Gannets do not feed, as some have supposed, and as many have believed, on herring only; for I have found in their stomachs codlings eight inches in length, as well as very large American mackerels, which, by the way, are quite different from those so abundantly met with on the coasts of Europe.
The young never leave the spot on which they have been reared until they are well able to fly, when they separate from the old birds, and do not rejoin them until at least a year after. Although I have in a few instances found individuals yet patched with dark-grey spots, and with most of their primary quills still black, I am confident that it is not until the end of two years that they acquire their full plumage. I have seen some with one wing almost pure black, and the tail of that colour also; others with the tail only black; and several with pure black feathers interspersed among the general white plumage.
I know of no other bird that has so few formidable enemies as the Gannet. Not one of the species of Lestris with which I am acquainted, ever attempts to molest it; and, although I have seen the Frigate Pelican in quest of food within a short distance of it, I never saw it offer injury. The insular rocks on which it breeds are of course inaccessible to quadrupeds. The only animals, so far as I know, that feed on the eggs or young, are the Larus marinus and Larus glaucus. It is said that the Skua, Lestris Cataractes, sometimes pursues the Gannets, but that species does not exist in North America; and I am inclined to doubt the truth of this statement, for I have never seen a Lestris of any kind attack a bird equal to itself in size and strength.
Soon after the young Gannets are able to fly, all the birds of the species leave the breeding place, and absent themselves until the following season. While at Newfoundland, I was told that the English and French fishermen who inhabit that country salt young Gannets for winter provision, as is done in Scotland; but I saw none there. In my estimation, the flesh of this bird is so bad that, as long as any other can be procured, it ought to be rejected.
It is a curious fact, that the Gannets often procure mackerels or herrings four or five weeks before the fishermen fall in with them on our coast; but this is easily explained by their extensive wanderings. Although this bird is easily kept in captivity, it is far from being a pleasant pet. Its ordure is abundant, disagreeable to the eye as well as the nose; its gait is awkward; and even its pale owl-like eyes glare on you with an unpleasant expression. Add to this, the expense of its food, and I can easily conceive that you will not give it a place in your aviary, unless for the mere amusement of seeing it catch the food thrown to it, which it does like a dog.
The feathers of the lower parts of the Gannet differ from those of most other birds, in being extremely convex externally, which gives the bird the appearance of being covered beneath with light shell-work, exceedingly difficult to be represented in a drawing.
My highly esteemed and talented friend William Macgillivray having given a full account of the habits of the Gannet, as observed on the Bass Rock in Scotland, I here present it to you.
“The Bass is an abrupt rock, having a basis of about a mile in circumference, and of an oblong form. The cliffs are perpendicular in some places, overhanging in others, and everywhere precipitous, excepting at the narrow extremity next the land, where, sloping less abruptly, they form at the base a low projection, on which is the only landing-place. Above this are the ruins of the fortifications and houses, the Bass having formerly been used as a State-prison. The rocks are in some places apparently two hundred feet in height, and the summit, towards which the surface rises in an irregular manner, is probably a hundred and fifty feet higher. In as far as I observed, the whole mass is of a uniform structure, consisting of trap, intermediate between greenstone and clinkstone, of a dull brownish-red colour, and small granular structure. Although a great portion of the upper surface of the island is composed of rock, there is an abundant vegetation, consisting chiefly of Festuca ovina, F. duriuscula, and a few other grasses, mixed with the plants usually found in maritime situations.
“The circumstance connected with the Bass most interesting to the Zoologist, is its being one of the few places in Britain to which the Gannet resorts during the breeding season. The number which I saw on the 13th May 1831, when I for the first time visited it along with some friends, might be estimated at twenty thousand. Every part of the mural faces of the rock, especially towards their summits, was more or less covered by them. In one spot near the landing place, about forty yards in circumference, and on a gentle slope of gravelly ground, about three hundred individuals were sitting in peaceful security on their nests.
“The Gannets arrive about the middle of February or the beginning of March, and depart in October; some years a few individuals remain during the winter. The nests are composed of grass and sea-weeds, generally placed on the bare rock or earth, elevated in the form of a truncated cone, of which the base is about twenty inches in diameter, with a shallow terminal cavity. On the summit of the island are numerous holes in the turf, from eight to fifteen inches deep, and from six to nine broad, formed by the Gannets in pulling away grass and turf for their nests. They are placed on all parts of the rocks where a convenient spot occurs, but are much more numerous towards the summit. Some of them on the face of the rock, or in a shallow fissure, and which have been occupied for years, are piled up to the height of from three to five feet, but in this case they always lean against the rock. The egg, which is solitary, and presents nothing remarkable in its position, is of an elongated oval form, bluish-white, dull, with a chalky surface, usually patched with yellowish-brown dirt. It is subjected to what might appear rough usage, for the bird in alighting, flying off, or when disturbed by the intrusion of human visitors, tosses it about, and often stands upon it.