980 U.S. NATIONAL MUSEUM BULLETIN 237 part 2 



The foregoing descriptions show little agreement, and not only 

 indicate how different the song sounds to different hsteners, but also 

 points to a considerable variation in the song itself. 



Joe T. Marshall, Jr., records in his field notes from the Aribabi 

 Hills, Sonora, the following song that may be atypical: 



"July 13 at the mesa camp this was the most conspicuous species, 

 with at least two males constantly smging, not only in the dawn 

 chorus, but all day at intervals. The song is terrifically loud. When 

 I first heard them at dawn, I thought they were A. carpalis near 

 camp. Later I found that they were loud-mouthed birds at least % 

 mile off or more — down in the gully bottom or far up on the next 

 rise. The song contains as a middle portion the entire trUl of 

 carpalis, which sounds actually like a field sparrow. It is preceded 

 by some shrill upward inflected sooeeps, and then some faltering 

 pliticks Hke an Empidonax julvifrons. Then, after the long trill, 

 there is another sooeep (or seeep). The singing all took place from 

 the top of oaks, usually on small dead twigs, where the bird is in 

 plain view but is so upright and motionless that the bird was actually 

 seen only three times." 



The song is invariably delivered from the top of a tree, bush, or 

 post — never from the ground — and is repeated at leisurely intervals. 

 Both Davis (MS.) and Francis Harper (1930) mention hearing the 

 song given by low-flying birds, but there is no instance of a true 

 flight song being delivered. In the United States the song seems to 

 be given from its arrival untU August. 



Field marks. — This sparrow is very difficult to identify in the field, 

 for it lacks distinctive plumage features. One seeing it for the first 

 time can easily confuse it with other sparrows, particularly Cassin's, 

 and possibly the rufous-crowned or even the shorter-tailed grass- 

 hopper and Henslow's sparrows. It generally does not associate 

 with any of these but Cassin's, with which it often shares its nesting 

 range. When in song the males can be separated readily. Other- 

 wise the two species can be distinguished only with difficulty, even 

 in the hand. 



Seasonal occurrence. — In Texas, Botteri's sparrows begin to arrive, 

 presumably, in late April and most if not all the breeding birds are 

 on hand by May 15. By the end of September, presumably, most 

 are gone again. Authentic records are almost lacking. In Arizona 

 the birds do not appear until the latter part of May, and depart by 

 September (extreme dates May 17 and October 7). Virtually nothing 

 is known of its breeding occurrence in Mexico. Two August speci- 

 mens in full Juvenal plumage were taken in Michoacan and Guerrero, 

 and a July specimen in the same plumage came from Oaxaca. 



