58-t (iAME BIKDS OF CALIFORNIA 



As already intiumted, tlic aiuount of food available to the pigeon 

 appears to be the main controlling factor in its distribution, aside from 

 the zonal considerations which apply during the breeding season. This 

 is more particularly true in winter, though probably to some extent 

 in summer also. As will be observed from the following data, the 

 food consists chiefly of berries and nuts, and the plants which bear 

 these are of intermittent productiveness. A large crop one year in 

 a certain region is almost sure to be succeeded by a poor one the fol- 

 lowing year, so that the pigeons would fare scantily if dependent alto- 

 gether on any one locality. Their proclivity to circulate over large 

 areas makes available to them abundant crops recurring at different 

 places. The birds are thus able to find support in great numbers some- 

 where all the time. 



Out of twenty-two records mentioning their food, ten give acorns 

 as the chief article of diet. Probably all the species of oaks are 

 patronized by the pigeons. Those specifically recorded are : in west- 

 central and southern California, the live oaks (Quercus agrifolia and 

 Q. u'isliscnii), in the foothill regions, the golden oak {Quercus chry- 

 solepis), and along the Sierra Nevada and on the San Bernardino and 

 San Jacinto mountains, the black oak (Quercus kelloggii). The acorn 

 season lasts well through the autumn months, and under favorable 

 circumstances even until February. 



As M'ith all the other articles of food consumed by these birds, the 

 acorns are swallowed whole, and in such numbers that at feeding time 

 the crop becomes enormously distended. Here the food is acted iipon 

 by powerful digestive juices, and both shell and kernel rapidly dis- 

 integrate and pass on to the stomach and gizzard. There is no dis- 

 gorgement of hard parts of the food, as with some birds. Considering 

 the apparently small size of its mouth, the pigeon's ability to swallow 

 entire such relatively huge objects as tlie acorns of the golden oak 

 is amazing. One dropped by a bird in flight measured about one by 

 one and one-half inches (A. M. Ingersoll, in letter). It is reported 

 (Van Rossem. 1914, p. 146) that pigeons have been found in a dying 

 condition, their crops pierced by acorns which they had swallowed. 



In the coast region of central California the berries of the madrone 

 {Arhntus mrmiesii) form an attractive food source in the fall of the 

 year. In certain instances bauds of {)igeons have been known to stay 

 around tracts of madrones until practically every berry had been 

 taken. Sometimes the birds feed so largely on these berries that 

 their flesh becomes discolored thereby (Jenkins, 1906, p. 126). 



When the acorn crop is small or has become exhausted, the birds 

 resort to the apple-like fruits of certain species of manzanita (Arcto- 

 staplrylos) , eating them from the time they are first formed and green, 

 until late fall when they are fully ripe. In early October, 1915, large 



