BAY-BREASTED WARBLER 383 



mouse gray," "deep brownish drab," "vinaceous drab," or "light pur- 

 plish drab." There is a wide variation in the manner of markings, 

 some being spotted with the reddish browns, others with shades of 

 "Brussels brown" or "snuff brown." Then too, eggs may have two or 

 three shades of brown mixed with the undertones of drab ; or they may 

 be marked only with tones of a single shade of brown and drab. Gen- 

 erally they are boldly spotted, sometimes with a few scrawls of black ; 

 while the coloring is concentrated at the large end, there is less tendency 

 to form a distinct wreath than in many other warbler eggs. The 

 measurements of 50 eggs average 17.7 by 12.9 millimeters; the eggs 

 showing the four extremes measure 19.0 by 13.4, 18.0 by 13.5, 16.4 by 

 13.3, and 17.5 by 12.3 millimeters (Harris). 



Young. — Howard L. Mendall (1937) gives the following summary 

 of his study of the home life of the bay-breasted warbler : 



The period of incubation was observed to be slightly over twelve days, and the 

 eggs hatched at intervals, with more than two days between the hatching of the 

 first and the fifth egg. Two young left the nest at eleven days of age. Incuba- 

 tion and brooding apparently are carried out solely by the female, which is, at 

 least part of the time, fed on the nest by the male. During the observation 

 periods from June 28 to July 3 (when there were five young in the nest), the 

 female averaged 26.4 feedings per hour, while the male fed on the average of 13 

 times an hour. However, under certain conditions and for short periods of time, 

 the male performed a much greater proportion of the nesting duties. Both adults 

 and one of the young were still together in the vicinity of the nest eight days 

 after the home had been forsaken. 



He observed that, during a heavy thundersliower, the female stood 

 over the young and sheltered them with her wings spread over the 

 sides of the nest; on a hot, sunny day she protected them from the 

 heat of the smi in a similar mamier. Two of the young were killed 

 by a red squirrel and the last one disappeared before leaving the nest. 

 Only the first two to leave the nest survived. 



Miss Stanwood's notes contain the following account of the activities 

 of the young a day or two before leaving the nest : "One little bird after 

 another pushed his way to the top of the bird heap, pecked at the oil 

 gland situated on the rump, wet his beak with oil, then dragged one 

 wing up slowly and oiled one feather at a time, pulling the feather 

 firmly through his beak from the root to the tip. Thus he made his 

 feathers waterproof and beautiful; thus, also, he removed those 

 annoying quill casings. After moistening his beak with oil the bird 

 rests; after preening a wing the bird rests again; then he moistens his 

 beak once more, rests, then preens the other wing and rests. The bird 

 may have been fed a number of times while this process is going on. 

 After feeding once more, and after the parent has again carried away 

 the excreta, he is thoroughly rested and his toilet is in perfect con- 

 dition. He is now ready to let another little warbler press to the top 

 of the nest in his place." 



