128 MEMOIRS OF THE NUTTALL ORNITHOLOGICAL CLUB. 



green bills, brown legs, and buffy throats were both females. Four of the red- 

 legged, yellow-billed birds had small irregular patches of black feathers on their 

 throats. These patches I took to be evidence of Mallard blood. In examining 

 Black Ducks, I have often had considerable difficulty in deciding to which form 

 a bird belonged. There are all gradations in the color of the bill from yellow 

 to green, and in the legs from bright red to dirty brown. The size of the birds 

 also varies greatly. The thickly spotted throat is generally associated with large 

 birds and red legs, but I have examined several birds that were typical of obscura 

 with the exception of the spotted throat. 



Mr. Hardy, whose experience in handling Ducks in the market is a con- 

 siderable one, tells me that he always classes the typical red-legged birds as old 

 males. The large shaggy heads and the tough frames and flesh lead him to 

 this belief. 



Assuming, for the sake of argument, that rubripes is merely the adult male 

 of obscura, it is interesting to note the similarity in seasonal distribution, between 

 these two forms and the adult male Red-breasted Merganser as compared with 

 the very differently plumaged females and immature. In both cases the small, 

 obscurely dressed birds come first during the early autumn, while the large 

 showy birds come in late September and in October. In both, these large birds 

 are abundant in the winter, and the smaller ones are less common, while in 

 both, the two forms appear again in the spring. The remark of Dr. Phillips 

 (anted) that " the first flight of Black Ducks consists mostly of young and 

 often imperfectly feathered birds " is interesting in this connection. These 

 observations are of course insufficient for definite deductions, and are offered 

 merely as a contribution to the study of the subject. I have made no observa- 

 tions on the adult male breeding bird in summer in Essex County, and as far as 

 I know this has never been done. Its value in the discussion is obvious. 



The recognition of rubripes in the field has already been spoken of under 

 obscura. 



Hybrids between the Black Duck and the Mallard are not uncommon. 

 There are two of these in the collection of the Peabody Academy, both from 

 Ipswich, one dated March 20th, 1883, a male, the other March 20th, 1893, a 

 female. Out of twenty-five Black Ducks from Essex County, I found, as 

 mentioned above, four which seemed to show evidence of Mallard blood. 



