WRENS. 



59 



Other beetles, mostly leaf -beetles (Chrysomelidpe) were eaten to 

 the extent of a little more than S j)ercent. While nearly all of the 

 leaf-beetles are theoretically liariiifiil none of those identified in the 

 food are especially destructive to (;rops. 



IIymeno[)tera, inchidin<>- both ants and wasps, aggreg'ate a little 

 more than IT percent of the wren's diet. They are a fairly constant 

 constituent of the food and do not appear to vary much according to 

 season. The greater number was found in March, but as only two 

 stomachs Avere collected in this month the record is not conclusive. 

 Ants foi'ni about T percent of the food. The economic relations of 

 these insects have been discussed elsewhere. Wasps make up the rest 

 of the item, about 10 ]jercent, and have no especial economic signifi- 

 cance. Caterpillars and a few moths and some cocoons constitute a 

 little less than 12 percent of the wren's food. Contrary to what 

 might be expected, not all these are taken in summer. The 1-f 

 stomachs obtained in February contained caterpillars to the amount 

 of. ov^er 13 percent of their contents. They were probably found 

 hibernating in crevices of bark, A few moths were eaten, but, as 

 usual, they were only a small item of the food. Small cocoons of 

 tineid moths wei'e found in a number of stomachs. 



Grasshoppers amount to 4 percent of the wren's diet. Most of 

 them are eaten during the summer and fall, though some appeared in 

 stomachs taken in January, While these insects are a favorite food 

 for many birds they are probably rather large and too terrestrial in 

 habits to be eaten in great numbers by wrens. Other insects, mostly 

 flies and a few remains Avhich could not be identified, make up about 

 G percent of the stomachs' contents. Flies (Diptera) are eaten very 

 irregularly and appear not to be relished. Spiders are taken to the 

 extent of somewhat more than 5 percent of the total food. As spiders 

 live about trees, bushes, fences, rocks, and outbuildings it is not sur- 

 prising that they are captured by wrens, but the rule seems to be that 

 while all insectivorous birds eat spiders to some extent no species eats 

 many. 



List of insects found in stomachs of Bewick wren : 



COLEOPTERA. 



Ccrcyon fulvipenne. 

 II ipiKxlu III la con vergens. 

 ('Dciiirlhi t. californiro. 

 Scj/iii II us 111 ari/iii icoJIis. 



\llll'l(lills IIKl'lfroilH. 



M irrorhoimlii monlnua. 

 Diachiis aiirutuN. 

 CiriiiilfKlrra lirl.rines. 

 Uliilli.r lliimilil. 

 llrciiKi coiiNiicrxd. 



Diabrotica soror. 

 Cryptoccpliahis ciistniiriis. 

 GdsiroUlca sj). 

 Bniclnis sciiiiiiinniii. 

 BUipstUi 11 fi (lilatatiiK. 

 A'o/oj-H.s aJameda'. 

 Cr II torh yn cli ii s nod ipcn n is. 

 /'clrnoiii IIS c(i rifroiis. 

 Apion sp. 



