BIRDS OF BOULDER COUNTY, COLORADO 229 



The writer has observed the second nesting of the Robin on the plains 

 and did not notice any diminution in their numbers about Boulder. 

 On the other hand, he has observed Robins at 10,000 feet in the last 

 of April. While this negative evidence is not offered as proof that a 

 secondary migration for the purpose of nesting does not occur, it at 

 least indicates that more data are needed before such a claim can be 

 made for Boulder County birds. 



