240 NYROCA FULIGULA 



structed and has a depth of about 14 centimeters. A very unusual nesting site for a 

 diving duck was recorded by P. D. Mallock (in Millais, 1913) on the high wall on 

 Castle Isle, Loch Leven, at 80 to 100 feet above the water. It seems that they do 

 not always walk to their nests! 



Eggs vary from six or seven to eleven or twelve but the usual number is from eight 

 to ten with the average around nine. Unusually large clutches, probably the result 

 of two or more birds, are mentioned. One nest in Ireland contained fourteen (Ussher 

 and Warren, 1900). Jourdain (in Millais) took nests that contained eleven, twelve, 

 fifteen, sixteen and eighteen eggs and one with sixteen was mentioned by Trevelyan 

 (1908). In fact he once saw in Derbyshire a female Tufted Duck sitting on top of a 

 pile of no less than twenty -eight eggs, which she was quite unable to cover, and he 

 believed that in this case about five ducks were laying in the same nest! 



The eggs are pale olive green, greenish buff, and pale yellowish or buff. They are 

 very similar to those of the Pochard, Scaup, Golden-eye and other ducks, but Mr. 

 Wormald assured me that in his ponds he could easily tell these eggs from those of 

 any other species of duck, which was more than he could say for most of his web- 

 footed friends. They are slightly smaller and lighter in color than the Pochard's or 

 Scaup's eggs. The average of 150 as given by Hartert (1920a) is 58.99 by 40.75 mm. 

 The maximum length was 65.9 and the minimum 53; the greatest width was 47.2 and 

 the smallest 37.7. The down is dark and compact with very obscure white centers 

 and without white tips, while the feathers scattered through it are grayish or whitish. 

 The down is said to be smaller and darker than that of the Pochard (Seebohm, 1885). 

 The total clutch is found to be three-quarters of the female's weight which is a large 

 proportion, apparently exceeded only by the White-headed Duck, Golden-eye, 

 Smew, Garganey, Mandarin, and Carolina Ducks (Heinroth, 1922). 



It is interesting to note that in a general way most of the diving ducks have larger 

 eggs than the surface-feeders as compared to the body weight of the female (Hein- 

 roth, 1922). 



The incubation period has been variously given as from twenty-three days to 

 twenty-eight days. I think that twenty-five days will be found nearer the average 

 time. Mr. Wormald's records showed this period, as well as Heinroth's (1908) cap- 

 tivity records. See also Trevelyan (1908); H. Noble (1908); W. Evans (1891). 



The eggs are laid early in the day and at first the male stays in close proximity, 

 acting as a sort of guardian and chasing away intruders. The female acts more or 

 less in the same fashion yet instances where two females make use of the same nest 

 are common enough. The young at first evidently secure a great deal of food off the 

 surface of the water; yet they can dive, although a little awkwardly, when only a few 

 hours old. The time submerged is at first short (five to eight seconds) but increases 

 with age. They can fly at about six weeks. The males, of course, leave the females 

 during the incubation and in late June leave the breeding quarters entirely. There 



