330 U.S. NATIONAL MUSEUM BULLETIN 23 7 pakt i 



Ira N. Gabrielson (1924) reported on 394 stomachs of which 365 

 were taken during the winter months, October to March, inclusive. 

 Distribution was from Alaska, 5 Provinces of Canada, and 13 States. 

 He says the pine grosbeak "feeds in flocks which usually settle down in 

 one tree or more and feed for some time, making a full meal on one 

 variety of fruit or seed if not disturbed. Local conditions, such as 

 relative abundance and availability, probably govern the selection of 

 food. For example, a series of stomachs from New Hampshire con- 

 tained little except seeds of blackberries (Rubus) and the staminate 

 flower buds of pine. When both gizzard and gullet were examined it 

 was usual to find the gizzard filled with one of these foods and the gullet 

 with the other. * * * Stomachs of a series from British Columbia 

 were filled with seeds of snowberry (S7jmphoricarpos) ." 



Continuing, Gabrielson says winter food was 99.1 percent vegetable. 

 Rubus seeds occurred in 207 stomachs and amounted to 14.37 percent 

 of the winter food. Coniferous buds were found in 166 stomachs and 

 made 24.22 percent. "Both had been taken from many different 

 regions by birds which were collected in every winter month." Other 

 items show high percentages because they constitute the entire content 

 of a few stomachs from one locahty, as snowberry, which amounted to 

 17.3 percent, having been eaten almost exclusively by 69 birds in one 

 place. Weed seeds formed 7.67 percent of the diet, juniper berries 

 and other coniferous seeds 4.15 percent. He lists a great variety of 

 wild fruit, which totaled 14.34 percent. Mast, probably composed 

 largely of beechnuts or acorns, was 5.66 percent. The various forms 

 of animal food listed were nearly all found in coniferous buds and may 

 well have been devoured accidentally with them. 



Gabrielson says the few summer stomachs contained 83.83 percent 

 vegetable food and 16.17 percent animal. The percentage of wild 

 fruit was higher; maple and ash seeds were absent. Grasshoppers, 

 ants, spiders, and caterpillars accounted for 15.08 percent of the total 

 food. There were a few small flies and beetles. 



In Nova Scotia in July Harrison F. Lewis observed a bird eating 

 ripe fruit of Amelanchier, or shad bush. The bird would pick one 

 fruit at a time, manipulate it in its beak, extract and swallow the seed. 

 The outer sldn and attached pulp fell to the ground. A day later his 

 wife watched a male which seemed to be eating scales of rust off a 

 fence-wire. Another bird, in female plmnage, was noted the following 

 day picldng repeatedly at the ground on bare, gravelly soil. There 

 could have been wind-blown seeds present. Another summering bird 

 ate the seeds of mountain holly, Nemopanthys mucronata, in fashion 

 similar to that employed on the shad bush. 



William Youngworth (1955b) mentions seeing a bird splitting the 

 green seed pods and extracting the seeds of a Persian lilac. 



