Usgs bird population

USGS Bird Population Introduction The generalists species of birds are known to be more widespread and distributed uniformly more than the specialists species of birds. The specialists have a narrow range of environmental tolerance and have minimal diets preferences. More so, their preference of narrow niche is the main reason why they are not widely distributed as the generalists’ species. The climate range of the different species of birds like precipitation and the biome is also another reason as to why they are differently distributed. Therefore, this paper will use the generalists and specialists species characteristics to determine where the Double Crested Cormorant, Great Blue Herron, Wood Stock and the American Robin belong (Mobley 12).
Double Crested Cormorant
This specie of bird is a specialist. The Double Crested Cormorant is mostly distributed along the coastal regions and water bodies like the Gulf, Pacific and the Atlantic coasts in Canada and the United States which are densely populated due to the economic activities that are carried out in these regions (Sauer 2). It is also found along the Great Lakes and Mississippi valley. Their breeding nests are usually built on top of very tall trees in areas with bodies of water; therefore, they thrive best in wetland biomes. They change their niche according to the precipitation available at a particular time mostly preferring regions with high precipitation. The Double Crested Cormorant is very specific with its diet. It mainly eats fish and this is the reason why it prefers areas near water bodies. They mostly thrive in the riparian habitats. They are widely spread in water body regions but more uniformly distributed in regions that have water masses. Their diet which mainly consists of fish gives evidence that they are specialists and not generalists (Mobley 12).
Great Blue Heron
This specie of birds is generalists. This is because of their wide range of distribution. Although they are mainly distributed along northern America, Mexico and southern Canada, they are more common throughout the United States apart from regions that are woody (Sauer 2). They prefer the summer as opposed to winter seasons and this is why they are mostly found in Minnesota during summer. They are found in both coniferous and deciduous forests. They can also be seen in swampy areas or areas near water bodies. In addition, they can thrive in tree habitats that are either dead or alive and also found in densely populated areas. This means that they can survive in any environmental niche be it forested, savannah or wetlands. Another major reason why they are generalists is that they are not as specific with diet like the Double Crested Cormorant. This is because, they can eat fish, small mammals, nestlings and even human food scraps. More so, they are widespread in the regions they are found most but less evenly distributed (Mobley 12).
Wood storks
This specie of bird is a specialist. It is founds mainly in southern region of the United States, the east of Andes and northern Argentina (Sauer 2). This specie of bird mostly thrives in areas that have moisture like swampy regions, freshwaters and the brackish wetlands therefore its biome is the wetland regions. They would rather be in areas that are isolated with less density of another population or community and thus their less widely spread in most of the regions. They mainly feed on fish and this is the reason why they are always found in regions that have at least some water body, hence, this enhances the reason why they are specialists and not generalist (Mobley 12).
American Robin
It is a generalist’s specie of bird. It is very common specie since it thrives in both summer and winter. They are mostly found in the Northern America in regions that are treeless (Sauer 2). Their diet consists of mainly earthworms but also takes snails, beetles, caterpillars, grasshoppers, invertebrates and even fruits when not breeding. They are found in wide range of habitats including the suburban regions, forests and parks. They thrive well near densely populated region and prefer mostly open forests with short trees like the savannah region. Their nests can be built in deciduous trees, shrubs, houses, conifers and even on ground which emphasizes the reason why they are generalists (Mobley 12).
Work cited
Sauer, J. R. et al. The North American Breeding Bird Survey, Results and Analysis 1966 – 2010. analysis of bird distribution. Newyork: USGS patuxent Wildlife Research Centre, 2011.
Mobley, Jason A. Birds of the World. New York: Marshall Cavendish, 2009. Print.