96 



BIRDS OF A MARYLAND FARM. 



hoppers. Its good work among weeds has been previously described 

 (see p. 77). Eight stomachs were examined, but with little significance 

 of result, for the temporary abundance of May -flies had diverted the 

 birds from insect i)ests. 



One stomach of the rusty blackbird {Scolecoplmqvs carolimis) was 

 collected April 14, 1899. It contained beetles [llarpalus and Sitones), 

 1 caterpillar, 1 small bee, and some waste corn. The character and 

 extent of weed-seed destruction by rusty blackbirds on the farms at 

 Marshall Hall has been shown on p. 77. 



Crow blackbirds {Quiscalus quiscula) have been proved by examina- 

 tion of thousands of stomachs to take fully twice as much vegetable as 

 animal food, the vegetable food being chiefly grain and fruit. And at 

 Marshall Hall, after the young were established in life and the hosts of 



Northern birds, includ- 



ing the subspecies Quis- 

 calus (/aiscala seneus, had 

 arrived, sj'stematic pil- 

 lage of grain fields took 

 place (see p. 67), which 

 could be checked only by 

 the shotgun. Twenty- 

 five stomachs of the spe- 

 cies were examined. 



The orchard oriole 

 (Icterus spurius) is a sum- 

 mer resident at Marshall 

 Hall and may usually be 

 found nesting during the 

 breeding season to the 

 extent of a dozen paii's, though the present summer (1902) formed 

 an exception to this rule, the usual number being reduced to 2 or 3. 

 The food -of this species, as shown in 11 stomachs collected during 

 May and June, was composed of 91 percent animal matter and 9 per- 

 cent vegetable matter. The latter part was nearly all mulberries; 

 the former was distributed as follows: Fly larvae, 1 percent; parasitic 

 wasps, 2 percent; ants, 4 percent; bugs, 5 percent; caterpillars, 12 

 percent; gi-asshoppers, including a few crickets, 13 percent; beetles, 

 14 percent; May-flies, 27 percent; spiders, 13 percent. Thus bene- 

 ficial insects — parasitic wasps — formed only 2 percent of the food, and 

 injurious species — caterpillars, grasshoppers, and harmful beetles — 

 amounted to 38 percent. 



The Baltimore oriole {Icterus galbula) is also a highly insectivorous, 

 useful species, but occurs at Marshall Hall only during migration. 

 One bird was collected May 29, 1896. It had eaten mulberries, 2 

 small wasps, 2 fall webworms, 1 click-beetle, and 15 locust leaf -mining 

 beetles. 



Fig. 36. — Red-winged blackbird. 



