The young bird is at first almost destitute of feathers, but scantily covered with yellowish-white down. When fully fledged, its bill and legs are greenish-black, and its plumage pure white, or slightly tinged with cream-colour, the tips of the three outer primaries light greyish-blue. Of this colour the bird remains until the breeding season, when, however, some individuals exhibit a few straggling pale blue feathers. When they have entered on their second year, these young birds become spotted with deeper blue on some parts of the body, or on the head and neck, thus appearing singularly patched with that colour and pure white, the former increasing with the age of the bird in so remarkable a manner, that you may see specimens of these birds with portions even of the pendant feathers of their head or shoulders so marked. And these are produced by full moultings, by which I mean the unexpected appearance, as it were, of feathers growing out of the skin of the bird coloured entirely blue, as is the case in many of our land birds. In all these stages of plumage, and from the first spring after birth, the young birds breed with others, as is equally the case with Ardea rufescens. You may see a pure white individual paired with one of a full blue colour, or with one patched with blue and white. The young, after leaving their parents, remain separate from the old birds until the next breeding season. At no period can the young of this species be confounded with, or mistaken for that of the Ardea candidissima, by a person really acquainted with these birds, for the Blue Heron is not only larger than the latter, but the very colour of its feet and legs is perfectly distinctive. Indeed, during the time when the young Blue Heron is quite white (excepting on the tips of the outer primaries), it would be easier to confound it with the young of the Reddish Egret, Ardea rufescens, than with that of any other, were the feathers of its hind head and neck of the same curious curled appearance as those of that species.
My friend John Bachman informs me, that in South Carolina, this species not unfrequently breeds in the company of the Louisiana Heron, the nests and eggs of which, he adds, are very similar. He has specimens of these birds in all the different stages which I have described. At New Orleans, the Blue Herons, during the transition of their plumage from white to blue, are called “Egrettes folles,” or foolish Egrets, on account of their unusual tameness. My friend Bachman and I, shot, on the 6th and 9th of April, several specimens spotted with blue feathers, and having their crests and trains similarly mixed, although of full length; but in most of the specimens obtained, the white was still prevalent. I have shot some in Louisiana, in autumn, in the same curious dress.
This species, though larger than the Snowy Heron, Ardea candidissima, is considerably inferior to it in courage; and I was much amused as well as surprised, when at Galveston Bay, on the 24th of April 1837, to see one of that species alight near a Purple Heron, attack it, and pursue it as far as I could follow them with my eyes. When the Blue Herons are on the sea-coast they not unfrequently repose on the large mud or sand bars, at some distance from the adjacent marshes; but they generally prefer roosting on trees or bushes, when there are any in their neighbourhood. The Creoles of Louisiana not unfrequently eat the flesh of this species, and although they by no means consider it equal to that of the Night Heron, some of them have assured me that it is not bad food. Like other birds of this family, they become larger with age, and the male is usually somewhat superior in size to the female; but, with this exception, no difference can be perceived in the external appearance of the sexes.
Ardea cœrulea, Linn. Syst. Nat. vol. 1. p. 238.—Lath. Ind. Ornith. vol. ii. p. 689.
Ardea cœrulea, Ch. Bonaparte, Synopsis, p. 300.
Blue Heron, Ardea cœrulea, Wils. Amer. Ornith. vol. vii. p. 117. pl. 62. fig. 3. Adult.
Blue Heron, Nuttall, Manual, vol. ii. p. 58.
Adult Male in full plumage. Plate CCCVI. Fig. 1.
Bill much longer than the head, rather slender, very slightly decurved, compressed, tapering to a point. Upper mandible with the dorsal line nearly straight for two-thirds of its length, then slightly decurved, the ridge convex, broad at the base, gradually narrowed to the point; a groove from the base to near the end, the sides convex beneath, the edges thin and sharp, with a slight notch close to the tips. Nostrils basal, linear, longitudinal, with a membrane above and behind. Lower mandible with the angle extremely narrow and elongated, the dorsal line beyond it ascending and almost straight, the sides sloping outwards, and flattened, the edges sharp and slightly inflected, the tip acuminate.
Head rather small, oblong, compressed. Neck very long and slender. Body slender and compressed. Feet very long; tibia elongated, its lower half bare, very slender, covered all round with angular scales, of which the posterior are large; tarsus elongated, slender, compressed, anteriorly covered with numerous broad scutella, laterally and behind with angular scales. Toes long, slender, with numerous broad scutella above, flattened and reticularly granulate beneath. Claws rather long, arched, compressed, acute, that of hind toe much larger and more curved, the inner edge of that of the third finely and regularly pectinate.