Now the usual question will be why a fresh water lake bird such as this Pratincole will eject salt water from its body this way. Its food stuff consists mainly of small insects hovering above the rivers or other water bodies, some insects living in the ground level, such as grasshoppers, moths, ants, flies, honeybees, Cricket and some invertebrate organisms.

Marine salt water animals are visibly absent in the list of the foods that the Pratincoles eat. In this connection we can mention the research work done by a scientist named Technau in 1936. He did his research work on 83 different species of birds and concluded that out of that 83 species of birds about 24 species had considerably large salt glands, all of whom had their habitats near the sea and were marine birds. And a more interesting thing was that the amount of salt secretion among the birds of a very same genus varied as a result of the change of place of their habitats.

The scientist Schildmacher described in his research work in 1932 that in the Berlin zoo that the salt glands of different ducks of the same species becomes larger when they live close to some saline water bodies than those of the other ducks who live in fresh water. Therefore, though the Pratincoles are generally fresh water birds as I saw them in Monglajodi, it may not be unusual for them to drink saline water from the nearby Chilika sea coast ore from some other parts of the sea.

But we cannot tell for certain that the salt glands are characteristics only of birds of saline or maritime habitat.

Active salt glands are also found in a number of birds such as Roadrunner, Savannah Hawk living in desert areas. Their nasal secretion takes place due to their habit of eating high protein food such as some insects and some vertebrate animals. The desert birds such as Sand Partridges or ostriches also have active salt glands which help them to balance the amount of salt and water in their bodies in high temperatures. This reason also might play an important role in the case of this Oriental Pratincole for its salt secretion.

Let me now come to my first point, osmoregulation. Whether a bird lives near salt water or not it continues its work of balancing the amount of salt and water in its body all the time. Perhaps this is the first time that the incidence of salt secretion by a Pratincole has been captured in the natural environment in a snapshot in the Indian Sub-continent.

Originally written in Bengali and Photography by Samrat Sarkar.
Translation into English by Biswajit Debnath.
Month of Observation - December 2016.
Technical sketch source - Internet.

Technical Papers helped to write this Article are -
1. THE FUNCTION OF THE SALT GLAND IN THE BROWN PELICAN BY KNUT SCHMIDT-NIELSEN AND RAGNAR FANGE.
2. The Salt-Secreting Gland of Marine Birds By KNUT SCHMIDT-NIELSEN, PH.D.
Special Thanks to Cornell Lab of Ornithology, USA

Comments, Inputs, Critiques are most welcome.