CAROLINA DUCK 61 



Slave Lake region, May 15, 1885 (R. MacFarlane, 1908). At Ottawa they begin to 

 nest May 1st, and young have been found in June (J. and J. M. Macoun, 1909). In 

 Pennsylvania they nest in April or early May; in New England, April 23 to May 2, 

 though there are a number of much later dates, probably from females whose first 

 clutch had been disturbed. From late March through the whole of April is the usual 

 time in California, but late May dates are as elsewhere common. 



The average number of eggs in a clutch is probably eleven plus ; clutches vary from 

 nine to fourteen, but seldom number less than ten or more than thirteen. Unusually 

 large clutches have been frequently found: nineteen in a nest (Barrows, 1912); in 

 another twenty-one (Sampson, 1901), etc. Most of these large clutches are un- 

 doubtedly the work of two females, and Sampson, who examined his twenty-one 

 eggs very carefully, found nine of them to be somewhat darker and larger than the 

 rest. All late clutches are, I think, almost certain to be due to the destruction of the 

 first nest and not to an actual second brood as claimed by some observers, because 

 the female remains with the brood until they are well grown. The eggs themselves 

 vary in color from nearly white to a dirty yellowish buff or "old ivory" and are 

 rather globular in shape. The average dimensions are 2.05 by 1.58 inches (52 by 

 40 mm.), but eggs much larger and much smaller have been found (J. Dixon, 1924). 

 The period of incubation is longer than that of other surface-feeding ducks, Mal- 

 lard, Black Duck, etc., and varies from thirty to thirty-two days. Heinroth, who 

 puts the incubation period of the Mallard at twenty-six days, considers the Carolina 

 Duck as taking at least five days longer, which seems to me correct. From observa- 

 tions on confined as well as wild birds, it is found that the down is not usually added 

 to the nest until the clutch is nearly complete. It is gradually formed and becomes 

 dense during the first of the sitting. The down itself is white, as is the case with all 

 species which commonly nest in trees. Eggs are usually deposited in the morning, 

 which seems to be the case with most ducks, but Mr. Dixon (1924) records a case 

 where one of his wild females laid regularly in the late afternoon or evening. Ac- 

 cording to Heinroth the day on which the female lays the last egg may be taken as 

 the first day of sitting, and at this time the first eggs have reached a degree of incu- 

 bation equivalent to thirty-six hours of sitting. This discrepancy is completely cor- 

 rected because of the fact that the older eggs require a somewhat longer period for 

 development. But in the wild, Dixon found that incubation often began before the 

 set was complete. One of the birds he had under observation laid twelve eggs, but 

 she began to sit on the day the ninth one was deposited. Actual hatching was a slow 

 process, even taking as long as forty -eight hours in one case, which is not surprising, 

 for even with captive-laid eggs a set where all the eggs are started at one time will 

 take at least twenty-four hours to hatch out. 



While the females are sitting it is the general opinion that the males leave the 

 vicinity of the nest and collect in little groups. I have many times seen groups of 



