156 BiCKNELi. on Hylocichla alicice bicknelli. 



But to return to the mountain. It would hardly be justifiable 

 to make a positive statement about a difficult song that had been 

 but once identified, but I feel positive that the Thrushes which 

 were last heard that evening about our camp on the extreme 

 summit of the mountain were of the new form. Night was 

 rapidly falling, and the valleys were in darkness, when one sang 

 several times near the camp, and for some time afterwards a sin- 

 gle call-note was occasionally heard, and the varying distance of 

 the sound showed that the birds were still active. Excepting 

 these sounds, the last bird notes heard were those of the Yellow- 

 bellied Flvcatcher. 



The sharp northwest wind continued late, and the night be- 

 came clear and cold. Shortly after midnight the bright moon 

 showed the temperature, by a thermometer which I had hung 

 beside the camp, to be 35°, and at sunrise it stood at 32°. Before 

 daylight I was standing on a boulder of conglomerate on the dmi 

 mountain's brow Ustening for the awakening, of the birds. The 

 first songs heard were those of the Hermit Thrush, Snowbird, 

 and Yellow-bellied Flycatcher, which began almost simultane- 

 ously, followed a little later by those of the Olive-backed Thrush 

 and " the Mourning Warbler, but H. bicknelli was not heard, 

 or afleast not near enough to be distinguished among the other 

 species. 



The increasing light upon the mountain seemed to attract the 

 birds from below, whither, perhaps, they had retired for the 

 night, and soon many different notes were to be heard about 

 the camp ; not, however, in that boisterous chorus with which 

 the day is often announced about our homes, in which the notes of 

 many individuals of many species are blended in such confused 

 medley that separate voices are almost indistinguishable, but 

 simply the association of a few vocalists, the very isolation ot 

 whose position endowed their voices with an additional interest 

 and charm. 



After those already mentioned the Black-poll Warbler { Den- 

 drceca striata) began its unpretending notes, which always to 

 me suggest a short dotted line, and this song, with that of the 

 Black-lmd-Yellow Warbler, occasionally alternated about us m 

 agreeable contrast. Now and then a Canada Nuthatch, on its 

 mornin- tour, tarried to inspect some dead trunk or thinly clothed 

 tree up^on the projecting apex of which, or that of some com- 



BiCKNEi.L on Hylocichla alicice bicknelli. 



panion. a solitary Purple Finch occasionally alighted, and with a 

 few wild fugitive notes was gone, to other mountain tops or the 

 forests of the descending slopes. 



But to revert to the Thrushes. The two specimens of the new ' 

 form which were obtained were both males, and were unques- 

 tionably breeding,* though no nest known to belong to their 

 species was found. 



It remains to briefly consider some facts furnished by the birds' 

 occurrcuce as narrated. These facts bear directly on the long 

 contested question of the relationship which H. alicice and H. 

 swainsoni bear to one another, and it can scarcely be denied 

 that the present evidence on this point is conclusive. Not only 

 ha\ e we representatives of both birds preserving their respective 

 identities at the same locality, under identical conditions of en- 

 vironment, but examples of each taken under these circumstan- 

 ces, display, except in size, even a greater dissimilitude than 

 those which occur together on their migrations. There is but 

 one tena1)le interpretation of these facts: the birds — Hylocichla 

 alicice and H. ustulata szvainsoni — are wholly and entirely dis- 

 tinct. Any theory of dichromatism which might be advanced, 

 'aside from its extreme unlikelihood, would be shown inadequate 

 by the relative ditferences in proportions of parts which the two 

 birds exhibit. These differences, as well as those of color are 

 illustrated by the Catskill birds. A specimen of H. swainsoni 

 taken at the top of Slide Mountain was in every way typical of 

 its species, and conspicuously unlike the examples of bicknelli 

 taken at the same time. Aside from differences in the propor- 

 tions of parts, the two birds were strikingly different in color, the 

 decided grayish olive tinge of the superior surface of sxvainsoni 

 contrasting strongly with the much darker brownish cast of its 

 cono-ener. One example of the latter instead of showing indica- 

 tions of a buffy tinge about the sides of the head and on the breast, 

 which under the circumstances we should expect to be the case, 

 were it in any way specifically related to swainsoni, has ab- 

 solutely no indications whatever of this shade about the sides 

 of the head, and actually less on the breast than any speci- 



* Both birds were carefully examined and the evidence on this point was positive and 

 unequivocal. A Thrush's nest containing spotted eggs discovered near the top of Slide 

 Mountain may have iDeen either that of this form or of swainsoni, but as positive iden- 

 tification was prevented, further allusion to it is, for the present, withheld. 



