ON TREES AND BIRDS. 155 



with the beetles which their parents gathered. When 

 a careful inspection was made a few days later, not a 

 beetle, old or young, could be found ; the birds had 

 swept them from the field and saved the potatoes. 



THE BLACK=HEADED GROSBEAK. 



The black-headed grosbeak is found over the whole 

 Pacific coast and Rocky Mountain region, and takes the 

 place filled by the rose-breasted grosbeak in the eastern 

 part of the United States. In its general habits, in- 

 cluding its food, it much resembles its eastern relative, 

 though it lacks the latter's brilliant ornamentation on 

 the breast and under the wings. Seventy stomachs of 

 this bird have been examined, showing 74 per cent of 

 animal and 26 of vegetable food. Caterpillars consti- 

 tute over 18 per cent of the food, a surprisingly large 

 amount for such a stout-billed bird, which seems better 

 adapted for eating nuts than such soft creatures as 

 caterpillars. One interesting point may be noted in 

 this connection. Thirty-five of the stomachs were 

 from birds taken in an orchard infested with the cod- 

 ling moth. It was a question whether the grosbeaks 

 preyed upon this pest in any of its forms. No moths or 

 larvae were detected, but pupae were found and fully 

 identified in 12 of the stomachs and amounted to 8 per 

 cent of the food of the 35 birds. It is unfortunate that 

 the codling moth in the adult form flies by night and in 

 the larval form burrows at once into the apple, so that 

 it is protected from birds in both these stages. 



