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Show 1874.] MR. R. B. SHARPE ON CERTAIN ACCIPITRES. 581 fordshire along with the nest and eggs ; and the female of this bird wears such a curious plumage that I have thought it worthy of being brought before the notice of the Society. She is fully adult, having been, indeed, trapped on the nest, but has almost the tail of a male bird, blue with a few black bars. M y views on the relation of the British avifauna to that of the continent of Europe are, I believe, now so well known that I shall be excused for bringing forward this female Kestrel as a further evidence of the tendency of our indigenous birds to show the effects of their insular habitat, of which Parus britannicus and Acredula vagans are forcible examples. For I may as well state that m y faith in these last-named species is not in the least shaken, despite the cheers for a " conservative reaction" given by Dr. Sclater ('Ibis,' 1874, p. 173) on account of Professor Newton's refusal to recognize, in his edition of 'Yarrell,' the specific titles bestowed on the British Titmice. I am thankful to say that all the continental naturalists to whom I have shown the birds are more "liberal" in their tenets-and naturally so ; for neither Professor Newton nor any one else has yet recorded an olive-backed Coal Titmouse from the continent of Europe ; and however nearly Parus britannicus in its worn breeding-plumage may approach the blue-backed P. ater, birds killed in autumn, winter, and spring can scarcely be mistaken for that species. Returning once more to Cerchneis, I notice that the discovery of a female of C. tinnunculus with a blue tail renders invalid the characters which I have assigned to the hen C. rupicola in m y ' Catalogue of Birds;' and it therefore becomes necessary to reexamine the twro species, to establish, if possible, a permanent character between them. In Dresser's ' Birds of Europe,' when I was part author, the Common Kestrel was described and figured ; and we then had occasion to remark on the dark form of Kestrel which occurs along the southern range of C. tinnunculus, from Madeira through Senegambia to Abyssinia, in the Himalayas, China, and Japan. At p. 426 of the * Catalogue ' I again draw attention to this dark form : and I may be allowed to quote a few remarks I make there on the plumage of the female:-"Through all these dark races of Kestrel one character is predominant in addition to the richer and more intense coloration of the male bird, viz. that the female has more or less of a shade of blue on the rump and tail, which sometimes overspreads the whole of the latter." The Hertfordshire female, however, differs from those alluded to in the above paragraph in having an entirely blue tail regularly banded across with black, and the rump also blue with a few black shaft-streaks. And if any one takes this specimen for elucidation by means of the "Key to the Species" of Cerchneis (p. 423), they will find that it will appear as an adult female of Cerchneis rupicola, the South-African Kestrel, and is further closely allied to that of C. moluccensis. That a hen bird killed in England along with an ordinary male Kestrel can be either one or the other of these species is impossible ; but we may look upon it as exhibiting a tendency to vary in our indigenous species in the same way as the Madeira bird does in a more southern latitude. |
