58 NORTHERN ZOOLOGY. 



A finely-plumaged male bird of Falco cyanens (ISOiseau St. Martin), in the 

 Paris Museum, had the proportions of the quills as follows : first equal to the 

 seventh ; the second half an inch shorter than the fifth ; the third a slight degree 

 shorter than the fourth ; which was the longest of all. The under plumage was pure 

 white, the tail hardly rounded, and the two middle feathers slightly shorter than 

 the rest. The two most adult of our male specimens (Nos. 1 and 3) very closely 

 agree in these dimensions, except, indeed, that the difference between the third 

 and fourth quill feathers is not very apparent ; but we cannot, on this account 

 alone, consider them identical, for precisely the same characters are equally appa- 

 rent in the Circus kistrionicus of Quoy and Gaimard {Basard bariole, Mus. Par.), 

 a bird somewhat smaller, and barred beneath with rufous, but in general dispo- 

 sition of colours, and length of wings and tail, closely resembling C. cyaneus. 



On the supposition that the whole of our specimens belong to one species, 

 (a fact, however, which cannot be proved,) we shall now give the relative lengths of 

 the quill feathers in what appears a young male (No. 7). First quill feather inter- 

 mediate in length between the sixth and seventh ; second equal to the fifth ; third 

 equal to the fourth, which are the longest. It thus appears that even in characters 

 upon which we may generally place some reliance, individuals of the same species 

 will materially differ. European specimens in the French Museum of Circus 

 cyaneus exhibit the third and fourth quills equal ; and this is also apparent in some 

 of those collected in America. We must, however, notice a specimen which pre- 

 sents a considerable deviation from the rest ; it is a Bear Lake specimen (No. 8), 

 killed in the autumn, and exhibits a general resemblance to the other two procured 

 there, but the colours of its plumage, deep liver-brown above and rust-coloured 

 below, are considerably darker. Its sex was not ascertained, but it was probably 

 a female, the other two being males ; and it may have been a yearling bird, not 

 above three months old, while the others, having been killed in May, must have 

 been birds at least as old as the preceding season. In it the second quill feather 

 is a very little shorter than the fifth, and an inch and three-quarters longer than 

 the sixth : the relative lengths of the other feathers correspond with No. 7, above 

 mentioned. No great stress can be laid on the difference exhibited by this speci- 

 men in the clearness and brightness of its colours, for this is generally a mere 

 indication of youth. In most of the Falconidce that are variegated, either with 

 brown or rufous, the colours are most intense in youth, and gradually become paler 

 or disappear with advanced age ; but the total absence of the festoon or obsolete 

 tooth, in the upper mandible of this bird, is somewhat remarkable. We know 

 not of any instance that would lead us to believe this deficiency to be the mere 



