NATURALIST'S CALENDAR FOR DECEMBER.
Birds.—On the 10th grouse shooting ends. The ptarmigan (Lagopus mutus) has now assumed its pure white winter livery, and all the waders are now in full winter plumage. The various species of gulls often visit inland districts at this season of the year, and in company with rooks, follow the plough in search of woi-ms and the grubs of the cockchafer (Melolontha vulgaris). The golden plovers assemble in im- mense flocks on commons, and in open fields, and if the weather proves severe, the fieldfares, redwings, and other species, descend to low marshy districts, where they find a sufficient supply of various insects.
Insects. — But very few insects are to be found in this month, though some of those which appeared last month may still be taken, if the weather is mild. — Henry Doubleday; Naturalist's Almanack for 1845.
Nidification of some Australian Birds.—On looking over vol. iii. of 'Audubon's Ornithological Biography' a few days ago, I was struck with the great difi'erence be- tween the account there given of the nidification of the booby, gannet, and two species of tern, and my own notes on the same subject made in 1844 and 1845 on the north and north-east coasts of New Holland. The birds I allude to are the Sula fusca, Anous stolidus, and Thalassipora fuliginosa. Of the brown booby of North America, Audubon states, "In all the nests which I examined, only one egg was found, and as most of the birds were sitting, and some of the eggs had the chick nearly ready for ex- clusion, it is probable that these birds raise only a single young one, like the common gannet or solan goose," p. 64. Among the numerous nests of the booby on Bramble Cay, Torres, Straits, in every instance I found two eggs, one usually much soiled, and the other quite clean. According to Audubon, in the Tortugas, the nests of the noddy contained three eggs each, p. 516. On Raine's Islet and Bramble Cay I never found more than a single egg or young bird in one nest out of many thousands which I must have seen, and the same had been previously observed by Mr. Gilbert on Houtman's Abrolhos, off the west coast of New Holland, (see 'Annals and Mag. of Nat. Hist.' vol. xiv. p. 450). Again, with regard to the sooty tern, Audubon mentions (p. 266) that it "always lays three eggs as its full number," and moreover that "there is less diflference between their eggs than is commonly seen in those of water birds, both with respect to size and colouring." On the other hand I have invariably found the sooty tern to lay only a single egg, which, besides exhibited such differences in the size and distribution of the markings, that a series of a dozen or more between those covered with large blotches and others with faint markings, with all the intermediate gradations, might easily be picked out. The circumstance thus briefly related, natu- rally led me to speculate on the probable causes of such marked differences in nidifi- cation, and 1 am inclined to adopt the easiest mode of accounting for them, by at once cutting the Gordian knot, and questioning the specific identity of the Australian and American species, although Mr. Gould, our first authority on the subject, has failed to detect any specific distinctions after a careful examination of specimens from both countries. This appears to be a case for the decision of the comparative anatomist, who, in the present state of the question, alone can set the matter at rest. — John MacGillivray; Old Aberdeen, September 25th, 1846.
