FOOD HABITS OF SOME WINTER BIRD VISITANTS. 17 



The pine siskin hulled the seeds eaten more consistently than 

 any other bird considered in this bulletin, and consequently 34 

 stomachs were found in which the hulled and finely divided seed 

 fragments could not be identified. This material constituted the 

 remaining 20.15 per cent of the 86.7 per cent of vegetable matter 

 in the winter food. 



Of the 13.3 per cent animal matter in the winter food, caterpillars, 

 found in 17 stomachs to the extent of 7.31 per cent of the total, were 

 the most important single item. Four November stomachs collected 

 at Rockaway Beach, NT Y., were filled with tortricid larvae (leaf- 

 rollers). Eleven birds, collected in various parts of the country in 

 April and May, had fed chiefly or entirely on caterpillars, while six 

 had taken plant-lice (Aphididae) to the extent of 1.38 per cent of 

 the food. One California bird had eaten more than 300 plant-lice, 

 which formed 42 per cent of the stomach contents. A bird taken in 

 North Carolina, during an outbreak of grain aphids had fed exclu- 

 sively on them, 80 being counted. Two others had made 98 and 100 

 per cent of their food of plant-lice. The stomach contents of seven 

 birds taken in one locality in California during March and April 

 averaged 90 per cent black olive scales (Saissetia oleae), a very de- 

 structive pest of the olive. In March over 12 per cent of the total 

 food was made up of this insect, and it constituted 2.17 per cent of 

 the total food for the season. The remaining 2.44 per cent of insect 

 food consisted of fragments of beetles, grasshoppers, and other 

 insects. 



Summer food. — The 25 stomachs collected in the four months from 

 June to September came from widely separated localities, mostly 

 from the mountainous regions of the West. Animal matter formed 

 28.08 per cent of the contents of these, and vegetable matter 71.92 

 per cent. Three birds had eaten plant-lice, which constituted 8.48 

 per cent of the food for this season; two, one of which had eaten 

 nothing else, had taken caterpillars to the extent of 4.68 per cent of 

 the food, and the remaining 14.92 per cent of animal matter consisted 

 of spiders, bugs, fly larvae, weevils, and other insects. 



Of the vegetable food, coniferous seeds formed 20 per cent, weed 

 seeds 19.2 per cent, and miscellaneous plant matter from a number 

 of stomachs in which the contents were very finely divided, 32.72 per 

 cent. 



Various seeds other than those found in the stomachs examined 

 have been mentioned in ornithological literature as constituting part 

 of the food of the pine siskin. Among these are seeds of sweetgum 

 (Liquidamoar sty rati flua) , willow (Salix), juniper (Juniperus), 

 and plantain (Plcmtago). Buds also are occasionally eaten, this 

 habit causing the only complaint recorded against the species. This 

 occurred in 1886, when a large number of pine siskins appeared in 

 one locality in Oregon and fed extensively on the buds of fruit trees. 

 No other charges have been made against the species on this ground, 

 so that it seems safe to assume that this is not a regular habit of the 

 bird but a local occurrence caused by unusual conditions. Normally 

 the siskins are rarely present in sufficient numbers to do extensive 

 damage, even if the bud-eating habit were much more highly devel- 

 oped than is now apparent. 



