Period 
of 
incubation 
15 days 
Male 
Red-eyed 
feeds his 
sitting 
mate 
so often noticed in sitting birds. Gilbert tells me that he 
looked at the nest about ten minutes after I had left it and 
that the Vireo's head was then in sight, although she was 
resting her bill on the side of the nest. 
As I have already noted, this nest contained one 
egg at 7 A. M. on June 2nd (it was empty at 7 P. M. on the 
1st) and four on June 5th (at 9 A. M»). Assuming that the 
bird began incubating on the morning of the 5th (she was 
then on the nest and apparently sitting steadily) it has 
taken her thirteen (13) days to hatch three of her eggs. 
In the garden at Cambridge to-day (at IP. M.) I 
saw a male Red-eye feed his sitting mate. He approached 
the nest by a succession of short flights, singing steadily 
the while, although he held in the tip of his bill the 
morsel of food which his mate took from him without leaving 
her eggs. It looked like a small beetle. 
