396 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



feet of the nest, on June 29, the day before the eggs hatched. Dur- 

 ing the 2 hours the female incubated the eggs for a total of 92 min- 

 utes, in five periods. The shortest time spent incubating was 11 min- 

 utes, and the longest 25 minutes, the average being 18.5 minutes. 

 I have noted that other incubating warblers often exhibit consider- 

 able restlessness toward the end of incubation and at this time leave 

 the nest more frequently and for longer periods of time. Presum- 

 ably the same may have been true of the blackpoll observed by Dr. 

 Sweet. 



When not on the nest the female could be heard flying about in the 

 nearby trees searching for food, but she made not the least sound 

 when approaching the nest. She invariably came to the nest from 

 a lower level and after reaching the base of the reclining spruce in 

 which it was located hopped up to the nest. Wliile incubating she 

 often dozed with her eyes shut, but upon hearing the least sound she 

 suddenly became alert. 



Eggs. — Complete sets of black-polled warbler eggs vary from three 

 to five, but four or five are more usual. The eggs have a white or 

 light creamy buff or sometimes a pale greenish ground color, with 

 brown and umber specks scattered over the whole surface and numer- 

 ous spots and blotches of reddish brown and subdued shades of lilac 

 and lavender concentrated at the larger end, sometimes forming a 

 wreath. 



The weights and measurements of a set of eggs found on Kent 

 Island, June 28, 1932, w^ere taken by Dr. Sweet as follows: 1.7 by 

 1.4 cm., 1.8 gm. ; 1.9 by 1.35 cm., 1.8 gm. ; 1.85 by 1.7 cm., 1.7 gm. ; 1.85 

 by 1.9 cm., 1.9 gm. The average of 77 eggs collected by J. P. Norris 

 (1890a) is .72 by .54 inch. Of this series the eggs showing the four 

 extremes measure .79 by .54, 73 by .55, .68 by .49, and .69 by .47 inch. 

 The average of 15 eggs collected by P. B. Philipp (1925) is .70 by .55 

 inch; the largest measures .74 by .56, and the smallest .66 by .54 inch. 

 A set of eggs collected by N. S. Goss (1891) on June 19, 1880, at Grand 

 Manan, New Brunswick, were unusually large, with the following 

 measurements : .77 by .55, .78 by .56, .78 by .56, and .79 by .56 inch. 



The measurements of 50 eggs average 17.9 by 13.4 millimeters, the 

 eggs showing the four extremes measure 21.8 by 13.7, 18.3 by 14.7, and 

 16.3 by 12.7 millimeters (Harris). 



Young. — The incubation period of the blackpoll is at least 11 days, 

 but the exact time was not determined because it was not possible 

 to ascertain the exact date when incubation started. Apparently it 

 may start before the set of eggs is completed, for in one instance 2 

 days elapsed between the hatching of the first and last of five eggs. 



After the young appear the adults exhibit even less fear of a human 

 observer. At Lost River, N. H., on June 30, 1932, 1 stood in full view, 



