56 FOOD HABITS OF THE GROSBEAKS. 



Colorado potato beetle. Two stomachs of nestlings contained this lat- 

 ter nauseous ' insect, larvae being found in one, adults in another. 

 Wasps composed almost half of the food of one fledgling, and a 

 weevil and some small cocoons constituted the remaining animal 

 matter. 



Passing from these results of actual stomach examination to the 

 experiences of observers, • it should be noted that the rosebreast's 

 habit of feeding its nestlings the larvae of the potato beetle is fre- 

 quently recorded. This fa<;t is one of the best evidences of the 

 importance of this beetle in the grosbeak's regimen. Prof. F. E. L. 

 Beal " speaks of " a small potato field, which earlier in the season 

 was so badly infested * * * ^Yis^i the vines were completely rid- 

 dled. The grosbeaks visited the field every day, and finally brought 

 their fledged young. The young birds stdod in a row on the topmost 

 rail of the fence and were fed with the beetles which their parents 

 gathered." Prof. E. F. Hitchings, State entomologist of Maine, 

 gives the following interesting note: 



Several years ago I observed a pair nesting in a clump of trees jn * * * 

 Waterville. A piece of potatoes was planted near by, and I watched the parent 

 birds as they fed their young on the larvae of the Colorado potato beetle. I 

 examined the bills of the young and found them stained and even dripping with 

 the juice of the insects. It took a great many young larviB to satisfy them. 

 (May 19, 1906.) 



When we reflect that every year there are thousands of grosbeak ' 

 families throughout the breeding range of the species doing exactly 

 the same thing, it can not be doubted that they exert a marked effect 

 on the numbers of the potato beetle. 



The voracity of nestlings is proverbial, and their lusty appetites 

 greatly enhance theiif value as destroyers of injurious insects. The 

 number of insects eaten daily by nestlings has been recorded in the 

 case of but few birds; hence we are fortunate in having E. H. For- 

 bush's account of a study of the nestlings of the rosebreast : 



On June 12, 1899, Mr. Mosher watched the npst of a pair of rose-breasted gros- 

 beaks from early morning to 5 p. m. * * * For the first half hour the old 

 birds were so excited by his presence that tl^e feeding of the young birds was 

 interrupted, so that no notes were taken until 6 a. m., and none were taken after . 

 5 p. m. The old birds visited the nest — 



Times. 



Between 6 and 7 52 



Between 7 and 8 47 



Between 8 and 9 43 



Between 9 and 10 30 



Between 10 and 11 3G 



Between 11 and 12 : 27 



Times. 



Between 12 and 1 32 



Between 1 and 2 38 



Between 2 and 3 41 



Between 3 and 4 22 



Between 4 and 5 58 



making altogether 426 visits during the portion of the day that they were 

 watched. The food was mainly caterpillars of' one kind or another, and there 



« Farmers' Bull. 54, 1904, p. 35. 



