656 SYSTEMATIC SYNOPSIS. —HERODIONES-— HERODILI. 
There are about seventy-five species, very @@M@rally distributed over the globe, but especially 
abounding in the torrid and temperate zones. Those that penetrate to cold countries in 
summer are regular migrants; the others are generally stationary. They are maritime, 
lacustrine and paludicole birds, drawing their chief sustenance from animal substances taken 
from the water, or from soft ground in its vicinity; such as fish, reptiles, testaceans, and 
insects, captured by a quick thrust of the spear-like bill, given as the bird stands in wait 
or wades stealthily along. In conformity with this, the gullet is capacious, but without 
special dilatation, the stomach is small and little muscular, the intestines. are long and ex- 
tremely slender, with a large globular cloaca and a cceecum. Herons are altricial, and 
generally nest in trees or bushes (where their insessorial feet enable them to perch with ease), 
in swampy or other places near the water, often in large communities, building a large flat 
rude structure of sticks. The eggs vary in number, coincidently, to some extent, with the 
size of the species; the larger herons generally lay two or three, the smaller kinds five or six ; 
the eggs are somewhat elliptical in shape, and usually of an unvariegated bluish or greenish 
shade. The voice is a rough croak. The sexes are nearly always alike in color (remark- 
able exception in Ardetta) ; but the species in which, as in the Bittern, the plumage is nearly 
unchangeable, are very few. Indeed, probably no birds show greater changes of plumage, 
with age and season, than nearly all the herons. Their beautiful plumes are only worn 
during the breeding season; the young invariably lack them. There are still more remark- 
able differences of plumage m many cases, constituting dichromatism, or permanent normal 
difference in color, like that of the ‘‘ red” and ‘‘ gray ” specimens of Scops Owl. Thus, some 
species are pure white at all ages and seasons, in both sexes, other individuals of the same 
species bemg variously colored. Such dichromatism appears in our Ardea occidentalis, Di- 
chromanassa rufa, and Florida cerulea. It was formerly believed in the cases of the two 
latter, that the white were the young, the colored the adults; but it now appears that the 
difference is permanent, and independent of age, sex, or season. Many species are pure white 
” more particularly belongs; but I should 
at all times, and to these the name of ‘ egret 
correct a prevalent impression that an egret is anything particularly different from other herons. 
The name, a corruption of the French word ‘‘aigrette,” simply refers to the plumes that 
ornament most of the herons, white or otherwise, and has no classificatory meaning; its 
application, in any given instance, is purely conventional. The colors of the bill, lores, and 
feet are extremely variable, not only with age or season, but as individual peculiarities ; some- 
times the two legs of the same specimen are not colored exactly alike. The 2 is commonly 
smaller than the g. The normal individual variability in stature and relative length of parts 
is very great; and it has even been noted that a specimen may have one leg larger than the 
other, and the toes of one foot longer than those of the other —a circumstance perhaps result - 
ing from the common habit of these birds of standing for a long time on one leg. 
The North American Ardeide, if not the whole family, are divisible into the two subfamilies 
of Ardeine, or Herons proper, and Botaurine, or Bitterns. 
Analysis of Subfamilies, Genera, and Subgenera. 
BorauRIN»%. Tail-feathers 10. Two pairs of powder-down tracts. (Bitterns.) : 
Very small; length about a foot. Sexes unlike . . . . . . +--+ ++: 2. + « Ardetta 267 
Medium sized; length about 2feet. Sexesalike . . SPE, Gat on, 5c see « « Borawrug 266 
ARDEIN®. Tail-feathers12 Three pairs of powder-down tracts. (Herons.) 
Bill stout and comparatively short, not longer than very short tarsus, which is not perfectly scutel- 
late in front. (Night Herons.) 
Gonys convex, like the culmen; tarsus longer than middle toeandclaw . .. . . Nycterodius 265 
Gonys about straight; tarsus about equal to middle toe and claw .... . . . Nyetiardea 264 
Bill ordinary. Tarsus scutellate in front 
Length under 20 inches. Tarsus about equal to middle toe and claw. Green . .. . Butorides 263 
Length over 20 inches, under 30. Blue, white, or variegated. 
Blue or white. Adult without decomposed feathers onback. . - .., .., . » Florida 262 
