Birds of the Plains

by Douglas Dewar

Otocompsa is a more showy bird. The crest is long and projects forward over the forehead. The crimson patch, so characteristic of bulbuls, also exists in this species. There is a similar patch on each side of the head—whence the bird’s name, the red-whiskered bulbul. There is also a white patch on each cheek. The white throat is separated from the whitish abdomen by a conspicuous dark brown necklace. This bird must be familiar to every one who has visited Coonoor or any other southern hill station. The less showy variety—the red-vented bulbul, as it is called—is common in and about Madras.

It will be noticed that I have refrained from giving any specific name to either of these two genera. This is due to the fact that these bulbuls are widely distributed and fall into a number of local races, each of which has some little peculiarity in colouring. For this reason, bulbuls are birds after the heart of the museum ornithologist. They afford him ample scope for species-making.

THE BENGAL RED-WHISKERED BULBUL. (OTOCOMPSA EMERIA)

If you go from Madras to the Punjab you will there meet with a bulbul which you will take for the same species as the bulbul you left behind in Madras. But if you look up the birds in an ornithological text-book you will find that they belong to different species. The Punjab bulbul is known as Molpastes intermedius, while the Madras bird is called M. hæmorrhous. The only difference in appearance between the two species is that in the Madras bird the black of the head does not extend to the neck, whereas in the Punjab bird it does. Similarly, there is a Burmese, a Tenasserim, a Chinese, and a Bengal red-vented bulbul.

Now, I regard all these different bulbuls as local races of one species, which might perhaps be called Molpastes indicus; and I think that I am justified in holding this view by the fact that the bulbuls you come across at Lucknow do not fit in with the description of any of these so-called species. The reason is that the Bengal and the Madras races meet at Lucknow, and of course interbreed. The result is a cross between the two races.

In addition to the above there are some Molpastes which have white cheeks and a yellow patch under the tail. In all, nine or ten Indian “species” of Molpastes have been described.

The same applies in a lesser degree to Otocompsa. This is a widely distributed species, but is not so plastic as Molpastes. There is the Bengal red-whiskered bulbul (Otocompsa emeria), which is distinguishable from the southern variety (O. fuscicaudata) by having white tips to the tail feathers, and the dark necklace interrupted in the middle. There is also an Otocompsa with a yellow patch under the tail.

This division of a species or genus into a number of races or nearly allied species is interesting as showing one of the ways in which new species arise in Nature quite independently of natural selection. It is unreasonable to suppose that the extension into the neck of the black of the head in the Punjab bulbul and its non-extension in the Madras bulbul are due to the action of natural selection in each locality, that a bulbul with black in its neck is unfitted for existence in Madras.

Whenever a group of animals becomes isolated from its fellows, it almost invariably develops peculiarities which are of no help to it in the struggle for existence. Thus isolation is the cause of the origin of dialects and languages. A dialect is an incipient language, even as a race is a potential species.