Vol. XXXV1I1 



1920 



I Wetmore, Birds of Lake Burford, N. Mex. 227 



General Discussion 

 Though a fair number of breeding individuals of various ducks 

 inhabit Lake Burford in summer, it seems from observation, that 

 in addition many drakes come there to molt and spend the summer 

 after their duties of reproduction are completed. Males of the 

 Cinnamon Teal, Mallard and Redhead were the first of these to 

 appear, and, though not present at the time of my departure in 

 large numbers, still it seemed that they were steadily increasing 

 in abundance. A drake Cinnamon Teal, in company with a male 

 Mallard, shot on May 27, had evidently finished breeding as the 

 plumage was worn, the penis and cloaca reduced in size and the 

 testes shrinking. On the following day six drakes of this species 

 were observed in one flock, and from then on they were fairly com- 

 mon. Male Mallards consorting by themselves or with other 

 drakes appeared May 27 and 28, and were seen in small numbers 

 until June 10, after which they were common. One that was molt- 

 ing into eclipse plumage was observed June 4. Drake Redheads 

 began to separate from the females on June 3, and after June 14 

 were common. In the case first noted of the Mallard and Cinna- 

 mon Teal drakes there can be no doubt but that they represented 

 birds that had bred elsewhere, possibly at a lower altitude (though 

 of course there is no means available for proving this) and had 

 come here afterward to molt and spend the summer. No other 

 deduction may be drawn from the facts outlined above, as at the 

 time at which they appeared females of the same species were 

 just beginning to lay at Lake Burford. The presence of such 

 unmated birds as these shows that it is unsafe to rely upon a count 

 of all drakes in arriving at an approximately correct census of the 

 breeding ducks of any given area. 1 It is true that breeding drakes 

 at certain times of the day (usually between 8 and 10 in the morn- 

 ing) are found alone, while the female is absent at the nest deposit- 

 ing an egg; and these drakes usually linger near at hand for a few 

 days after the female has ceased to lay and has begun to incubate. 

 (This statement may be qualified by adding that it is more often 



'The statements outlined here do not apply to ths Ruddy Duck {Erismatura 

 jamaicensis) as the drake of that species, like the male Canada goose, usually re- 

 mains true to his spouse during incubation and the rearing of the young. 



