672 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



It has been suggested by critics that these reports were based on 

 seeing the first-year male, which has a pkimage similar to that of 

 the female and could be easily mistaken for a female. The male 

 breeds the first year in this plumage and this adds to the confusion. 

 However, it has been definitely proved that the females do sing at 

 times. J. L. Baillie, Jr. (1926) collected a female at Lowbush, Lake 

 Abitibi, Ontario, on June 3, 1925, which was singing one of the usual 

 songs of the male, including the usual swee-a^ swee-a notes. The 

 specimen was carefully sexed and was found to have enlarged ovaries ; 

 hence, no mistake was possible. On June 22, F. W. Braund (Braund 

 and McCullah, 1940) heard what appeared to be a singing male on Anti- 

 costi island. Wlien seen it was thought to be a young male in im- 

 mature plumage in full song, but after it was collected and sexed it 

 proved to be an adult female. These and other similar cases indicate 

 that some females sing the full song of the males, although it is 

 unusual for them to do so. 



Albert R. Brand (1938) has determined the vibration frequencies 

 of the songs of many passerine birds from motion-picture film re- 

 cordings. The highest note in the song of the redstart had a fre- 

 quency of 7,300 vibrations per second, the lowest 4,400, and the 

 approximate mean of 6,200 vibrations per second. It is of interest 

 to compare the mean of the redstart with that of the blackpoll warbler, 

 which has a mean of 8,900, whereas the mean of the yellow-breasted 

 chat is only 2,600 vibrations per second. 



Horace W. Wright (1912) has observed the early morning awaken- 

 ing of birds at Jefferson Highlands in the Wliite Mountains of New 

 Hampshire. Of the redstart he writes : "If the Ovenbird is excepted, 

 the Redstart introduces the warbler singing. All warbler song is 

 delayed on the average until 3.29, when the Ovenbird begins to 

 sing. The Redstart based on ten records, averages to sing seven- 

 teen minutes later, or at 3.46 o'clock. It has been heard once as 

 early as 3.26, but on three other occasions was first heard at 3.55. 

 3.56, and 3.58 respectively. Two and sometimes three birds sing 

 within hearing. On June 28, 1911, the first bird began to sing at 3.41, 

 the second was heard at 3.49, the third at 3.52, and the three con- 

 tinued singing much of the time up to 5.15 o'clock." He states further 

 that the Redstart was one of only three warblers which were heard to 

 sing after sunset, which at the time the records were taken was at 7.30 

 p. m. 



Enemies. — The redstart's habit of nesting in rather tall slender 

 trees, usually at a considerable distance from the ground, frees it from 

 most of the enemies to which ground-nesting birds are subject. 

 However, I know of one nest of the redstart, built in a shrub about 

 4 feet above the ground, that was destroyed by a cat, and of another. 



