Birds are beautiful and are excellent indicators of environmental changes.
Birds are present throughout almost every habitat across the globe no matter where you go. Even if you cannot them, but a nest on a tree or holes pecked by a woodpecker on the bark suggests the presences of birds in the area. Even small activities done by birds have a great impact on the ecosystem they inhibit, thereby making them an important and significant part of different ecosystems they live in.
"Being widespread and highly sensitive to environment changes they are a very significant indicator of the wellbeing of our world. Their extinction also affects the other species."
One of the basic benefits is nutrient cycling and formation of soil. Birds can move nutrients from one place to another when they spread activities from one place to another, which is particularly relevant in places where plant growth is limited by nutrient availability.
Birds also stimulate primary productivity, which supports the functioning of ecosystems. For example, in Alaska when the snow geese stopover in salt marshes during spring migrations, they trample the ground for food, which tears up leaf litter and integrates it into the soil that promotes greater decomposition and thus freeing nitrogen allowing it to cycle through the ecosystem.
This is list of bird species by global population, divided by bird classification. While numbers are estimates, they have been made by the experts in their fields.Contributing organizations include the IUCN, BirdLife International, and Partners in Flight.
All numbers are estimates, because they are taken by observation, and a given number of 50 slender-billed curlews does not necessarily mean there are 10 more of this species than the black stilt, which has been estimated at 40: there is a possibility that the latter species has a larger population than the former.
Different species of birds suit different types of natural habitat. Although there is much overlap in the resources that different habitats provide (e.g. insect food), some habitats are rich in certain resources. For example, heathlands are often rich in plant species belonging to the family Proteaceae, which tend to have bird-pollinated flowers that are rich in nectar.Heathlands are therefore good places to see honeyeaters. Plants of rainforests often produce fleshy fruits and berries. Rainforests are therefore good places to find fruit-eating pigeons.
Almost every part of a bird’s anatomy has evolved in some part to enhance flight. Birds must be lightweight to fly, so have evolved very lightweight hollow bones.
The structure of their bones resembles honeycomb, making them very strong but also very light. For example, frigate birds have a wingspan of over two metres, but the skeleton weighs 113g. Birds also have fewer organs (e.g. only one ovary) and no teeth. Birds use a digestive organ called a gizzard to grind up food.
Bird conservation is a field in the science of conservation biology related to threatened birds. Humans have had a profound effect on many bird species. Over one hundred species have gone extinct in historical times, although the most dramatic human-caused extinctions occurred in the Pacific Ocean as humans colonised the islands of Melanesia, Polynesia and Micronesia, during which an estimated 750-1800 species of bird became extinct.