Letters, E.vtracts, Notices, ^c. 573 



occurred three times in Suffolk, and I can answer for the first 

 one, it being in my father^s collection^ while a fourth was shot 

 at Embletou, in Northumberland, in December 1829, and a 

 fifth in Norway (c/. Ibis, 1884, p. 346). These may have 

 been, as good authorities believe, real examples of C. adamsi, 

 which had come over from America ; one cannot prove that 

 they were not so ; but there is another and an alternative 

 theory, which is now put forward with diffidence, to account 

 for their presence here. 



It is evident that occasionally, under circumstances un- 

 known to us, almost any kind of bird can, and does, throw 

 out some of the distinctive colours of an allied species, re- 

 verting to some ancient epoch when it had not separated 

 itself from that species, which it now, by a " sport,'^ as it 

 were, again resembles. Besides the Divers (C glacialis), 

 five other cases occur to my mind, all relating to species 

 the specific distinctness of which is generally unquestioned, in 

 which this form of imitation seems to have happened. These 

 I will briefly run over. They may all be described as recent 

 candidates for admission to the list of British birds, and 

 three of them are taken notice of in the List compiled by the 

 Committee of the British Ornithologists' Union. 



In 1861 an example of Picus major, obtained in Shetland, 

 varied so as to resemble P. leuconotus, and was even figured 

 as such in Gould's ' Birds of Great Britain,' though it was 

 proved afterwards by Professor Newton that it could not be 

 of that species (Zoologist, 1881, p. 399) . 



In the ' Zoologist ' for 1886, p. 478, Mr. Gunn records a 

 Greater Spotted Woodpecker {Picus major), with "a few 

 scarlet feathers on its chest," obtained in Norfolk. This 

 was clearly an appraximation to the Algerian Woodpecker 

 {Picus numidicus) , but there is no reason to think that it was 

 really one of that species. The pectoral band was not distinctly 

 red enough for that, even if it had agreed precisely in every 

 other way. It is equally unlikely that Picus numidicus would 

 ever fly over from Northern Africa to Germany, where the 

 supposed occurrence of this species near Miinster is easily 

 explained by the theory of variation on the part of its near 

 ally, P. major. 



