Bird Families of the South Pacific

1 Lab Island Biogeography Part A: Bird Families of the South Pacific 1) The Number of Bird Families in Each Island Group Tonga and Samoa - 19 Solomon Islands - 38 Vanuatu and New Caledonia - 29 New Guinea - 55 New British and Bismarck- 43 Marquesas' and Pitcairn - 9 Fiji -23 Cook and society -12 2) Major Features of The Bird Family Distribution in the Islands The distribution of birds in the south pacific can be described as being near threatened, endangered, critically endangered, vulnerable, extirpated, and introduced species. The birds found in the south pacific islands are flightless. These birds present with strong legs. Only a few bird species are found on all islands. Notably, only New Guinea appears to have all specifies of birds found in the south pacific islands.

3) Distribution pattern: 3a) Evidence for the Evolution of Distinct Families on Any group of South Pacific islands There is evidence for the evolution of distinct bird families in the South Pacific islands. Evidence shows that most of the bird species in this region have evolved smaller flight muscles. These birds also have long strong legs. Evolution to flightlessness is irreversible. It involves the loss of muscle mass and the development of muscles in the hind limbs (Wright, Steadman & Witt,

2 2016). The evolution of button quail in Solomon Islands for instance is a typical demonstration of how birds evolved towards flightlessness. These evolution changes are attributed to the scarcity of avian predators as well as response to increasing insularity (Wright, Steadman & Witt, 2016). This indicates that the bird species in south pacific islands evolved towards lightlessness even though some remain Volant.

3b) Evidence of Significance of Dispersion in Bird Family Distribution Evidence has revealed that dispersion plays a vital role in the distribution of bird family. Wright, Steadman and Witt (2016) noted that the predictable shifts in the morphology of bird species may reduce their physical ability to flee via flight subsequently diminishing their potential to diversify through dispersion. The dispersion of birds is based on their relationship with the natural habitat. Large numbers of certain bird species are found in certain islands than others 3c) Dispersion Aspects of Various Bird Families Some bird families comprise of better dispersers than others. This is based on the fact that some birds adapt to a wide range of environments better than other species. The dispersion of various birds species can be categorized as uniform, random on clumped. Birds that display the clamped pattern are poor dispersers (Wright, Steadman & Witt, 2016).

3d) Factors influencing or Inhibiting the Migration of Bird Families The migration of birds is either facilitated or inhabited by a variety of factors. For instance, the absence of avian predators hinders the migration of birds. Habitat attributes and weather conditions are also significant factors that influence the migration of birds (Wright, Steadman & Witt, 2016). The availability of food, vegetation, water, suitable microclimate, and limited competition in a particular region may also hinder the movement of birds of that region.

Part B: 1- Island Areas (km2) against the Number of Terrestrial Mammal Species

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Area against number of terestial mammal species 20 15 Area against number of terestial mammal species

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area (KM2) 2. The Distance of the Islands from the Mainland (km) against Mammal Numbers

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3. Distance from the Mainland (km) against the Number of Mammal Species

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4 Distance from the mainland seems to be the most suitable variable for determining the number of terrestrial mammal species present on the islands. Data shows that the number of terrestrial animals is high closer to the mainland as compared to places far away from the mainland. The area size is an inappropriate strategy of determining the number of terrestrial animals since data shows that some huge areas have few animals and vice versa.

5 References Wright, N. A., Steadman, D. W., & Witt, C. C. (2016). Predictable evolution toward flightlessness in volant island birds. Proceedings of the National Academy of Sciences, 113(17), 4765-4770.