1902.] F. Finn — Abrupt Variation in Indian Birds. 83 



3rd (Reg. No. 24024) is also similar, but has the back of the neck 

 normal; one, procured on February 22nd (Reg. No. 24019) has the 

 head normal and the neck white all round ; and a rather small specimen, 

 obtained on February 11th (Reg. No. 24008) has the neck all white 

 in front and the head and back of the neck merely mottled with white. 



This nearly approaches the normal form, in which the fore-neck 

 shows a varying amount of white ; but any white on the crown or nape 

 may fairly be called an abrupt variation. 



I have not this year been able to procure any specimens of this 

 variety in good enough condition to keep alive, but early last year I was 

 more fortunate, and got two pairs, most of which are still living in the 

 Alipore Zoological Garden. Both males much resemble the mounted 

 male figured, but one has some tertiaries white in both wings at the 

 present time, though when obtained it only showed white in one wing. 

 The one female which remains alive merely has the neck white all round. 



During last winter I remember seeing one male largely white-necked, 

 which was dead, and I therefore did not bay it, not then attaching so 

 much importance to the variety, as I had seen so few. 



It is only during the last two winters that I have taken special 

 notice of this species, but I could not very well have overlooked the 

 conspicuous white-headed form had it occurred commonly before ; and 

 it is to be noted that these last two winters have been noteworthy for 

 unusually numerous occurrences o c the Bronze-capped Teal (Eunetta 

 falcata) in the Bazaar, a bird usually decidedly rare in India. It is 

 possible, therefore, that these white-headed Ruffs are an Eastern strain, 

 which, like the duck above-mentioned, only occasionally migrate in a 

 westerly direction. It will be noticed also that during the years 

 1842-46 thatBlyth procured his specimens, he also got the Clucking Teal 

 (Nettium formosum) and Eastern White-eyed Pochard (Nyroca baeri), 

 also eastern irregular visitants to our empire. 



As out of so many specimens of this variety seen by me only three 

 were females, we may conclude that the variation is largely limited to 

 the male, Reeves here at all events being much more numerous than 

 Ruffs. I have above shown that it only occurs in old birds, and thus 

 I am inclined to look on it as a species of senile albinism analogous 

 to what occurs in black varieties of the domestic fowl and duck. I 

 have also seen an ageing green Canary turn largely yellow about the 

 head. 



At the same time, these white-marked individuals are not at all 

 wanting in vigour ; the two white-headed males at the Calcutta Zoologi- 

 cal Gardens have survived while all the normally coloured Ruffs pro- 

 cured that winter (1900-01) have died, though kept under similar 



