180 



NATURE-STUDY REVIEW 



[11:4— Apr., 1915 



nest, but having:; a perfect view of it, while I was making notes and 

 taking a series of the least bittern. During the hours there on 

 several different days, I kept track of the tern's nest and found 

 that the two old birds took turns regularly, incubating the eggs. 

 The surprising thing was the shortness of the shifts. They changed 

 positions about every 15 minutes. This may not be normal. 

 This was the second set of eggs the last week in June and the birds 

 may have been restless. These eggs hatched the 13th day of 

 July. Study of another nest showed both birds sharing the work 

 of caring for the young. This nest hatched July 3d. The nest 



One on the nest while the other rested nearby. 



contained but two eggs. I found a floating egg about 15 feet away 

 and put it in the nest. Immediately, the birds made a great 

 outcry. Both were on the nest or by the nest almost all of the 

 time. The bird incubating would roll this foreign egg out of the 

 nest, then roll it back under its breast, but there was something 

 about the egg that was not right. It may have had the smell 

 of an enemy about it, or it may have been spoiled or more likely 

 the egg from another nest. Anyhow, the bird w^ould cover it for 

 a few seconds, then scream and thrust it out. Finally one of the 

 birds shoved its beak into the egg and flew away with it. These 



