664 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



the nest was 144 minutes or 80 percent of the observation time. In 

 nests that I have had under observation in Maine, the male was seen 

 to deliver food to the female at frequent intervals and perhaps for 

 this reason these females left the nest less often. 



A. D. DuBois writes to me of an interesting reaction of a nesting 

 female to a mirror : "The spunky little female flew at a small mirror 

 which I held over the nest on the end of a stick ; she snapped her bill 

 and even grew bold enough to peck at it. On June 3 she again fought 

 the small mirror as I held it up to look into the nest, but she returned 

 to her eggs immediately when I withdrew the obnoxious looking- 

 glass," 



Young. — In one nest under observation at Brunswick, Maine, the 

 jfirst egg hatched while the adults were away from the nest. The 

 male was the first to return to greet the youngster and his first act 

 after an inspection of the nest was to remove the eggshells. The 

 male also delivered the first food, a small minced larva, when the 

 young was about 2 hours old. When the female returned, which was 

 shortly after the male's first visit, she carefully inspected the nest, 

 then immediately settled down to brood the young and the three 

 eggs. The male never brooded but he was very attentive in feeding 

 the young. If the female was at the nest when he arrived, the food 

 was presented to her and she in turn fed it to the young, but if she was 

 away the male fed the young directly. On the first day the youngster 

 was brooded 75 percent of the time. There were three young on the 

 following day, and the fourth egg proved to be sterile. The amount 

 of time required for brooding was more or less dependent on weather 

 conditions. On a cool, rainy day more time was spent on the nest 

 than when a moderate temperature prevailed. Wlien it rained the 

 female extended her wings over the edge of the nest and her head 

 was directed upward toward the oncoming rain drops. She thus 

 provided an effective roof to shield the helpless young from a disas- 

 trous soaking. The brooding instinct is very strong and if the young 

 were removed from the nest for purposes of study and photography, 

 the female mechanically brooded the empty nest the entire time the 

 young were out, seemingly unaware of their absence. In the after- 

 noon the nest was exposed to the direct rays of the sun and on hot days 

 the female perched on the edge of the nest with her wings half spread 

 and her back toward the sun. At such times she panted incessantly 

 in order to control her temperature through her intricate air-sac 

 system. It is just as necessary for the adult to protect the young 

 from heat as it is to keep them warm on cool days. The amount of 

 time spent in brooding becomes much reduced as the young grow 

 older, and by the time they have attained their covering of feathers 

 and acquire a temperature control there is little need for brooding. 



