CONTINENTAL RUSTY BLACKBIRD 289 



Caterpillars constitute 2.5 percent and do not form any very striking percent- 

 age at any time, except, perhaps, in May, when they amount to 11.7 percent. 

 Grasshoppers nearly equal beetles in the extent to which they are eaten, and 

 exceed every other order of insects, although none appeared in the stomachs 

 taken in January, March, May, and December, and in February but a trace. 

 In August, as usual, they reach the maximum, 44.3 percent, only a trifle higher, 

 however, than the October record. The average for the year is 12 percent. 

 Various orders of insects, such as ants, a few bugs, and also a few flies, with such 

 aquatic species as dragon-flies, caddice-flies, and ephemerids were eaten in all the 

 months except January, in which only one stomach was taken. They aggregate 

 13.7 percent of the whole food, but owing to the number of forms no one amounts 

 to a noteworthy percentage, and many of them are of little economic importance. 

 Spiders and myriapods (thousand-legs) are eaten to the extent of 4 percent and 

 amount to 23 percent in August. Other small animals, such as crustaceans, 

 snails, salamanders, and small fish, were found in the stomachs for nearly every 

 month, and amount to 7 percent of the food of the year, but none of them are 

 important from an economic point of view. 



The vegetable food consists of grain, 24.4 percent, weed seed, 6 

 percent, and miscellaneous substances such as a small amount of 

 fruit and a little mast, 16.6 percent of the food of the year. Of grain, 

 corn seems to be the favorite, amounting to 17.6 percent of the year's 

 food and averaging as much as 26.5 percent in 15 stomachs collected 

 in November. "Wheat and oats collectively amount to only 6.8 

 percent of the year's food. Oats are apparently preferred and in 

 March constitute 15.4 percent of the month's food. These March 

 stomachs came from the Southern States, so it is probable that the 

 grain was picked up on newly sown fields." Weed seed is not an 

 important item, amounting to only 6 percent for the year; its "erratic 

 distribution evidently indicates that weed seed is not sought after, 

 but is simply taken when nothing better is at hand. Miscellaneous 

 items of vegetable food amount to 16.6 percent of the food of the year. 

 Fruit was found in a few stomachs, but does not appear to any im- 

 portant extent. Only three kinds were determined, but several 

 stomachs contained pulp or skin that could not be identified. Several 

 buffalo berries (Shepherdia argentea) were found in one stomach, 

 hackberries (Celtis occidentalis) in another, and seeds of blackberries 

 or raspberries (Rubus) in two or three others. Mast was found in 

 a few stomachs, but the greater part of the miscellaneous food was 

 indeterminable." 



Francis H. Allen tells me that the rusty blackbird feeds on the 

 seeds of the white ash. Milton P. Skinner (1928) says that, in North 

 Carolina, "in addition to the seeds, waste grain and insects usually 

 eaten by all blackbirds, the Rusty Blackbirds add fruits from the 

 sour gum in December, January and February, and dogwood berries 

 in January. In February, Rusty Blackbirds feed in cowpea fields on 

 insects, but do not disturb any waste peas that may be present." 



