Written by Salim Ali and Laeeq Futehally
Published by National Book Trust, New Delhi
Think of birds and you think of Dr. Salim Ali, India’s most famous ornithologist. He is the scientist who succeeded in communicating his passion for studying bird life in India to the ordinary Indian.
Generations of Indians have grown up on his wonderfully warm and crisp writings on birds and have squealed in delight on being able to distinguish a red turtle dove from a spotted dove. Those who have accepted him as a guide have been able to explore the complex societies that nature’s feathered creatures have created – as complex as human societies.
In the chapter on reproduction, Salim Ali and co-author Laeeq Futehally, ardent nature lover and writer, give a vibrant account of the most important event in a bird’s life – the process of building a nest in order to breed and bring up a family.
Excerpts from the book:
For all birds, bringing up a family successfully is the most anxious business of the year, fraught with hazards and dangers, which are of course increased when a long migratory journey precedes the nest-building.
A nesting bird family is in an extremely vulnerable position, and it needs every kind of help and protection from its environment. The birds need cover in which to hide the nest; they need building material; they need warm weather, first for the protection of their eggs, later their chicks; they need a plentiful supply of food for the chicks and, lastly, long daylight hours in which to search for food.
On the whole, the most important item is the food supply. Birds will choose a nesting season when they can be sure of a liberal supply of food even if it is a little inconvenient in other ways.
This is illustrated by the small birds, which nest in a Bombay neighbourhood during the monsoon. It seems amazing that they should choose to build their frail nests at a time when they are in constant danger from lashing winds and rain.
But the insects and worms, which make their appearance at this time, all ready to be eaten, more than outweigh the danger of being washed away…
Each species, then breeds in just that season when it can be assured of an optimum food supply and when the surrounding conditions are least inimical. The physiological readiness for breeding seems to be geared to the right season.
Many birds are known not to breed at all when weather conditions are not to their liking. The flamingo, which breeds in the Rann of Kutch after the monsoon, is very particular about waiting for the right conditions. In some years, when the rainfall has been too heavy or too slight, it refuses to nest at all.
As their breeding season approaches, the males put on their breeding plumage. This may be a fine lot of new feathers, or an extra patch of colour, as in the case of the cattle egret, which acquires an orange tinge on the head and neck, or it may simply be that the existing feathers are renovated to give the owner a spruced look.
At the same time, most males also acquire a song or, at least, add a few extra sounds to their workaday calls. Song is not to be confused with the usual call notes, which are used during the rest of the year, chiefly for maintaining contact between individuals.
The special song, which is developed at this time, is a definite instrument to be used in the business of breeding. It has been found that some of the most beautiful songsters have been given their voice for a serious purpose, i.e., in order to assert their possession of, and warn rivals to keep away from their nesting territory; whereas it used to be thought that the main purpose of birds’ songs was to attract a female.
While it is not known whether the quality of a male’s singing can influence the choice of a mate, it is true that that song advertises the presence of an unattached male who has marked out a territory for himself and is only waiting for the right mate in order to start building a nest.
Because of the limited availability of food in any given area, the smaller songbirds know that more than one family cannot be raised within that area. The males, therefore, select a certain territory, and fight off any other males who intrude into it.
The loud song is the most powerful weapon in their armoury. In the breeding season, even those birds which cannot sing in any manner, develop some kind of an extra noisiness: thus the storks which have no vocal muscles manage to make a clattering noise with their mandibles.
Most birds have some kind of courtship display when the male seeks to win the female’s heart and hand. The peacock’s dance is well known, and he uses it indiscriminately to impress anyone, whether birds or man, who happens to be looking on, and often even when no one is looking!
The roller tumbles and turns somersaults in the air in a series of clever antics before a watching female, while parakeets posture and pose ludicrously, standing first on one foot then on the other, some male birds simply keep showing off their special brilliant plumage to the females in a flamboyant series of posturing and strutting, while some conduct their courtship in a quiet discreet manner.
With some birds, as in the case of the bayas, the act of building a nest is itself a form of courtship and the female chooses as mate the bird whose nest happens to catch her fancy. In many species, the offering of a worm or some other tit bit is a part of courtship, and the female often takes full advantage of the male’s ardent mood to beg for delicacies from him.
The next stage is for the pair, or in some cases, only the male or the female of the pair, to set about building a nest. As a general rule, birds build their nests in the sort of surroundings in which they are accustomed to live.
An eagle, accustomed to living at great heights, will build among the leaves of trees; birds, like partridges and quails, which spend much of their time on the ground, lay their eggs on the ground; birds, which live on the water like cormorants and herons, will build near the water, and so forth…
In the shape and structure of the nests themselves, there nests a tremendous diversity. Some of the ground birds simply scrape a little earth to one side and lay their eggs in the depression; at the other extreme is the well-known, compactly woven baya’s nest which is an elaborate affair with an inner egg chamber, which is as carefully worked as if it were made by an expert basket weaver.
Some birds nest in an old hole in a decayed branch or wall, which they line with soft materials, some dig tunnels, and some build cups of grasses in branches. Some water birds, like the jacanas, build their skimpy nests on the floating leaves of water plants.
strangely enough, it is often the larger and less vulnerable birds like the storks, herons and egrets, which build in colonies, while the small and gentle passerines like tailorbirds, wren-warblers and robins build singly and rely on camouflage.
One possible explanation is that the smaller birds are unable to cover long distances in search of food and need to be assured that there will be no rival for the food supply nearby. The bigger birds on the other hand are far ranging and can look for food farther afield, so the presence of a rival food hunter is not important for them…