40 



U. S. NATIONAL MUSEUM BULLETIN 217 



The progress of egg development in the female greater scaup, as 

 shown in the tabulation below, indicates that in 1951, eggs were ready 

 to be laid June 5 and that one female had not completed laying on 

 June 16. 



Bate (1951) 



Weight (g.) 



Length of eggs (mm.) 



Date (1951) 



Weight (g.) 



Length of eggs (mm.) 



25 May 



856 



4,2 



15 June 



1067 



8 



28 May 



918 



15 



15 June 



985 



6 



28 May 



1117 



15 



16 June 



1034 



31, 26, 17, 12, 10, 



28 May 



978 



1, 2 







8, 5,3 



28 May 



964 



4,2 



10 July 



740 



(with downy 



31 May 



992 









young) 



5 June 



1069 



(1 larger egg 

 broken) 









Young birds are often seen during the late summer accompanied by 

 females. A female greater scaup, remarked upon as containing very 

 little fat was collected at Kidgavik Lake, near the northern moun- 

 tain line in the Killik Valley on July 10, 1951 with two downy yomig. 

 These young birds, weighing 91 and 89 grams were then heavier than 

 I would expect the eggs to weigh. I would guess that they were not a 

 week old, and that the eggs from which they came had been laid early 

 in June. Young scaup, not distinguishable as to the species were 

 recorded as unable to fly on August 28, 1950, in Tuluak Lake. 



Until about mid-June, male and female birds were observed to- 

 gether, and a female, collected with a male on June 16, 1951, contained 

 eggs, the largest of which measured 31 mm. and was nearly ready to 

 be laid. Two days later two small flocks of four and six males were 

 seen on Napaktualoitch Lake and on June 28 several flocks composed 

 exclusively of from 20 to 30 males were assembled near the center of 

 Margaktuk Lake. 



The Nunamiut call the scaup Kaklufuk, meaning "big-billed." 

 Although they recognized that variations in size occurred they did not 

 distinguish between the two scaup mitil the decisive characters were 

 pointed out. They were not impressed by the difference until after 

 several years of examining and weighing the birds. Now they accept 

 the difference in size and bill as distinguishing the greater from the 

 lesser scaup. 



Aythya affinis (Eyton) 



4 males 



May 27- June 4 



weight (3), 769, 681, 

 694 g. 



4 females 



May 29-Sept. 10 



weight (2), 601, 651 



(thought to be 





g. 



of this form) 







1 large downy 



Aug. 7, 1950 



weight 350 g. 



male 







1 large downy 



Aug. 7, 1950 



weight 331 g. 



female 







