July, 190S ANNOTATED I.LST OF THE BIRDS OF MESA COUNTY, COLORADO 



167 



Junction as early as March 4 and nests as early as the last week in April, with 

 young on the wing by June 1. In the higher parts of the County, however, the 

 dates of arrival and nesting are considerably later. My earliest arrival date is 

 March 21 and the earliest nest May 4, while the great bulk of the nests are two 

 weeks later. Raises two broods in a season and the bulk depart in September, 

 altho E. R. Warren has seen it at Grand Junction as late as October 4. 



Nuttallornis borealis. Olive-sided Flycatcher. Information is lacking regard- 

 ing the occurrence of this species within the confines of the County. It is in- 

 cluded in this list on the strength of a single specimen seen during the summer of 

 1905 at 6800 in Plateau Valley. I do not think it is common an3^where in the 

 County. 



Contopus richardsoni. Western Wood Pewee. Summer resident. Common. 

 One of the most common Fly- 

 catchers in the higher parts of 

 the County. Frequents the 

 quaking-aspen particularly 

 from 7000 to 10,000 feet where 

 its plaintive calls may be heard 

 continually during the breed- 

 ing season which is late in 

 June. The writer has not 

 seen it in any abundance below 

 7000 feet. 



[Kmpidonax difficilis. Wes- 

 tern Flycatcher. The al)sence of 

 this l)ird from the list can only be 

 accounted for by the lack of syste- 

 matic collecting by field workers, 

 as it is a common summer resident 

 thruoiit the mountains of the State 

 aud imdoubtedly occurs more or 

 less commonly in INIesa County.] 



Empidonax trailli. Traill 

 Flycatcher. Prof. Cooke says, 

 "One collected in June, 1893, 

 at Grand Junction by J. A. 

 lyoring. The species was not 

 rare and was breeding." 



[^Empidonax hammondi. 



Hammond Flycatcher. Whatever 



1 , -1 ,. ., .-.r NEST OF THE SAY PHOEBE; 



has been said regarilmg the Wes- 

 tern Flycatcher will apply equally well to this species.] 



Empidonax wrightii. Wright Flycatcher. Summer resident, common. Fre- 

 quents the open hillsides covered with "buck brush" from 7000 to 9000 feet, 

 where it nests commonly late in June. I have no information concerning its 

 migratory habits. 



Otocoris alpestris leucolaema. Desert Horned I^ark. Summer resident, not 

 common. Winter resident, abundant. Arrives in small scattered flocks with 

 the first cold weather and in large numbers with the first snow. It remains abund- 

 ant up to about April first when the birds begin to scatter and migrate and by the 

 middle of April is seldom seen. I am of the opinion that most of the birds winter- 

 ing here breed farther north and what few birds breed in the County come in from 

 the south. Miss Eggleston reports it as "abundant both summer and winter" at 



MESA. COUNTY 



