THE YELLOW-HEADED BLACKBIRD. 31 



data regarding the food. As indicated by the contents of these 

 stomachs, the food for the seven months consists of 33.7 percent of 

 animal (insect) matter and 66.3 percent of vegetable matter. The 

 animal food is composed chiefly of beetles, caterpillars, and grass- 

 hoppers, with a few of other orders, while the vegetable food is made 

 up almost entirely of grain and seeds of useless plants. Predaceous 

 beetles (Carabidfe) constitute 2.8 percent of the season's food, a very 

 small amount for a bird of such pronounced terrestrial habits. Most 

 of these beetles are eaten in May, June, and July, and none are taken 

 in the fall months. Other beetles amount to a little more than 5 per- 

 cent, and are eaten mostly in the early part of summer. Caterpillars 

 constitute 4.6 percent, but nearly two-thirds of them are taken in 

 July, and in that month they form 21.5 percent of the month's food. 

 Remains of the army worm {Leucania unipuncta) were identified in 6 

 stomachs. Grasshoppers are first eaten in May, but do not amount to 

 any important percentage until July, the month of maximum con- 

 sumption. In this respect this bird appears to differ, like the bobolink, 

 from most other species, as August is usually the month in which 

 grasshoppers are eaten most freel}^; but the examination of a larger 

 number of stomachs might prove the yellowhead to be no exception to 

 the usual rule. After August the consumption of grasshoppers is 

 considerably increased, and the total for the season is 11.6 percent. 

 The remainder of the animal food, 9.7 percent, is made up of other 

 insects, chiefly Hymenoptera (ants, wasps, etc.), with a few dragon- 

 flies and an occasional spider and snail. 



So far as its animal food is concerned, the j'-ellowhead has a very, 

 good record. For a ground feeder, it takes very few predaceous 

 beetles, while insects harmful to vegetation constitute 30 percent of 

 its food. 



The vegetable food consists almost entirely of seeds, and for eco- 

 nomic purposes may be divided into grain and weed seed. Of grain, 

 oats hold first place, as in the food of the redwing, and are probably 

 eaten in every month when they can be obtained, although none were 

 found in any of the 5 stomachs taken in September. The 3 October 

 stomachs contained an average of 63 percent, but a greater number of 

 stomachs would in all probability give a smaller average. August, 

 apparently the next month of importance, shows 43.2 percent. Next 

 to oats corn is the favorite grain, and was eaten to the extent of 9.8 

 percent, nearly all in the months of April, May, -and June, with a 

 maximum of 48.8 percent in April, when no wheat was eaten. Wheat 

 appears from May to August, inclusive, and is the only vegetable 

 food that reaches its highest mark in August. The average for the 

 season is 3. 5 percent. 



Grain collectively amounts to 38.9 percent, or considerably more 

 than half of the total vegetable food, and more than one-third of all 



