300 BULLETIN 19 7, UNITED STATES NATIONAL MUSEUM 



winter visitants. Early in January 1935 they sang much among the 

 shade trees of the Finca Moca, a great coffee plantation on the Pacific 

 slope at the base of the Volcan Atitlan. Their song resembled that of 

 the red-eyed vireo but was sweeter and more varied and was inter- 

 spersed with pleasing little warbles uttered in a low, soft voice. On 

 the morning of January 13 all the blue-headed vireos I met, four in 

 number, were singing persistently. Of course, a singing bird is far 

 more likely to attract attention than one which is silent. At noon I 

 came upon two that were singing against each other from neighboring 

 trees. One repeated all the notes of the other, as if in rivalry. They 

 continued this as long as I stopped to listen but did not lose their tem- 

 pers and clash, as so often happens under these circumstances. It is 

 rare to hear wintering birds sing in January and exceedingly rare to 

 hear them sing so much as these vireos sang. 



"In the highlands I often heard the blue-headed vireos sing during 

 April. When two came together they sang against each other like the 

 birds on the coffee plantation. Viree, one said; and other repeated 

 viree. Then the first called vireo; and vir^eo answered the second. 

 They continued this pretty conversation for some minutes." 



Many years ago, when my hearing was good, I wrote down my 

 impression of the song as hwee^^^, with a rising inflection as in the 

 redeye's song, or ^etOew, with a falling inflection ; sometimes there was 

 only the kew, or a short keiveek; again there was a rich and full koi/ 

 week, or per cheet. The first combination was the commonest, but it 

 was often varied by the second. 



The literature contains many references to the beautiful song of the 

 blue-headed vireo, but there is little that need be added to the above 

 accounts. William Brewster (1906) mentions an interesting bird that 

 "had two songs, one perfectly characteristic of his own species, the 

 other indistinguishable from that of the Yellow-throated Vireo. These 

 songs were invariably kept distinct, the notes of one never being inter- 

 polated among those of the other; nor was the bird ever known to 

 change from one to the other save after a well-marked interval of 

 total silence." Dr. Thomas S. Roberts (1932) writes: 



The sons is to be distinguished from the Red-eye's especially by two curious 

 characteristic phrases which are introduced at frequent inteiTals. These may 

 be recalled by tlie syllables wheop-tcu, the first note sharp and quick, the last 

 prolonged ; and the other couplet by the words johnny-cake, rapidly uttered. 

 Later in the season, mid-July, the song may consist almost entirely of these 

 notes and is then a curious medley of rvhcop-teu, whcop-teu, jolinny-cake, johnny- 

 cake, wheop-teu, and so on, with now and then a few sweet, vireonine notes. At 

 the end of the season, early in August, the whcop-teu call is all that remains and 

 this rings through the forest, an unmusical reminder of the beautiful song to 

 be heard no more until the coming of another nuptial awakening. 



Field marJcs. — It is only in the brightest light that the head of the 

 blue-headed vireo appears at all blue, and then it is only a bluish 



