Till' Regulative Action of Birds upon Insect Oscillations. 17 



PERDICID^E. Quails and Partridges. 



Ortyx yirginiana, L. Quail. 



Two quails were shot, among half a dozen seen. All but four 

 per cent, of their food consisted of corn and other seeds, chiefly 

 those of Composit£e. A single chrysomelid, a rhynchophorous 

 beetle, and a carabid, were the only insects found. 



Besides the species of birds above mentioned, the following 

 were noted rarely in the orchard, but no specimens were secured: 

 and Vbeo olivaceus., tSturnella tmu/na, Cyanurus cristatus., and 

 Chmtura pelasgica. The blue jay was seen eating canker-worms in 

 the trees. The total number of species observed in the orchard wa 

 therefore forty, and the number of specimens obtained and studied 

 was one hundred and forty-one, representing thirty-six of the 

 species. Twenty-six of these species had been eating canker- 

 worms, which were found in the stomachs of eighty-five speci- 

 mens. That is to say, seventy-two per cent, of the species, and 

 sixty per cent, of the specimens, had eaten the worms. Taking 

 the entire assemblage of one hundred and forty-one birds as one 

 group, we find that thirty-five per cent, of their food consisted of 

 canker-worms; and if we exclude the species evidently merely 

 accidental in the orchard, the average of canker-worms in the 

 food of those properly belonging there rises to about forty pe» 

 cent. 



For a correct estimate of the probable effect of the birds 

 in limiting the increase of the canker-worm, it is necessary to 

 take into account some of the features of its natural history. 

 The larval life of the insect lasts about one month, after which it 

 enters the ground and pupates, where it remains until the follow- 

 ing spring. The imagos, the females of which are wingless, 

 emerge about the mitldle of April. They lay their eggs upon 

 the bark of the trees, usually at night, remaining concealed upon 

 the ground by day under fallen leaves and other rubbish. The 

 eggs remain upon the trees about a month before the worms 

 emerge, when the latter crawl up the trunk and commence their 

 attacks upon the leaves. The pest is consequently exposed to 

 destruction from the time it emerges until it disappears again, the 

 adults falling an easy prey to birds which search the ground for 



