HERONS, BITTERNS, ETC.: LEAST BITTERN 
97 
nuptial plumes and blatant vocal performances. When, in a tule 
marsh, on taking alarm he strikes his favorite attitude, pointing his long 
bill skyward, the light stripes of his head and neck, as Abbott Thayer 
says, imitate the bright reed stems, while the dark stripes picture the 
“reeds in shadow or the shadowed interstices between stems.” So 
great is his evident trust in his statutesque pose that he has been known 
to hold it for something like an hour in a tree on the Boston Common, 
in plain sight of all passersby. In one recorded case he apparently felt 
himself so well camouflaged that he actually feigned death, allowing 
himself to be picked up. His resources seem endless. When a breeze 
sets the cat-tail flags around him “rustling and nodding,” Mr. Barrows 
says he sways gently from side to side in unison with them, when the 
breeze subsides becoming rigid again (1913, p. 189). 
But while thus perfectly adapted to his environment and safeguarded 
in his own person by voluntary poses and movements and by a dress 
the plainness of which verges on the homely, the attention of his pros¬ 
pective mate is presumably held and the perpetuation of the species 
assured by the development of beautiful snowy nuptial plumes, shaken 
from their brown concealment in dazzling display during the strange 
rivalries of courtship. Here again attitude and plumage work together, 
for, as Mr. Brewster discovered, the ordinary erect position is exchanged 
for a low crouching attitude that makes the birds resemble pheasants 
or grouse more than herons, and throws the white wing-like nuptial 
tufts into conspicuous relief. 
As if this remarkable coordinated development of plumage and 
attitude were still inadequate to her purposes, nature has worked out a 
strange vocal specialization, the skin of the Bittern’s neck becoming 
“much thickened and of a gelatinous texture, as in the necks of the 
various grouse that boom, so that it serves as an elastic bellows,” 
producing sounds that variously represent stake driving and the work¬ 
ing of a creaking wooden pump, from which the bird is known locally as 
Stake Driver or Thunder Pumper. 
Additional Literature.—Bent, A. C., U. S. Nat. Mus. Bull. 135, 72-84, 1926. 
—Brewster, William, Auk, XXVIII, 90-100, 1911 (display of plumes).— Chapin, 
J. P., Auk, XXXIX, 196-202, 1922 (booming).— Fargo, W.G., Auk, XLV, 203-204, 
1928 (courtship).— Forbush, E. H., Birds of Massachusetts, I, 315-321, 1925.— 
Pearson, T. G., Educational Leaflet 130, Nat. Assoc. Audubon Soc.— Rockwell, 
R. B., Condor, XIV, 117-119, 1912.— Thayer, G. H., Concealing-Coloration in the 
Animal Kingdom, 56-57, 1909.— Toiirey, Bradford, Auk, VI, 1889, 1-8; Everyday 
Birds, 69-81, 1901 (booming). 
LEAST BITTERN: Ixobrychus exilis (Gmelin) 
Description. — Length: 12-14.2 inches, wing 4.3-5.2, bill 1.6-1.9, tarsus 1.5- 
1.7. Adult male: Croivn , back and tail glossy greenish black; back of neck and 
patch on wing, brown; throat white, underparts buffy, with dark brown patch each 
