﻿VENEZUELAN ORNITHOLOGY — FRIEDMANN AND SMITH 503 

 MACHETORNIS RIXOSA FLAVIGULARIS Todd 



Machetornia rixosa flavigularis Todd, Ann. Carnegie Mus., vol. 8, 1912, p. 210 

 (Tocuyo, state of Lara, Venezuela). 



SPECIMEN COLLECTED 



IcT, Cantaura, April 7, 1946; gonads very much enlarged; iris red-brown; 

 feathering very abraded. 



This interesting flycatcher was found in bushy fields, generally not 

 far from water. It was often seen following cattle, running along 

 beside their feet or perched on the animals' backs. The bird was not 

 common in the area but was observed at Cantaura from late in 

 January through June, August through October, and in December. 



The bird utters mouselike, squeaky, and twittering notes and also 

 a sharp, hissing seep. 



MUSCIVORA TYRANNUS TYRANNUS (Linnaeus) 



Muscicapa tyrannus Linnaeus, Systema naturae, ed. 12, vol. 1, 1766, p. 325 

 (Surinam). 



specimens COLLECTED 



Icf, 19, Cantaura, July 24 and September 19, 1948; gonads small; iris brown, 

 feet black, bill black; gizzards contained insects; male not fat. 



The female, taken July 24, is a young bird molting into adult 

 plumage, part of the feathering being partly frayed, brownish, juvenal 

 plumage and partly fresh, adult plumage. The top of the head is 

 pale brownish gray bordered frontally, laterally, and posteriorly with 

 black, with one black and one yellow feather coming in on the fore- 

 crown. 



The male, taken September 19, shows active molt in the wings and 

 tail; the two outermost primaries are barely sprouted but fortunately 

 show enough of their distal parts to enable definite subspecific identi- 

 fication to be made. The young female is identified to the same race 

 only inferentially and by its dark upperparts. 



There was very great seasonal fluctuation in numbers. During two 

 successive years the collector observed the formation of a concentra- 

 tion at a favorite spot about 10 miles north of Cantaura. Up to the 

 second week of July less than 10 bu"ds were recorded in a day. From 

 then on the number remained at slightly less than 50 birds until late 

 in August, when there was a sharp increase. From this time until the 

 thu'd week in September there were not less than 3,000 birds in the 

 concentration, by careful repeated estimates, and at times there 

 appeared to be double this number present. By the second week in 

 October no more than 200 or 300 birds remained. Although the 

 fork-tailed flycatcher was recorded throughout the area, the collector 

 knew of only two such concentrations within the study area. The 

 birds composing the July and August flocks were generally short- 



