Nest Life of the Catbird 173 



occurred at irregular intervals. The longest unbroken brood- 

 ing period lasted for one hour and twenty minutes. Simi- 

 larly on the twenty-fifth the nest was uncovered only nine- 

 teen minutes during the rain which lasted from 4:30 a. m. to 

 9 :40 A. M. The longest brooding period on this occasion 

 lasted three hours. Out of the total brooding time of 13 

 hours 4 minutes for this date, 5 hours 6 minutes were direct- 

 ly due to the rain. Leaving out of consideration these rainy 

 days, the brooding time seemed to be divided into three 

 more or less distinct periods. The first period from 4:30 

 A. M. to 7:30 A. M.; the second from 10:30 a. m. to 2:00 

 p. M.; and the third from 6 :30 p. m. until dark. The first 

 period was undoubtedly as a protection against the chill of 

 the early morning which often made sitting in the blind un- 

 comfortable work. During the second period the sun's rays 

 fell directly into the nest and the brooding at this time was 

 for protection against their heat. It was noticed that this 

 period never commenced until the rays were falling into the 

 nest and ceased as soon as the afternoon shadows were suf- 

 ficient to completely shade it. Unbroken brooding periods 

 for an hour or more were not uncommon at this time. The 

 brooding in the evening was possibly merely preliminary to 

 settling down on the nest for the night and was the most 

 variable of the three. It commenced to become dark in the 

 little ravine at about 6 :30 and by 7 :30 it was usually too 

 dark to distinguish objects from the blind. On the twenty- 

 ninth and thirtieth the noon period was very distinctly 

 marked and consumed the greater part of the brooding time. 

 On the twenty-ninth the early brooding totaled thirty-eight 

 minutes, the noon period three hours and ten minutes, and 

 the remainder was rather widely scattered thru the evening. 

 On the thirtieth only twenty minutes were spent in brooding 

 in the early morning, while four hours and fifty-four minutes 

 were consumed at noon, and twenty minutes in the evening. 

 The increase of the mid-day brooding on the thirtieth was 

 due to the intense heat, local thermometers registering 100 

 degrees F. or more. 



