52 FOOD OF THE FLYCATCHEES. 



YELLOW-BELLIED FLYCATCHER. 



(Empidonax jlaviventris.) 



The yellow-bellied flycatcher inhabits the northeastern United 

 States and Eastern British America in the breeding season, but in 

 migration occurs over most of the country east of the Rocky Moun- 

 tains. It is a lover of cool, shady forests and mountains and is 

 probably the most retiring and shy of the flycatchers. Its nest is 

 usually built in a damp mossy crevice of rocks or on the ground, or 

 among the upturned roots of a fallen tree, but always in a retired 

 place and is carefully concealed. Living apart from man and his works, 

 it does not come into contact with the farmer's crops nor his bees, 

 so its food, like the bird itself, is interesting chiefly to the bird student. 



For the study of this bird's food only 103 stomachs were available. 

 They were collected in 1 1 States, the District of Columbia, Ontario, 

 New Brunswick, and Nova Scotia. They were taken as far southwest 

 as Texas and as far northwest as Wisconsin. They are fairly well 

 distributed over the five months from May to September. The food 

 was found to consist of 97.01 per cent of animal matter to 2.99 of 

 vegetable, or practically of 97 to 3. Insects and spiders make up the 

 animal food and small fruit and seeds the vegetable. 



Animal food. — In the animal food, beetles amount to 16.53 per 

 cent. Of these the useful species aggregate 1.91 per cent and consist 

 of a few Carabidse and Coccinellidae. Most of the others are harmful, 

 while some are neutral. Beetles were found in 65 stomachs and were 

 eaten pretty regularly in every month. Diabrotica vittata, the striped 

 squash beetle, which is such a pest on squash, cucumber, and melon 

 vines, was found in S stomachs, and snout beetles, or weevils, were 

 noted in 25. All of these are more or less injurious. In 10 stomachs 

 were identified weevils of the genus Balaninus, which lay in nuts of 

 various kinds their eggs from which are hatched those fat white 

 grubs so common in chestnuts. 



Hymenoptera amount to 46.25 per cent of the food and were found 

 in 81 stomachs. Of these, 48 contained ants, which amounted to 

 13.42 per cent of the whole. Parasitic species were noted in 9 

 stomachs, and they made up 2.12 per cent of the contents. Hymen- 

 optera as a whole form the largest item of food in every month. 

 This bird is probably the greatest eater of ants of any of the flycatchers 

 and stands near the head in the eating of Hymenoptera in general. 



Hemiptera were found in 33 stomachs only, and amount to 4.16 per 

 cent of the food. Stinkbugs were found in 9 stomachs and assassin 

 bugs in 12, of which 10 contained a single species (Sinea diadema) 

 with as many as 6 in 1 stomach. The assassin bugs, like the stink- 

 bugs, prey upon other insects, and so are to a certain extent useful 



