GNATCATCHERS. 87 



investigation of this bird's diet 157 stomachs Avere examined. The 

 birds came from various points about San Francisco Bay, and on the 

 coast from Monterey to Santa Cruz, except one migrant which was 

 taken in the southern part of the State. Only 6 stomachs were 

 collected in April, 5 in October, and 7 in November. In the remain- 

 ing four months 139 were taken, and as they are fairly evenly dis- 

 tributed the results for these months may be looked upon as reason- 

 ably reliable. Examination of the food shows 52 percent of animal 

 matter to 48 percent of vegetable. 



AniTnal food. — The greatest quantity of animal food was eaten in 

 the first and last parts of the season — in fact, the six stomachs col- 

 lected in April contained no trace of vegetable food. The animal 

 matter decreases in each month up to September, in which month 

 only 17 percent was eaten. From this month it increases, and ends 

 with 62 percent in November. Too much reliance should not be 

 placed upon the latter figures, as they were obtained from entirely 

 too few stomachs, and are likely to be modified by the examination of 

 more material. The animal portion of the food is mostly insects and 

 spiders, with some earthworms and sowbugs (Oniscus). 



Useful beetles (Carabidse, Coccinellidae, etc.) amount to less than 

 3 jDercent of the food of the year. Most of them are eaten at the 

 beginning of the season before other insects are common. Other 

 beetles, all more or less harmful, constitute 11 percent of the year's 

 food, and are eaten chiefly the first of the season, decreasing toward 

 fall but with a slight increase at the end. They are pretty evenly 

 distributed among the more common families, and no decided prefer- 

 ence is evident for any. It is probable that the thrush eats any 

 beetles that come in its way, and does not make special efi'ort to find 

 a particular kind. 



Caterpillars form somewhat more than 8 percent of the food, and 

 wdiile they are eaten in every month of the thrush's stay, they are 

 taken much more freely previous to August. During and after that 

 month they cease to be an important element of the diet. The average 

 consumption of the first four months of the season is a trifle over 15 

 percent. Ants and wasps (Hymenoptera), bugs (Hemiptera), flies 

 (Diptera), and grasshoppers (Orthoptera) are eaten by the thrush, 

 although little preference is shown for any one of these except for 

 Hymenoptera in the shape of ants. These are eaten Avith remarkable 

 regularity throughout the season, and form about IG percent of the 

 food. This is the largest insect element in the food of the thrush, 

 and the regularity with which ants are eaten would seem to indicate 

 that they are highly esteemed and especially sought for. 



While these insects do not often make themselves pests by directly 

 attacking fruits and crops, they aid and abet the work of other insects 

 in a way which renders them as bad as the worst of those directly 



