site, clearly

Hikman. The hugely rich birdlife of Barr Al Hikman is the most visible

qualifies it to be designated as a Ramsar site.

evidence of the wealth of its diverse and healthy ecosystem. Supporting

The beauty of Barr Al Hikman remained virtually undiscovered until the

more than half a million waterbirds, this is the single most important site for

1970s. Since then the area has become renowned for its rich mudflats, its

shorebirds on the flyway between western Asia and East Africa. The beauty

stunning landscapes, its coral reefs, its large numbers of birds, its turtles

of its landscapes, and its value for nature and for people, present Oman with

and for the dolphins and whales that occur in the waters offshore. For a

a heavy responsibility to conserve this unique place.

decade now, an international group of ornithologists and ecologists has

Its remoteness has helped preserve Barr Al Hikman in the past. Nowadays,

been gradually unravelling the secrets of this unique nature reserve. We

however, this relatively untouched area needs active protection, otherwise

as authors now welcome this opportunity to share our admiration for and

a critically important hotspot for biodiversity will be lost. International

knowledge of Barr Al Hikman with the broader public, both in Oman and

recognition will help to preserve Barr Al Hikman’s unique qualities.

abroad.

REMOTE AND BEAUTIFUL

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1

16


1

Desert meets ocean

17


‫أطراف الصحراء‬

‫‪18‬‬


The edge of the desert The coast of Oman is well known for its beautiful sandy beaches and rocky

abundance of marine life becomes evident. The mudflats are crowded with tens of

shoreline, but at Barr Al Hikman, a five-hour drive from Muscat, it is mudflats

thousands of birds feeding busily: this is shorebird paradise!

that dominate the coastline. Anyone who enters the Barr Al Hikman peninsula

The shallowly sloping coast is hugely transformed by the twice-daily advance and

from the west will have passed through endless sandy desert with scattered

retreat of the sea. As the tide drops, the mudflats are exposed to the air and their

low shrubs, a very familiar Omani landscape. Towards the coast, the sandy

abundant invertebrate animals, including various worms, crabs and molluscs,

desert changes into a sun-baked salt pan – the sabkha – a mixture of mud,

become available to feeding birds. At high tide the mudflats will be underwater

sand and seawater. Within the sabkha, fossils from the late Holocene era can

and fish invade the area for their own daily meals. There are people, too, on small

be found – traces from the coastlines of thousands of years ago – as well as

boats, trying to catch these fish. Thus Barr Al Hikman, in its present relatively

peculiar, needle-like, gypsum crystalline formations on the sabkha surface.

pristine state, is not only a pearl for biodiversity but also a valuable resource for

On arriving at its outer edge, where a shallow dune ridge with low evergreen

human society.

shrubs marks the transition between the sabkha and the sea, the astonishing

DESERT MEETS OCEAN

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‫إيران‬ IRAN

5

‫إالمارات العربية المتحدة‬ UAE

‫المملكة العربية السعودية‬ SAUDI ARABIA

‫عمان‬

A satellite image of Barr Al Hikman. The grey-green colours bordering the coast show the extent of the intertidal mudflats. Deeper waters show as a darker, blue-green colour. Copernicus Sentinel data 2018, processed by ESA.

OMAN

‫اليمن‬

YEMEN

‫محوت‬

Mahoot

17

6

‫فلم‬

7

Filim

‫محوت‬

Mahawt

8

‫غبة حشيش‬

Gubbat Hashish

‫الخلوف‬

Al Khaluf

‫خور الملح‬

N 10 km

)‫(البح�ات الجنوبية‬ ‫ي‬

‫ كم‬10

Khawr Al Milh

(southern lagoons)


‫النجدة‬

Al Najdah

35

‫خور‬ Landscapes of Barr Al Hikman

Khawr Barr Al Hikman

1

‫شنة‬

Shannah

‫المعاول‬

Ma'awil

2 1

‫ السهول الطينية المد والجزر مع‬2 ‫الميناء العبارة‬ 3 4 5 6

3

7 8

1 The ferry to Masirah 2 Intertidal mudflats with ferry harbor 3 Mangroves 4 Small bays with rock formations

‫مص�ة‬ ‫ي‬

5 Sand and gravel plains, with shrubs

MASIRAH

6 Coastal sand dunes, with shrubs

4

7 Bay fringed by sandstone hills 8 Evergreen southern lagoons

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22


Tidal transformations The gravitational pulls of the sun and the moon move the waters of the oceans around the globe. In combination with the topography of the ocean basin, including the coastline, they New moon

Full moon

determine the particular tidal regime experienced at each place. Here at Barr Al Hikman the distinctive result is two low and high tides each day that differ greatly in amplitude, a type of tidal cycle known as ‘mixed semidiurnal’.

Water level (m)

The tidal changes completely transform the landscape. Here at the east coast, near Shannah, the sea withdraws for many kilometres during spring tides. The state of the tide controls the activity of the different organisms using the mudflats: at high Time (days) The tidal cycle changes during the course of the day (white) and night (grey). The difference in height between low and high waters over about half a day varies in a two-week cycle. Spring tides occur approximately twice a month, during full and new moons, when the tidal range is at a peak.

tide, large numbers of fish and swimming crabs utilize the rich feeding grounds and, when the mudflats become land again, many feeding birds take over.


Salt

PHOTO © WARD HAGEMEIER

Continental sabkha

Evaporation Former coastline with ancient dunes Between land and sea A large part of the peninsula and the bay consists of

Salt

sabkha – a mixture of sand, salt and mud. Two types of sabkha are distinguished. The lower ‘coastal’ sabkha gets flooded with seawater during the highest tides, either through the creeks or from below ground. The higher ‘continental’ sabkha is supported by continental

Inland ground water Run-off

groundwater. During heavy rains, water runoff from the continental sabkha feeds the adjacent coastal sabkha. Salt deposits can accumulate, due to the rapid evaporation, or be set in motion again by rainwater. 24

Continental sabkha

Coastal sabkha


Coastal sabkha

High-tide roost

Tidal mudflats

PHOTO © MARCEL KERSTEN

Dunes

High-water level Low-water level Coastal dunes

Seawater

Intertidal mudflats DESERT MEETS OCEAN

Subtidal 25


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Above the tideline Further inland, the terrain is characterized by shifting sandy hillocks on gravel plains, with patches of evergreen shrubs and scattered acacia trees Acacia tortili, all adapted to drought. More than 25 species of reptiles live on the peninsula, such as this Carter's semaphore gecko Pristurus carteri. The beautiful Cream-coloured Courser, a shorebird adapted to harsh desert conditions, also lives here. The present geomorphology of Barr Al Hikman is the result of a drop in sea level 21,000 years ago. Ancient channels, lagoons and coastlines can be found a long way inland from where the sea is now: these are often demarcated by large numbers of shells, which betray that this land once belonged to the sea. Another spectacular phenomenon is the crystalline gypsum needle-like formations that can be found in the older sabkha. They form when soluble

PHOTO Š JIMMY DE FOUW

mineral sediments crystallize, as water is lost through evaporation.

DESERT MEETS OCEAN

27




28


Harvesting the salt Due to its frequent flooding with seawater and the rapid evaporation, the sediment is rich in crystalline salt. As in many other places worldwide, commercial salt pans where salt is raked into piles and harvested are a feature of the sabkha. The sabkha is an inhospitable place, but it is far from lifeless! Cyanobacteria grow in pools of shallow water and the resulting bacteria-rich crust cracks and forms polygons as it dries out in the heat

" . This process

attracts lots of small flies, which in turn are food for small shorebirds. In the vehicle tracks, which are first to flood, cyanobacteria are quick to regrow whenever the water returns.

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‫الصورة © ‪ /‬السيد أحمد التوقي ‪ ،‬مسقط‬

‫‪PHOTO © MR. AHMED ALTOQI, MUSCAT‬‬

‫‪30‬‬


The outer dunes One or more low, narrow strips of sand dune with sparse vegetation mark the transition from the land to the sea. The evergreen shrubs are halophytes – plants adapted to salty conditions – like species of Atriplex saltbushes and seepweeds of the genus Suaeda. The remarkable courtship display of the male Greater Hoopoe Lark can be admired here. He rises into the sky on fluttering strokes of his black-and-white wings then plunges down, with wings closed, while uttering a far-carrying, piping song with rising and falling pitch and tempo. Also remarkable is the yellow flower of the desert hyacinth Cistanche tubulosa emerging directly from the sand. It is a parasite that extracts its energy from the roots of other plants.

DESERT MEETS OCEAN

31


Intertidal mudflats This is shorebird paradise! The intertidal mudflats are one of the most important elements of Barr Al Hikman and are among the richest wildlife habitats in the world. The abundance of life is not directly visible, as most animals lie buried in the sediment or are hiding among the seagrass or in the mussel beds. What catches the eye is the extraordinary number of birds feeding and the wide variety of opportunities the intertidal zone offers to plants and animals of differing lifestyles. Patches of barren mud with gullies are interspersed with seagrass meadows, mussel beds and low rock formations with soft corals. At the east coast at low tide, one can walk out for four kilometres before reaching the sea’s edge, passing through all these magnificent habitats.

DESERT MEETS OCEAN

33


Sharing the peace and quiet Omani people from the nearby cities use the area for weekend relaxation. Small huts, constructed from palm leaves on the higher parts of the dunes, provide muchneeded shade. Visitors enjoy the peaceful environment by catching and cooking fish, brewing Omani coffee and eating Oman’s delicious dates. If kindly offered refreshment, no passing stranger should ever refuse to

PHOTO Š ROELAND BOM

share a bite!

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DESERT MEETS OCEAN

35


Catching fish and crabs The shallow waters off Barr Al Hikman teem with fish and crabs. They form a nursery ground for several quarry species of economic value and so underpin the fisheries sector of the Omani economy. The fishing grounds are fundamentally important, not only as a food resource for people but also as a key component of a healthy natural ecosystem.


Blue lagoons The blue waters of the lagoons, mixed with the greens of samphires and other small succulent halophytes, provide another, distinctly different scene. Large roosts of terns can gather here. The beautiful lagoons are shaped by water flow and by strong winds during periods of extreme weather.


40 PHOTO © MR ABDULLAH SALEH AL SUBHI (MECA)

)MECA( ‫ عبد هللا صالح الصبحي‬/ ‫الصورة © السيد‬


The tidal forest Along the coast grow patches of grey mangrove Avicennia marina, varying in extent from a few trees to the well-developed forests that are found on the east coast and on the islands of Ma’awil and Mahawt. Mangroves are closely adapted to a salty environment. Their leaves excrete salt that otherwise would build up inside the plant. There are unusual aerial roots that aid respiration, as oxygen is scarce in the mineral-rich sediment. When seeds drop from the tree they can germinate immediately on the mudflats nearby. Mangroves support a huge diversity of animal life, including abundant herons, kingfishers, songbirds, fiddler crabs and fish. Camels venture onto the mudflats to eat the leaves of the mangroves.

DESERT MEETS OCEAN

41


Marine meadows The largest bay is called Ghubbat Hashish, which means Bay of Grass – referring to the extensive seagrass meadows that grow in the shallow water. Dolphins and turtles are common in this bay and local fisherman harvest shrimps and lobsters. On the southeast coast of the peninsula, small bays with white beaches and corals provide another change of landscape. In the rocks surrounding the bays there are many relatively young marine fossils, showing that these rocks were once seabed.

42


DESERT MEETS OCEAN

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2

44


2

Shorebirds on the move

45


46


To, from and via Barr Al Hikman The half million birds that occur at Barr Al Hikman do not live here throughout the year. They are travellers from northern breeding areas – migratory birds, from the heavy Curlew to the featherweight Little Stint – that come to Oman to benefit from benign wintering conditions, such as favourable weather, plentiful food and relative safety. In spring, they return to their breeding sites to nest and to raise their chicks. At Barr Al Hikman, birds with very different breeding origins flock together in winter. Some species come all the way from the Arctic tundra at the northern edge of the continent. Others make shorter journeys, since they breed in temperate areas or the cold, semi-arid deserts of Central Asia. Others again move only quite short distances and spend their whole year within the Middle East. Some of the migrant shorebirds make astonishing journeys of many thousands of kilometres between breeding and wintering sites. They cannot complete these journeys in a single flight but must stop along the way to rest and refuel for the remainder of the journey. And before beginning a migratory journey they need to prepare for the long travels ahead – accumulating energy reserves to fuel the flight. There are also birds that spend the winter still further south, for example on the east coast of Africa, and visit Barr Al Hikman in autumn and spring to refuel. Barr Al Hikman therefore represents a key node in a worldwide network of breeding, wintering and stopover sites.

SHOREBIRDS ON THE MOVE

47


Annual cycles Many shorebird species breed in the high Arctic. Here they profit from the short summer surge of insects – ideal food for the fast-growing chicks – though conditions may be much harsher than they encounter during the Barr Al Hikman winter. Upon arriving in the breeding areas, they may find the tundra still covered by snow. These Curlew Sandpiper chicks are facing a 6,000-kilometre journey to reach Barr Al Hikman. But most Curlew Sandpipers use Barr Al Hikman as a stopover site, replenishing their energy stores before continuing their migration for another 6,000 kilometres towards South Africa!

48


Annual cycle of a migratory bird

‫تز‬ ‫ال�اوج‬ ‫قضاء الشتاء‬ ‫الهجرة‬

breeding wintering migration

M SUM ER

‫ا لصيف‬

‫شتاء‬

WINTER

‫الطيطوى النهقية‬ ‫تز‬ ‫ال�اوج‬ ‫قضاء الشتاء‬

‫الهجرة‬

Curlew Sandpiper breeding breeding wintering wintering migrationmigration breeding wintering migration

Curlew Sandpiper

SHOREBIRDS ON THE MOVE

49


'

Shorebird flyways A flyway is the entire range of a migratory bird species through which it moves on an annual basis, from the breeding grounds to non-breeding areas (including intermediate feeding and resting places). Worldwide, about eight shorebird flyways can usefully be distinguished, though with broad overlaps and some remaining uncertainties: these are the birds’ highways. Barr Al Hikman is a key site within the West Asian – East African flyway (outlined in red) and birds that winter in eastern and southern Africa pass Barr Al Hikman during autumn and spring migration. Most birds at the site are using this flyway, but recent research has shown that Little Ringed Plover, Broad-billed Sandpipers and Red-necked Phalaropes from Scandinavia winter in Oman, suggesting a new ‘Scandinavian – Middle Eastern’ flyway (in yellow). Remarkably, the Red-necked Phalaropes ! do not winter at Barr Al Hikman itself but on open water in the Arabian Sea!

50


1 2

87

3

4

11 5 6

9

10

12

Gatherings of hundreds of thousands of shorebirds can be enjoyed at only a very few locations around the world. The dots on the map show where these most important intertidal wetlands lie. Flyways form a web that connects these key sites at a global scale. 1 Copper River delta, Alaska 2 James Bay, Canada 3 Bay of Fundy, Canada 4 Mudflats of Guyana and neighbouring countries 5 Banc d’Arguin, Mauritania 6 Arquipélago dos Bijagós, Guinea-Bissau 7 Wadden Sea, North-west Europe 8 Estuaries of Great Britain 9 Gulf coast, Middle-east 10 Ganges/Brahmaputra Delta, Bangladesh and India 11 Yellow Sea, China and Korea 12 Roebuck Bay, Australia • Barr Al Hikman

SHOREBIRDS ON THE MOVE

51


‫الطيطوى الشدقاء‬ ‫تز‬ ‫ال�اوج‬ ‫قضاء الشتاء‬

‫الهجرة‬

Broad-billed Sandpiper breeding breeding wintering wintering migrationmigration

breed

winte

migra


East meets west Shorebirds from very different breeding origins, from Europe to eastern Siberia, mix together at Barr Al Hikman during winter. Though the breeding grounds of the Broad-billed Sandpiper extend all across Eurasia, ringing has shown that the Broad-billed Sandpipers wintering in Oman have come from Scandinavia. By contrast, Great Knots nest only in eastern Siberia. Most birds of this species winter in Australia and only a very small number in the Middle East. No one knows whether they arrive at Barr Al Hikman along the coast or take an overland route across Central Asia.

‫الطيطوى‬ ‫الكب�ة‬ ‫ي‬

‫تز‬ ‫ال�اوج‬ ‫قضاء الشتاء‬

‫الهجرة‬

Great Knot breeding breeding wintering wintering migration migration

breeding wintering migration

Great Knot

SHOREBIRDS ON THE MOVE


�‫الكب‬ ‫قطقاط الرمل ي‬ ‫تز‬ ‫ال�اوج‬ ‫قضاء الشتاء‬

‫الهجرة‬

Greater Sand Plover breeding breeding wintering wintering migrationmigration

breedin

winterin

migratio

Greater sa

54


Long, medium and ‘short’ migrations Most of the shorebirds wintering at Barr Al Hikman travel thousands of kilometres per year. For example, Curlew Sandpipers cover as much as 12,000 kilometres on their annual migrations. But not all shorebirds are long-distance migrants. Familiar at Barr Al Hikman are the Greater and Lesser Sand Plovers that breed in semideserts throughout Central Asia. Depending on their breeding origin, members of these species can be considered as short-distance or medium-distance migrants: birds travel about 3,000 kilometres each way to winter at Barr Al Hikman but others visiting Australia must fly up to 8,000 kilometres.

�‫الصغ‬ ‫قطقاط الرمل‬ ‫ي‬ ‫تز‬ ‫ال�اوج‬

Lesser Sand Plover

‫قضاء الشتاء‬

wintering wintering

‫الهجرة‬

breeding breeding

migrationmigration breeding wintering migration

Lesser sandplover

SHOREBIRDS ON THE MOVE


Crab Crab plover plover

‫الحنكور‬ ‫ت‬

‫ز‬ ‫ال�اوج و قضاء‬ Crab‫الشتاء‬ plover ‫قضاء الشتاء‬

Crab Plover

Crab Plovers: our regional celebrity

Resident (breeding) breeding and wintering Resident (breeding)

The Crab Plover is one of the most charismatic and

wintering wintering wintering

easily recognisable of the world’s shorebirds. Most unusually among migrant birds, the young ones travel to Resident (breeding) the wintering grounds alongside their parents and still depend partlywintering on them for food after arrival. A striking

peculiarity is that, unlike other shorebirds, they do not nest on open ground but colonially in burrows on sandy offshore islands. Crab Plover colonies are found only in the region surrounding the Arabian Peninsula, including on nearby Masirah, and so the Crab Plover is another example of a short-distance migrant.

56


Amazing journeys Migratory travels are physically very demanding! Birds need to prepare for long flights by storing energy reserves in the form of body fat, and some almost double their body mass before migration. At the extreme, well-fed shorebirds can fly for seven days and cover up to 10,000 kilometres without stopping! Most birds cannot make their journey in one go, however, but need to stop a few times along the way to refuel. In order to complete their travels, therefore, migrants depend on there being a set of sites along their route where healthy ecosystems can be relied upon to provide them with the food they need. Loss of any one of these sites could cause a whole flyway to collapse!

SHOREBIRDS ON THE MOVE


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Migration mysteries For many of the waterbird species that winter at Barr Al Hikman, little is known about where they come from and how they get here. For example, the breeding grounds of the flamingos and terns that occur in Barr Al Hikman in winter still remain a mystery. We need to understand the migration routes and breeding areas of these populations far more fully, in order to arrive at year-round strategies to conserve them.

SHOREBIRDS ON THE MOVE

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3

Teeming with birds!

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But how many? A spectacular half a million waterbirds rely on Barr Al Hikman in winter, and their diversity is also extraordinary! Many different species of shorebirds occur, from the small grey-brown sandpipers and sand plovers to the larger Bar-tailed Godwit and Curlew – and the conspicuous, black-and-white Oystercatchers and Crab Plovers. In addition, we find large flocks of gulls near fishing harbours and many species of terns feeding over the sea. Then there are the larger birds like herons and egrets, the occasional Spoonbill, and the pink Greater Flamingos that tower high over all the other birds. The counting of bird numbers is crucial to establishing the importance of Barr Al Hikman on the global scale. By convention, a site is considered internationally important for a shorebird if it regularly hosts more than 1% of the population size of that species estimated

for the whole flyway. Recent surveys have revealed that Barr Al Hikman meets this criterion for no fewer than 18 species. Repeating the counts in subsequent years allows researchers to monitor whether individual species and the site in general are doing well, or whether problems are arising. As birds are at the top of the food web, their numbers help to indicate whether the whole ecosystem is staying healthy. Monitoring birds at Barr Al Hikman is no easy task in this vast and remote place. Visibility is often hampered by heat haze, and birds of prey might frustrate the counters by scaring the roosting birds. It can be hard even to find the roosting flocks in the extensive sabkha. Surveyors have often got their vehicles stuck while searching these vast areas of sand and water‌


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High-tide gatherings The incoming tide forces the shorebirds to stop feeding on the mudflats and at high tide they gather into huge flocks to rest. Large flocks can be found roosting on the shoreline and on the sabkha. High tide is the best time to survey the birds as they are then aggregated into a limited number of roosts. Individuals tend to gather with members of their own species, although mixedspecies flocks also occur: Great Knots typically roost with Bar-tailed Godwits, and sandpipers mix frequently with sand plovers.

TEEMING WITH BIRDS!

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Where to roost Shorebirds roost on the ground, often along the shoreline or on a spit or sandbank out of reach of the rising tide. Egrets often seek a safe and dry place to perch high in the mangroves. Cormorants, sometimes in thousands, can be seen commuting between the sea and their roost in the Khawr Barr Al Hikman lagoon.


Roosts on the sabkha Most shorebirds roost at the shoreline. The full importance of inland roosts on the sabkha, especially during very high tides, has only been realized quite recently. It is difficult to survey the birds roosting on the sabkha, however, as the flocks are widely scattered and the sabkha is never easy to access by car.


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Roosting behaviour The main objective for birds at the high-tide roost is to rest and recuperate. In addition, they often take the opportunity to bathe and to preen their plumage. It is important that people avoid unnecessary disturbance to birds at their roosts, because they need this time to prepare for their next feeding session during low tide.

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Making the counts So as not to disturb the roosting birds, the flocks are surveyed from a safe distance using telescopes. Heat haze that distorts distant viewing, and birds of prey scaring the birds away, can make counting birds at their roosts very frustrating! Another typical problem for the surveyors at Barr Al Hikman is getting stuck in the sabkha‌ and having to dig out your vehicle is a common experience as one never knows whether the ground can take its weight. Even when the sabkha looks dry, there can be soft wet

PHOTO Š LENZE HOFSTEE

mud hidden just below the surface.

TEEMING WITH BIRDS!

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max count

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500.000

20.000

15.000

10.000


Species

Crab Plover Eurasian Oystercatcher Kentish Plover Lesser Sand Plover Greater Sand Plover Grey Plover Ruddy Turnstone Sanderling Great Knot Curlew Sandpiper Dunlin Little Stint Broad-billed Sandpiper Eurasian Curlew Bar-tailed Godwit Common Redshank Common Greenshank Terek Sandpiper TEEMING WITH BIRDS!

�‫العر‬ ‫االسم‬ ‫مسالا‬ ‫ يبرعلا ب ي‬ ‫حنكور‬ ‫ روكنح‬

‫اس‬ ‫ راح‬ ‫محاري أور ي‬ ‫ يرزاق إسكندري‬ ‫زق‬ �‫صغ‬ ‫زقز‬ ‫ ريغاق ي‬ ‫زق‬ �‫كب‬ ‫ ريزاق ي‬ ‫ يدااق أرمد‬ ‫زقز‬ ‫قن�ة ماء‬ ‫ ءام‬ ‫ب‬ ‫طيطوى بيضاء‬ ‫ نا‬ ‫كب�ة‬ ‫ راق‬ ‫طيطوى ي‬ ‫طيطوى نهقية‬ ‫ ةي‬ ‫طيطوى دراجة‬ ‫ ةج‬ ‫صغ�ة‬ ‫ ةر‬ ‫طيطوى ي‬ ‫طيطوى شدقاء‬ ‫ ءاق‬ ‫نهقة أوراسية‬ ‫ ري‬ ‫قوق موشم ذنب‬ ‫ لي‬ ‫حمراء ساق‬ ‫ قا‬ ‫ض‬ ‫خ�اء ساق‬ ‫ قاس‬ ‫طيطوى رملية‬ ‫ ةي‬

Scientific name

Dromas ardeola

Globally significant results

The surveys reveal that the numbers of birds wintering at Barr Al Hikman are 8.759 impressive. About two-thirds of all birds were found along the east coast of the

Max. count

Haematopus ostralegus 5.434 peninsula, and the rest within Ghubbat Hashish and the southern lagoons. The counts confirm that Barr Al Hikman is of international importance for migratory Charadrius alexandrinus 1.879 waterbirds. Indeed, the number of species for which Barr Al Hikman hosts an Charadrius mongolus 123.369 important part of its total flyway population is unmatched, even from a global Charadrius leschenaultii 14.789 perspective. Pluvialis squatarola 4.106 Mapping the numbers, along with those at other nearby coastal areas, shows

Arenaria interpres

6.940 that Barr Al Hikman hosts far more wintering shorebirds than any other site

Calidris tenuirostris

in the Gulf region. With human pressures mounting on intertidal areas in the 3.638 region, the relative importance of Barr Al Hikman for shorebirds is increasing. ~1.000

Calidris ferruginea

36.911

Calidris alba

Calidris alpina

129.046

Calidris minuta

17.940

Calidris falcinellus

~5.000

Numenius arquata

14.518

Limosa lapponica

87.180

Tringa totanus

36.845

Tringa nebularia

1.501 Maximum counts at Barr Al Hikman for the wintering

shorebird species for which 1% of the estimated Xenus cinereus 1.726 flyway population is exceeded.

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Key species: sandpipers and sand plovers These small birds account for more than half of all the shorebirds wintering at Barr Al Hikman. It may be hard to distinguish the different species when they are mixed together and in their greyish winter plumages. At close range, however, they are all surprisingly distinctive, and the species become easier to separate.

TEEMING WITH BIRDS!

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Key species: Bar-tailed Godwit Barr Al Hikman is the most important wintering site for this large shorebird on the West Asian – East African Flyway. In contrast to the short-legged sandpipers and sand plovers, that are restricted to the mudflats and drier ground, the long-legged Bar-tailed Godwits can also wade and rest comfortably in shallow water.

TEEMING WITH BIRDS!

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Key species: Crab Plover The iconic Crab Plover is one of the most extraordinary shorebirds of Barr Al Hikman. It is certainly the species any birdwatcher visiting the area will most want to see. Crab Plovers breed only in the Middle East, and Barr Al Hikman, with several thousand wintering birds, forms one of its main wintering sites.

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Key species: Oystercatcher The Oystercatcher, with its bright red bill, pink legs and black-and-white plumage, is a very striking bird. Although the number of Oystercatchers at Barr Al Hikman can account for up to 20% of the flyway population, specialist mollusc-feeders like the Oystercatcher are relatively rare at Barr Al Hikman. This is because the various types of molluscs that are present here are mostly either buried too deep in the sediment to be accessible or have protected themselves with unusually thick shells.

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Key species: gulls and terns Huge gull and tern flocks are not unusual at Barr Al Hikman, although the numbers can vary considerably between years. Gulls occur mainly near villages, where they can capitalize on the catches brought in by fishermen. All 16 species of tern that occur in the Middle East can be found at Barr Al Hikman, though some of these have a predominantly pelagic lifestyle and return to land only to rest.

TEEMING WITH BIRDS!

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A rich and varied ecosystem

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The intertidal food web Tropical coastal ecosystems, such as at Barr Al Hikman, are among the world’s most productive and biodiverse. ‘Primary producers’, including seagrasses and algae, support all the other elements of the system. They grow by the process of photosynthesis, a series of chemical reactions that uses light, carbon dioxide, water and other simple nutrients to create the larger molecules that all living things need. At Barr Al Hikman, these ingredients are all abundant and conditions for photosynthesis are ideal. Seagrasses and algae are the main food for a great variety of small animals that live on or within the seafloor (the ‘primary consumers’). These are in turn eaten by shorebirds, fish and larger crabs (the ‘secondary consumers’). Filter feeding, decay and other strategies tangle this simple sequence into a complex ‘food web’, with many interconnections between species. The richness of life at Barr Al Hikman becomes visible at low tide. Sea snails glide over the surface and small crabs emerge from their burrows. In shallow pools, anemones wave their tentacles, and sponges and sea squirts pump water through their bodies. In addition, a hidden world of animals exists within the mud itself, revealing its presence only by burrows in the sediment and casts left on the surface. The small animals, including sea snails, clams, worms and small crabs, are food for shorebirds, fish and larger crabs. But they also change the nature of the landscape by constructing reefs or mussel beds or by helping to redistribute the sediment, thus creating new opportunities for other, more specialized species. Much of what happens at Barr Al Hikman is about eating and avoiding being eaten. To defend themselves against being eaten, many of the small animals bury deep into the sediment, or build strong shells. In response, the shorebirds have evolved long bills with which they can locate deeply buried prey, and crabs have developed powerful claws that can crack thick shells.

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Capturing energy from the sun As soon as sunlight reaches the surface of the exposed mudflat, tiny single-celled organisms called diatoms start to grow. Through photosynthesis, they capture and store the energy of the sun. We cannot see diatoms as they are much too small, but the greenish-brown sheen that develops on the mudflats during low tide is evidence of their abundance. Diatoms are at the base of the food web and are the staple diet for many other organisms, such as these Cerithium scabridum sea snails which occur at Barr Al Hikman in extremely high densities.

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Life in the seagrass beds Seagrasses are, like diatoms, primary producers that use sunlight to grow. Many animals depend on them for food. Two seagrass species are common in the intertidal area, Halodule uninervis and Halophila ovalis. A third species Thalassia hemprichii grows permanently underwater, just below the low-tide mark, and is an important food for turtles. Seagrass beds also provide shelter for many organisms from the sun and from the power of the waves, and trap sediments and nutrients – the jewel-like, zoned paper bubble snail Hydatina zonata can be found here.

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PHOTO © JIMMY DE FOUW

A RICH AND VARIED ECOSYSTEM

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Hiding from predators Many of the smaller animals are buried most of the time, such as this venus clam. Keeping out of sight helps them to counter the constant danger of predators – birds during low tide and fish and swimming crabs at high tide. Only some very well-defended animals expose themselves at the surface, such as ghost crabs and some large spiny sea snails.

A RICH AND VARIED ECOSYSTEM

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Adapted to tidal life Conditions are very variable during low tide, as temperatures and salinity can rise or fall sharply and desiccation can occur due to evaporation. To live in the intertidal zone, animals must be fine-tuned to the tidal rhythm and well able to cope with the changes it brings. Those that are found close to its landward edge experience long periods of exposure to the air at low tide. Far out on the mudflats, however, the mudflats are exposed only at neap tides and never for very long. Here we find organisms such as sponges, anemones, tube worms and starfish that are adapted more closely to life under the water. 98


! "

Ecosystem engineers Several of the organisms that are found at Barr Al Hikman alter the area in such way that they create new habitats, not only for themselves but also for other species. These are the ‘ecosystem engineers’ – for example corals, that grow reefs, and seagrass, that creates meadows. Colonial serpulid tube worms are also ecosystem engineers, building massive tangles of interwoven calcareous tubes among which other animals, such as the red-eyed reef crab Eriphia sebana,

! . Another example is the common razor clam Pinna bicolor: " their large shells add structure can shelter

and stability to the mudflats, attracting more fish species and crabs.


Crabs that sift the sediment Up to fifty different species of crabs can be found at Barr Al Hikman. Small burrowing crabs live close to the shoreline, at densities of up to 300 crabs per square

." "

102

"

ILLUSTRATION Š MAAIKE EBBINGE

metre. In combination, these crabs turn over a huge volume of sediment in the process of extracting food particles. The tiny sand balls on the surface are the result of their work. Several species of burrowing crabs are social animals and some construct complex burrows in which entire families can be found

!.

The males display their big claws to attract females and to intimidate other males

".


A RICH AND VARIED ECOSYSTEM

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Predatory crabs Higher in the food web we find some larger crabs, which are among the most powerful predators at Barr Al Hikman. Blue swimming crabs Portunus segnis have extremely muscular claws

!

even very hard-shelled sea snails

'

! with which they are able to crush

' . The snails at Barr Al Hikman develop

extra-strong shells, to protect themselves better against the high risk of predation by crabs.

$

A RICH AND VARIED ECOSYSTEM

The red-eyed reef crab

$ is another fierce carnivore, here with a small

burrowing crab in its claw.

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!

" (

Ghost crabs The pyramid-like mounds of the ghost crab Ocypode spp. can be found all along the coastline

! . They are built

by males to attract females. Ghost crabs have big claws and large legs that make them strong and fast runners. They have little to fear from the smaller shorebirds, such

& , but sometimes a larger predator like a Crab Plover will manage to snatch one " .

as Turnstones

A RICH AND VARIED ECOSYSTEM


5

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5

Eat, or be eaten

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Finding food Food is plentiful for the birds at Barr Al Hikman, although most of it is buried in the sediment and not directly visible. But the birds are well equipped with the right tools and skills to find their hidden prey. Many shorebird species have long bills that they use to probe into the sediment to reach deeply buried worms and shellfish. Smaller sandpipers also have sensitive bill tips and, by ‘sewing’ through the mud surface, they can detect their prey by touch. Plovers have short, stout bills that not suited to probing. Instead, they adopt a wait-and-sprint strategy, catching worms and crabs by surprise when they emerge from their burrows. The mudflats are also full of microorganisms, which are taken for food by the largest birds in the area, the Greater Flamingos. They filter many litres of muddy water through unique, specialized structures in their bills to sieve out enough food for the day.

EAT, OR BE EATEN

In addition, the creeks and shallow waters are full of fish. Long-legged egrets wade through the water to grab fish with their long, sharply pointed bills. Terns fly low above the water and often capture fish with a spectacular plunging dive. Crabs are notably abundant at Barr Al Hikman and are preyed upon by many birds, including some species that feed more typically on worms, sea snails or clams elsewhere. Table manners differ between species: some take only the smaller crabs and swallow them whole, others dismantle larger crabs leg by leg, and others again can crack their bodies open with the power of their bill. The feeding birds need always to be alert to danger that might suddenly appear from the sky. Falcons and harriers prey on birds and hence form a constant threat. For shorebirds too, as much as for crabs and fish, finding food at Barr Al Hikman is a balance between eating and being eaten!

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The right tools Different types of prey animals all have their own way of escaping their predators. They can swim or run away, or bury themselves. They might be armoured with a thick shell or be able to fight back with sharp claws. Shorebirds, despite having only their bills to help them, are surprisingly well equipped to catch and handle their prey. The shape of the bill reveals what type of predator they are. Long bills are perfect for detecting and pulling up deeply buried prey, while short and stout bills are for shallow probing or pecking at the surface. Strong and sharp bills are used to dismember crabs to make them easier to swallow.

EAT, OR BE EATEN

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Iconic crab-eaters Crab Plovers mainly eat‌ crabs! Their big eyes and powerful bill are well suited for hunting them down. Whenever crabs emerge from their burrows to feed or to display, there may be a Crab Plover waiting silently to strike. Small crabs are swallowed whole. They also catch larger crabs swimming in the shallow waters but these cannot be swallowed until their dangerous claws have been detached.

EAT, OR BE EATEN

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Quick and resourceful A feeding Terek Sandpiper continuously scans the nearby mud for surfacing crabs. When one is located, the sandpiper sprints to the crab’s burrow to make a surprise attack. Even if the crab manages to retreat inside, the long curved bill of the sandpiper can often still reach it. Here, a Terek Sandpiper has captured a small Scopimera sand bubbler crab. EAT, OR BE EATEN

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A flexible diet Bar-tailed Godwits feed typically on marine worms at most mudflat sites they visit, but at Barr Al Hikman these worms occur at only rather low densities. Instead, the godwits show their versatility by feeding also on crabs, as do so many of the other shorebird species wintering at Barr Al Hikman.

EAT, OR BE EATEN

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$

!

Mollusc specialists Great Knots ! and Oystercatchers $ specialize in feeding on shelled molluscs, finding their prey by probing into the mud. Great Knots choose small items that they swallow whole and then can crush in their strong stomachs. Larger molluscs can be dealt with only by the Oystercatcher. By hammering and cutting with their strong bills, they are able to open their shells to eat out the flesh. Here at Barr Al Hikman, however, large molluscs are scarce and Oystercatchers take mostly the smaller ones instead.

EAT, OR BE EATEN

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56 - ON THE SEARCH FOR FOOD


Probing and pecking Sandpipers have highly sensitive bills that give them several options for finding food. At times they will carefully peck minute items from the surface, but often they probe rapidly into the mud like a small sewing machine, with feeding flocks leaving behind rows of little stitch marks. Because sandpipers feed by touch they are able to find food even during moonless nights. Some species eat the algal film that grows on moist sediments.

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Wait and sprint Plovers have relatively short bills and long legs and feed quite differently from the sandpipers. Between short runs, they scan the nearby mud with their big eyes, looking for subtle movements of water or sediment caused by the prey. When an unwary worm or small crab breaks the surface, the plover sprints over and seizes it. A captured worm must be pulled out patiently so as not to break it. Plovers spread out during foraging to avoid disturbing each other’s prey or competing for the same items.

EAT, OR BE EATEN

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Filter feeding Flocks of feeding flamingos typically first appear in the far distance as a shimmering pinkish haze. Surprisingly, these largest waterbirds at Barr Al Hikman feed on very small items of food! A feeding bird pumps muddy water through its upside-down bill, using its powerful tongue, and collects food items onto specialized filter plates inside. Flamingos trample their feet in shallow water to stir up microorganisms and tiny invertebrate animals, leaving behind a characteristic pattern of small round pools.

EAT, OR BE EATEN

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Fishing by eye Herons and egrets wade deeply, using their long legs, but may be motionless for long periods. When they see an unwary fish coming within reach, they shoot out their long bill and can catch it within the blink of an eye. A flick of the long, muscular neck often propels the whole head of the bird into the water. The Western Reef Heron occurs in two distinct morphs – white and grey. It is hard to believe that these very different birds belong to the same species!

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Fishing by touch The broad ends of a Spoonbill’s blunt bill are extremely sensitive to touch. A heron, like a Great Egret (facing page), will use its eyes alone to detect food but the similar-looking Spoonbills (this page) have a far more active way of fishing. They open their spoon-shaped bills and sweep them broadly from side to side while wading quickly through the water. Any fish or shrimps whose movements they can detect are quickly seized and swallowed.

EAT, OR BE EATEN

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Fishing frenzies! Sometimes a shoal of small fish that has entered shallow water becomes surrounded by herons and egrets working together, often with Slender-billed Gulls, to pursue them towards the shore. When the fish are trapped and have no way out, the result is a feeding frenzy! Fish try to escape in all directions, including by leaping into the air, but are relatively easy to catch. The commotion quickly attracts more birds, including terns, that also try to take advantage of the disorientated fish, until the last ones are captured or manage to slip away.


!


Danger from the sky When a flock of shorebirds rises high into the sky, one can be sure their sharp eyes have spotted a falcon, or another aerial predator, on the hunt for food. Just the threat of possible attack by falcons and other raptors exerts huge influence on where, when and how the shorebirds roost and feed. The commonest raptor at Barr Al Hikman is the Marsh Harrier

! , which can often try to snatch an

inattentive shorebird. Even the larger shorebird species, like the Crab Plovers, must constantly keep an eye on the sky for possible danger.


6

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6

Ecologists at work

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So much to discover! Just being at Barr Al Hikman and experiencing its abundance of birdlife raises many simple questions. Where do all the birds come from? How can Barr Al Hikman support so many wintering shorebirds? Ecological research is now beginning to provide answers to some of these questions – and insights that are interesting from a fundamental scientific point of view but also for conservation. Fitting a small metal ring to the leg of a bird, carrying a unique code, means that it can be traced back to its place of ringing if it is ever found again. Colour-coded rings that can be read from a distance can gather information on movement more efficiently. A more sophisticated method to study bird migration, now becoming available to researchers, is to fit birds with small tracking devices. Satellite tags and GPS loggers can provide an incredibly detailed picture of bird movements. To find out how shorebirds can winter at Barr Al Hikman in such large numbers, we need to discover what they eat and then measure how much of this food is available. We know there is a complex food web in the site’s ecosystem, in which the birds play a key role. Birds respond quickly when conditions become less favourable, for example by moving away to seek alternative sites. In this way, birds are indicators of a healthy ecosystem and, on a wider scale, can even be considered as sentinels of our changing world. For long-term conservation, we must try to understand how the whole ecosystem works. Much of the research conducted at Barr Al Hikman is therefore about how species interact with each other – for example through influencing behaviour or creating habitat, as well through the food web. Also relevant to ecosystem research are the physical aspects of the site and its connections with its surroundings, including the deeper waters far offshore. Barr Al Hikman is now one of the few areas within the Middle East where an extensive and advanced ecological research programme is conducted. This has provided the wealth of information presented in this book. But there is still much more that will be discovered, as research into birds and the ecosystem moves forward.

139


Shorebird ringing After dark, and when the tide is right, trained ringers can capture birds safely using very fine nets to catch them in flight. They extract each bird gently from the net and fit a metal ring that bears a unique number to its leg. After ringing, the bird is quickly released to resume its normal activities. If the bird is later found or recaptured at another location, the ring number links that location to Barr Al Hikman, and in this way connections between Oman and the rest of the world are gradually being established.

140


ECOLOGISTS AT WORK

141


Gathering biometrics During ringing, measurements are taken of each bird, including the lengths of the bill and wing. These can be used to infer its breeding origin, as birds from different breeding grounds may differ in size. In addition, its body mass and the state of its feathers are noted. These are measures of the general condition of the bird and of

"

how ready it might be to migrate. This is also visible on the mudflats: the heavy body and the wing-feathers in perfect condition show that this female Bar-tailed Godwit Barr Al Hikman.

142

" is ready to leave


Adding colour to the data Birds of some species have been fitted with coloured rings, in addition to their metal ring. Combinations of colour rings can be unique to individual birds. Observers can easily read a bird’s colour code from a distance, using a telescope, and this greatly increases the chance that a bird will be found again, at Barr Al Hikman or elsewhere. Observations of colour-ringed birds help not only to establish the connections between Oman and the rest of the world but also to gather important information on the survival rates of birds that helps monitor the health of their populations.

The map shows connections between Barr Al Hikman and other locations that have been discovered by using metal and colour rings. Broad-billed Sandpipers at Barr Al Hikman originate from Scandinavia and Dunlins from the Taimyr Peninsula in central Siberia. Several Great Knots ringed while migrating along the coasts of north-east Asia have been resighted at Barr Al Hikman. Crab Plovers ringed at Barr Al Hikman have been seen at their breeding grounds in Kuwait and along the Indian coast. A Bar-tailed Godwit ringed at Barr Al Hikman was shot close to its breeding grounds in northern Siberia – and one was also caught in the nets that had been ringed in South Africa.

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Tracking godwits to Siberia Migration patterns and breeding areas of Bartailed Godwits have been studied by fitting satellite transmitters to a sample of birds. The travels of these individuals towards their Siberian breeding sites could then be followed in great detail. The Aral and Caspian Seas turned out to be important refuelling sites along the flyway. After the breeding season, the tagged birds returned to Barr Al Hikman. In this flock two Bar-tailed Godwits with antennae can clearly be seen.

ECOLOGISTS AT WORK

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Tracking Crab Plovers as they forage To help us study in detail where and how Crab Plovers capture their crabs, we fitted some individuals with state-of-the-art GPS loggers. These tracking devices provide an extremely detailed picture of local movements and behaviour. This research showed that Crab Plovers rely heavily for food on swimming crabs, which they capture in shallow water. Dots on the map represent the activity of an individual bird for about 15 minutes. The bird leaves its roost and starts foraging when the tide starts falling.

‫جثم‬

Roost

‫تراوح مكانها‬ �‫س‬ ‫ي‬ �‫يط‬ ‫ي‬ ‫أقلق‬ ‫تأكل‬

Stand still

Walk

Fly

Peck

Eat

© 2018 Google

ECOLOGISTS AT WORK

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What do shorebirds eat? To understand why Barr Al Hikman attracts so many shorebirds, we need to know exactly what they eat. We can find this out by making careful observations of birds as they forage, but also by analysing their droppings! Larger food items, like those usually eaten by Curlews, can often be identified by eye but a microscope might be needed to see what the smaller birds are eating. Little Stints and Curlew Sandpipers sometimes appear to be eating mud, but what they are actually feeding on is a biofilm of microbes (diatoms and bacteria). ECOLOGISTS AT WORK

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The richness of life underfoot It is astonishing how much invertebrate life, like worms and molluscs, there is hidden in the sediment. To learn about the abundance of food for shorebirds, and on the functioning of the ecosystem as a whole, we need to know exactly what is down there. Standard core samples of mud are collected, washed and sieved, in order to estimate the densities of prey items in different parts of the site. Back in the field laboratory, each sample of sieved animals is sorted by species and prey items are measured and counted.

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Links to the ocean Barr Al Hikman’s ecosystem has broader links, not only to the distant places visited by its birds but also to the ecosystems around it, for example the ocean. Fish and swimming crabs move into the area twice daily to feed as the tide rises but Barr Al Hikman also functions as a nursery area for these and other marine animals. Juvenile animals move into deeper

PHOTO Š JIMMY DE FOUW

waters as they mature and then return to the shallow waters to spawn.

ECOLOGISTS AT WORK

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Micro-organisms to ecosystems At Barr Al Hikman there are many instances where species interact and depend on each other to survive. There are the cases we can observe – like the birds and their prey – though it is not all about food. We can also see, for example, how the seagrass meadows and reefs shelter juvenile fish and act as nursery grounds. But there are many less visible interactions that might nevertheless be of fundamental importance to the functioning of the ecosystem, and more detailed study is needed to find these. More has been learnt recently about sulphides, for example, which are chemicals that tend to build up in seagrass beds and can be toxic to animals and seagrasses

!

themselves if levels get too high. We now know that the tiny bivalve mollusc Pillucina vietnamica

! hosts sulphide-consuming bacteria in its gills. Thus

this small shell and its bacteria interact with seagrasses by detoxifying their environment, in a process of great importance for the whole ecosystem. We are, however, only just beginning to comprehend the complexity of Barr Al Hikman’s ecosystem.

ECOLOGISTS AT WORK

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7

Safeguarding this paradise

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)MECA( ‫ عبد هللا صالح الصبحي‬/ ‫حقوق النشر للصورة © محفوظة للسيد‬ PHOTO © MR ABDULLAH SALEH AL SUBHI (MECA)

SAFEGUARDING THIS PARADISE

Significant regionally and globally With its half million shorebirds, Barr Al Hikman is one of the most important coastal wetlands worldwide. It is a major component of migratory flyways, and so of critical importance for migrating birds at a global scale. The challenge of conserving migratory birds is to protect all the spaces they need to breed, to migrate and to survive the winter. This can be achieved only by countries working together, each playing their own role in safeguarding a part of the bird’s annual cycle. This basic philosophy, of considering migratory waterbirds as shared assets, lies behind international collaboration in treaties for nature conservation, such as the Ramsar Convention on Wetlands. All along the coasts of the Arabian Peninsula, many important intertidal areas have been degraded by human impact. Over time, therefore, the relative importance of Barr Al Hikman has increased at both regional and global scales. Its remote location has helped to safeguard the pristine condition of Barr Al Hikman so far, but emerging threats and plans for development in the area indicate that the natural protection of its remoteness can no longer be relied upon.

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Healthy ecosystem With its vast, rich mudflats and shallow waters for feeding, and opportunities for high-tide roosting on the sabkha and sand banks, Barr Al Hikman provides the combination of food and safety that is required by shorebirds. But birds are far from being the only treasure of Barr Al Hikman, as it supports mangroves, seagrass, algae, sea snails, clams, worms, squid, crabs, shrimps and fish, all interconnected with other organisms into a rich food web. This rich ecosystem not only allows there to be a varied birdlife, but also provides important benefits to people. For example, Barr Al Hikman is a nursery ground for economically important crab and fish species caught on the nearby fishing grounds and therefore an indispensable part of the fisheries sector in Oman. Mudflats and deeper waters are tightly connected by nutrient flows and by fish and crabs that move between these habitats. Currently, the ecosystem is complete and intact, but it is also fragile. The loss or degradation of any one of its components will impact the integrity of the system and could greatly reduce its value, for both people and nature.

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Conservation and wise use The importance of Barr Al Hikman for local people, regional fisheries and global biodiversity is well recognized in Oman and the site has therefore been declared as a Wetland Reserve by Royal Decree. In addition, the large waterbird numbers at Barr Al Hikman clearly qualifies the area to be designated as a Ramsar Site – a wetland of international importance under the international convention for the conservation and sustainable use of wetlands. These are important steps in the recognition and conservation of the area. But to put this conservation status into practice we must define what actions must be taken to safeguard Barr Al Hikman for the long term. A practical management plan for conserving the area is now required: it should be based on a sound understanding of the functioning of the ecosystem and should be developed in collaboration with all the local stakeholders. We can start to tackle some of the challenges today, if only on a small scale. Plastic pollution along the coastline, for example, is a big problem. Plastic clean-up is a straightforward intervention that can start right away and that many stakeholders can contribute to, from individual visitors to companies, as well as the government. Raising awareness about Barr Al Hikman and its value is another way to promote sustainable use of the area’s rich resources. Creating support for conservation may ultimately maintain this wetland gem, and ensures that current and future generations continue to use it sustainably.

The green line on this satellite image of Barr Al Hikman shows the boundary of the Al Wusta Wetland Reserve. More information can be found at: https://meca.gov.om http://www.omanbarralhikman.org

SAFEGUARDING THIS PARADISE

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The essence of conservation is not the protection of nature against human development but the preservation of life-supporting systems and processes as the foundation of a sustainable future, in which human development is included. Inspired by Luc Hoffmann, co-founder of WWF (World Wide Fund for Nature) and architect of the Ramsar Convention on Wetlands and of Wetlands International.

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Barr Al Hikman - Shorebird paradise in Oman  

In a region dominated by arid landscapes, Barr Al Hikman is a wetland pearl. An oasis for nature that is intricately connected to its histor...

Barr Al Hikman - Shorebird paradise in Oman  

In a region dominated by arid landscapes, Barr Al Hikman is a wetland pearl. An oasis for nature that is intricately connected to its histor...

Profile for tvgdesign
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