FOOD HABITS OF THE SWALLOWS. 3 



tree swallow, for instance, eats a notable quantity of vegetable food, 

 and nearly all the species contrive to get a few caterpillars or other 

 wingless prey, and take at least a taste of Orthoptera (grasshoppers, 

 crickets, etc.). 



There are within the limits of the United States 13 species of 

 swallows, of which. the following seven are of such wide distribution 

 as to render their food habits a subject of economic interest : Purple 

 martin (Prognp subis) ; cliff, or eaves, swallow (Petrochelidon luni- 

 frons) ; barn swallow (Hirundo erythrog astro) ; tree, or white-bel- 

 lied, swallow {Iridoprocne bicolor) ; violet-green swallow (Tachy- 

 cineta thalassina) ; bank swallow {Riparia riparia) ; and rough- 

 winged swallow {Stelgidopteryx serripennis). The food of these 

 seven species is discussed in the following pages. 



PURPLE MARTIN. 



Progne subk. 



The purple martin (PL I, upper figure) occurs in nearly all parts 

 of the United States where suitable nesting sites are found. As its 

 nest is usually in a cranny of a building or in a house put up for its 

 express use, it follows that the bird breeds chiefly in settled portions 

 of the country. Probably at one time it nested in holes in cliffs, but 

 that time is long past, and now, showing the greatest confidence in its 

 human neighbors, the bird builds its nest as readily in the midst of a 

 noisy city as about a country cottage or on a quiet farm. 



For the determination of the food of the martin 205 stomachs were 

 available, collected throughout the United States with a few from 

 Canada. They represent the months from February to September, 

 inclusive, and are fairly well distributed through that period. Exam- 

 ination shows that the food consists entirely of animal matter, insects 

 with a few spiders and other allied creatures, with no trace of vege- 

 table food. The largest item consists of Hymenoptera (23 per cent) . 

 These were found in 129 stomachs, of which 7 contained no other 

 food. Ants (3.52 per cent) were found in 30 of these and formed the 

 sole contents of 2. As many ants have no wings, they are probably 

 snapped from the tops of weeds as the martin darts past. Occasion- 

 ally, however, the bird had evidently met a swarm of winged ants 

 and made nearly a full meal of them. Among the Hymenoptera were 

 some useful parasitic species. Ants, on the contrary, are annoying 

 if not harmful, so that while the bird's consumption of Hymenoptera 

 is on the whole not a decidedly good function, it certainly results in 

 little or no harm. Five stomachs contained remains of honey bees 

 (Apis meUifera) with an aggregate of 11 individuals, all of them 

 males, or drones. 



