The Regulative Action of Birds upon Insect Oscillations. 7 



The catbird bad shown its visual preference for ants, eating four- 

 teen per cent, of these insects. These birds had taken an unusual 

 numlier of Coleoptera, which made more than half the food, 

 chiefly Scarabreida?. About two-thirds of them belonged to the 

 single species {Anomala binotata) mentioned above under the 

 food of the robin. Three of these birds had likewise eaten large 

 June bugs. Elateridse and their larvse occurred only in trivial 

 quantities, while Carabidfe amounted to four per cent., chiefly 

 Anisodactylus. As in the robin, Diptera, Orthoptera, and Arach- 

 nida, were not represented in the food. 



Harporhyxchus rufus, L. Brown Thrush. 



This bird was not common in the orchard, and only four speci- 

 mens were taken. The food of these was entirely animal, an 

 unexpected circumstance, as the brown thrush usually feeds 

 largely upon grain. Six per cent, of the food consisted of 

 thousand-legs, and insects made the entire remainder. Lepidop- 

 tera were about one-fifth of the food, and half of these were 

 canker-worms. Like the precedmg species, this bird had eaten 

 an enormous number of beetles, which amounted to two-thirds of 

 its food. Twelve per cent, of the whole was Carabidae, chiefly a 

 species of Chlasnius. Scarabgeida^ stand at forty-four per cent., 

 largely Diplotaxis, Melolontha, and Anomala. Six per cent, were 

 Elaterida^, and three per cent. Rhynchophora. No specimens of 

 the remaining orders had been eaten by these birds. 



S u in ia a r y of the Family. 



Treating, now, of the twenty-seven thrushes mentioned as one 

 group, we find that none of them had eaten any vegetation what- 

 ever; that ninety -six per cent, of their food consisted of insects 

 (myriapods and earth-worms making up the remaining four per 

 cent.); that sixteen per cent, was canker-worms; and only four 

 per cent, predaceous beetles. The Anomala previously men- 

 tioned made just a fourth of their entire food, other Scarabfeidae 

 bringing up the average of that family to thirty-eight per cent. 

 Click beetles (Elateridte) with their larva' were five per cent, of 

 the whole, and snout beetles (Rhynchophora) two per cent. 



