70 



BIRDS IN THEIR RELATIONS TO MAN. 



eaten only canker-worms and beetles, the former making 

 sixty-one per cent, of the food and the latter belonging 

 principally to a wood-boring beetle of the genus Psenocerus. 



Nearly half of the food 

 of several house- wrens 

 consisted of canker- 

 worms. 



Passing now to the 

 warblers (Mniotiltidce), 

 we come to many spe- 

 cies feeding largely on 

 canker-worms. Four- 

 fifths of the food of a 

 single Tennessee war- 

 bler consisted of these 

 insects. Two-thirds 

 of that of five sum- 

 mer yellow-birds was 

 canker- w orms, and 

 the same was true of 

 two chestnut -sided 

 warblers and also of 

 four black-poll war- 

 blers. A single black- 

 throated green war- 

 bler had eaten seventy per cent, of canker-worms, and two 

 Maryland yellow-throats had eaten forty per cent, of these 

 and forty per cent, of other caterpillars. Consequently canker- 

 worms composed nearly or quite two-thirds of the food of 

 these fifteen warblers. Seventy-nine per cent, of the food 

 of three warbling vireos consisted of caterpillars, more than 

 half of them being canker-worms. 



Out of a flock of about thirty cherry-birds, or cedar wax- 

 wings, seven birds were shot. With the exception of a few 

 Aphodii (small beetles) " eaten by three of the birds in 



THE BLUEBIRD. 



