308 U. S. NATIONAL MUSEUM BULLETIN 211 



struction and copulation was being performed. As in second cycles, 

 Phase 1 may be extremely short, a matter of only a few days, or may 

 be passed over entirely. 



At about the same time that the secondary female starts to incu- 

 bate, the primary's eggs have usually hatched and the male assists in 

 feeding the nestlings. The periods that the young are in the two 

 nests of a polygynous male may overlap and the male generally feeds 

 at both nests. This attention by the male to nestlings at two nests 

 has been observed on the same day. Where simultaneous observa- 

 tion of both nests was possible, the male was sometimes seen to make 

 feeding trips to each nest, dividing his time irregularly between the 

 two. Likewise, attention to nestlings in one nest and fledglings from 

 the other has occurred on the same day. 



In the exceptional year, 1947, when the ratio of males to females 

 was one to two, polygyny was at its height. There were certain cases 

 of polygyny in which it was difficult to determine whether the usual 

 attention was paid to the secondary female. There were also certain 

 cases in which a polygynous male acquired mates almost simultane- 

 ously, and the timing of the cycles of these females were more or less 

 parallel. 



Males were observed in 1947 feeding nestlings at more than the 

 usual two nests; one fed at the nests of his three females; another 

 brought food to the nests of his four mates. However, since never 

 more than two nestling periods of any one polygynous male were 

 known to overlap, two was the maximum number of nestling broods 

 fed on the same day. 



Concurrently with this state of polygyny there was a remarkable 

 faithfulness in the remating of primary pairs. Of the 45 cases in 

 which both members of a primary pair were present the following 

 year, 42 remated and only 3 were "divorced." In addition, among 

 the returns there were six birds that had been mated to unbanded birds 

 the previous year. Some of these unbanded birds may, of course, 

 have returned the following year and might have added to the total 

 of either faithful pairs or divorces. In some cases primary pairs 

 remated for a number of consecutive seasons. Of the total of 70 

 primary pairs, 44 were maintained for 1 year, 15 for 2 years, 7 for 3 

 years, 3 for 4 years, and 1 for 5 years. No male had the same female 

 in secondary status more than once. 



A monogamous male's mate and the first seasonal mate of a polyg- 

 ynous male are considered primary females; the mate, or mates, of a 

 polygynous male which are subsequently acquired in the same season 

 are considered secondary females. (In a few cases in the exceptional 

 year 1947, designations as to primary and secondary status were made 

 with possibly some arbitrariness.) Thirty-four banded females were 



