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29 Water temperatures influence food production. Invertebrate production in the water column may ultimately depend on the water temperature and the ability of a wetland to produce algae. Cold water might not be a very hospitable environment for small animals and plants that some wetland birds eat. However water that is too warm also might not produce foods that some birds prefer. Many bird species use forested wetlands as well as forested uplands, feeding on the abundant insects associated with trees. These birds are not dependent on wetlands because they use both habitats equally well. Some birds, such as wood ducks, are found primarily in forested wetlands and are dependent on this wetland type. Wetland vegetation provides shelter from predators and from the weather. The presence or absence of shelter may influence whether birds will inhabit a wetland or a nearby upland area. Predators are likely to abound where birds concentrate, breed, or raise their young. Wetlands form an important buffer or barrier to land-based predators and reduce the risk of predation to nesting or young birds. However, some predators are well adapted to both wetland and upland environments, and take large numbers of both young and nesting birds. Some forage for nesting or sleeping birds along the edges and interiors of wetlands. Other animals, such as the snapping turtle, the alligator, are effective waterbased predators of young birds, particularly young waterfowl. Snakes take their toll as well. Many bird species that are highly adapted to feeding in a wetland environment also have genetic adaptations that lower their risk of becoming prey. One such example is the bittern which has excellent protective

coloration. The same vegetation that hides birds from predators also provides some shelter from severe weather. During cold and stormy weather, waterfowls, ducks protect their young in the shelter of a marsh that is almost impenetrable to wind. Some wetlands are on the migration path of waterfowls and other migratory birds and provide stopover locations for travelling birds. These birds travel each year between their breeding grounds in the northern hemisphere and nonbreeding habitat. Migratory shorebirds inhabit the shorelines of rivers, wetlands, oceans and lakes, where they need to rest and feed during their non-breeding season (SeptemberMarch) to prepare for their annual migrations to breeding grounds in the Arctic. .Some of these birds might feed in agricultural fields during the day and return to the shelter of wetlands during the night. India is a signatory to the Convention of Migratory Species and must ensure safe passage for all migratory birds. Though considerable research has increased the understanding of wetlands’ influence on the numbers of waterfowl that breed and their breeding success. However, the relation between wetlands and the population and propagation of various waterfowl species is not well understood. This relation depends on: (1) the number of wetlands in the area; (2) the wetlands’ size and water depth; (3) whether the wetlands hold open water in the early spring or through late August (4) the climate and (5) the species of bird and the bird’s adaptations to wetlands. Photo courtesy Avinash Bhagat

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Aapala Paryavaran Magazine February 2016

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Aapala Paryavaran Magazine February 2016

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