Birds play an important role in monitoring (informing) the environment. Every species (living creature) has its own significance and its presence or absence in a particular habitat (local environment of a group of organisms) has a specific importance.
The birds have freedom to move wherever they like and political boundaries have no meaning for them. The only thing that matters is the suitability of the environment. The birds of the Polar Regions are different from those found in the tropics or those found in the temperate regions. Similarly the hill species are different from those found in the plains.
It is noticed that the metabolic rate (pertaining to change of food into living tissues) of birds is much higher than that of humans, and as a result they suffer from pollution much before it affects humanity. Birds have a close connection with the environment.
Therefore, the birds effectively forecast an environmental set up of the region. Some birds are intentionally kept near the coal mines and in case the release of carbon dioxide exceeds the permissible limits, the birds die that forecast the danger of mine explosion.
The appearance of vultures, owls, bats, etc., are symbolic of bad weather or unfavorable environment while on the other side, the appearance of peacock is symbolic of rain, good weather and good environment. Such examination can be multiplied and reflect how the birds monitor the environment.
The sudden fall in the number of aquatic (water life) organisms due to the spraying of poisonous pesticides (killing chemicals) and other chemicals also show their close connection with the environment.
The spraying of DDT destroys the aquatic fauna (animals) on which the marine organisms depend. The fish eating birds die on account of consuming fish that are affected by DDT and / or other poisonous gases or chemicals.
When the “birds living on the banks of lakes, ponds or streams start dying on consuming the polluted water, it clearly indicates, that there are industries adjoining to these water bodies and their wastes are polluting the water. A close relationship between environment and the birds had also been established by their presence in specific regions.
The presence of parrots indicates the presence of guava and berry trees. The presence of cuckoos suggests the existence of mango trees whereas sparrows are seen near paddy field.