Photo by Scholastic Photo. Co.] [Parson's Green.
INDIAN CATTLE-EGRET.
This is a species of buff-backed heron, and earns its name from its habit of hovering round cattle for the sake of picking off the ticks by which they are infested.
The best-known species is the Common Bittern, though this epithet is no longer applicable, for at the present time it is but an occasional visitant to Britain. Once it was plentiful enough, as the frequent references both in prose and poetry bear witness. These references have been inspired mainly by its very peculiar note, made apparently only during the breeding-season. This sound is variously described as "booming," "bellowing," and "bumping," and many are the theories which have been invented to account for its origin. Thomson, in "The Seasons," says that it is made whilst the beak is thrust into the mud:—
The bittern knows his time, with bill ingulf'd
To shake the sounding marsh.
Chaucer, that it is caused whilst it is immersed under water; and Dryden represents it as made by thrusting the bill into a reed. Mr. J. E. Harting is one of the few who have actually watched the bird during the production of the sound, and from him we gather that it is made by expelling the air from the throat whilst the head is held vertically upwards.
The protective coloration and the peculiar habits associated therewith have only recently been recognised. These birds, when threatened, do not take flight, but immediately bring the body and the long neck and pointed head into one vertical line, and remain absolutely motionless so long as the cause of alarm persists. The peculiar coloration of the body harmonises so perfectly with the surrounding undergrowth, that, as just remarked, detection is well-nigh impossible. Although the pattern and tone of the coloration vary in the various species of bittern—which occur all over the world—this principle of protection obtains in all.
The drainage of the fens is answerable for the extinction of the bittern in England.