WRENS. 



61 



Among the 36 stomachs, of which the record has just been given, 

 were 18 nestlings, some being about a week old, others about ready 

 to leave the nest. The results of the examination of these were tabu- 

 lated by themselves in order to determine the differences, if any, 

 betAveen the food of the adults and that of the young. No vegetable 

 matter was found in any of the stomachs, and the animal food was 

 distributed among a comparatively few elements. Bugs (Hemiptera) 

 are the largest item, and amount to nearly 36 percent. Caterpillars 

 and grasshoppers stand next, with 17 and 16 percent, respectively. 



It is interesting to note that about three times as many grasshop- 

 pers are fed to the young as are eaten by the adults. Wasps and ants 

 amount to a little more than 6 percent, and are the smallest item. 

 Spiders appear to the extent of a little over 11 percent. Beetles, 

 however, constitute the most interesting item of the food. They 

 were eaten to an average extent of somewdiat more than 11 percent, 

 and were nearly all hidybirds (Coccinellida^) contained in the stom- 

 achs of five individuals of a brood of six. The amount in each 

 stomach varied from 15 to 65 percent of the contents, and averaged 

 29 percent of each of the six birds. It is a question which is the more 

 surprising, that this brood had eaten so many coccinellids, or that 

 the others had eaten so few^ Only three other stomachs contained 

 any of these beetles and those were all adults. The house wren does 

 not exhibit any special proclivities for ladybirds, and it would seem 

 probable that in this case either other food was wanting or these 

 beetles were specially abundant. 



In addition to the examination of stomachs, observations were made 

 upon the feeding of nestling wrens. A nest situated in the porch of 

 the house of Mr. W. O. Emerson, at Haywards, Cal., was observed 

 for one-hour periods from soon after the young were hatched until 

 they were nearly ready to fly. The nest was watched at various times 

 of day, so as to include as nearly as possible all hours of daylight. 

 During the first two periods the male aided in feeding the young, 

 hut afterwards w^as not seen, and the whole care of the young de- 

 volved upon the mother. The number of young probably was not 

 fevrer than six. FoUovvinir are the results in tabular form: 



