SOME PROBLEMS WITH EVERYDAY BIRDS 



721 



scene of devastation, but were happily disappointed. 

 Here, too, the eggs had hatched, but the young were still 

 unharmed. In fact, while we were still there, the male 

 came from our nest and began singing in the nearby tree 

 with all his previous exuberance. Nor did he disturb this 

 nest at all, but helped to feed the young until in due time 

 they left the nest. 



But what became of our female? Four days passed 

 before she reappeared and when she did do so, it was 

 with a feather in her bill, and she set to work to rebuild 

 the nest that the male had ruined. The male had con- 

 tinued to sing in the vicinity as though nothing had hap- 

 pened and when she reappeared he mated with her as 

 before. Six more eggs were laid and these did not hatch 

 until the young had left the other nest. This was appar- 

 ently more satisfactory to the male for, although up to 

 this time he had been assisting the other female to feed 

 her young, he now became very attentive to our young 

 and assisted them through to maturity. In the meantime, 

 the other female got her young started in life, came back, 



ALSO OF THE SPARROW FAMILY 



The chipping sparrow has departed somewhat from the type color pattern, 

 having lost the streaks that once marked its underparts. 



renovated her nest and with the help of the male started 

 another brood. Thus the male fathered four broods, one 

 of which he did away with, apparently because he could 

 not care for two broods at the same time. 



How general polygamy is among wrens has not yet 

 been recorded, for it takes unusual conditions to deter- 

 mine it accurately. But the fact that they are so at all 

 suggests a good explanation for the duplicate nests. 

 These duplicate nests are built entirely or nearly so by 

 the male birds and very probably to attract the females 

 as a sort of a mating performance. The fact that the 

 males continue to build after having secured one mate, 

 and the fact that the habit is so prevalent throughout 

 the family suggest that polygamy was one of the fixed 

 habits of the wren progenitors and that duplicate nest 



building and occasional polygamy are the vestiges of this 

 ancient habit. 



Another interesting problem that concerns the hortie 

 life of birds is that of the gregarious nesters like the night 

 herons and the bank swallows. Why this habit should 

 have developed with certain species and not with others 

 will always invite thought and theory. That the presence 

 of others of the same species nesting in the near vicinity 

 is irritating to most birds is a familiar fact. Usually one 

 pair, when nesting, will not permit the close approach of 

 any other bird, especially one of the same species. Social 

 nesters, like the bank swallows, are the exception. 



The rough-winged swallows are particularly solitary 



THE EVENING GROSBEAK 



This bird is an unusual member of the sparrow family. He is marked differently 

 from the typical sparrows, being bright yellow, black and white. 



in their nesting habits as compared with the bank swal- 

 lows. They nest in old kingfisher burrows, drain pipes 

 or crevices in the cliffs and though two or three pairs 

 may build in the same vicinity, they are never truly 

 gregarious or social and resent the approach of other indi- 

 viduals near their nests. While working with a pair that 

 were nesting in an old kingfisher burrow, I noticed two 

 other swallows which were nesting at a considerable dis- 

 tance occasionally flying past or even hovering for a 

 minute before the entrance to my birds' burrow. Usually 

 they were promptly set upon and driven away. Gradually 

 I became aware, however, that both birds of the other 

 pair were not being treated alike. One was always, with- 

 out exception, attacked by both my birds and driven away, 

 while the other passed to and fro without molestation. 

 When I removed the young from the nest and perched 

 them on a wire fence to photograph them, the second pair 

 of swallows appeared and, as usual, one of them was 

 promptly driven away but the other was allowed to 

 remain. In fact, this swallow caught a passing damsel 

 fly and actually fed it to one of the young as though it 



