508 U.S. NATIONAL MUSEUM BULLETIN 23 7 part i 



Food. — It seems to be the accepted idea that the principal food of 

 the crossbill consists of the seeds of conifers, and various accounts of 

 how the bird uses its specialized bill to extract these seeds from the 

 cones have been published by the earlier writers. C. A. Robbing 

 (1932), with Winsor M. Tyler, made some careful observations at 

 close range of a captive crossbill's method to open the scales and 

 extract the seeds. As their account is too elaborate to be included 

 here, the reader is referred to the above paper for details. Their 

 observations agree in some details with the earlier writers and differ 

 from them in others. Briefly the method "plainly shown us by our 

 bird, involves the use of two appliances; the hill, which forces and 

 holds apart the scales; and the tongue, which lifts the seeds out." 



Crossbills eat the seeds from the cones of various pines, firs, spruces, 

 hemlock, and larch. They also eat the seeds of birches, alders, box 

 elders, elms, ragweed, hemp, and probably other weeds. At times 

 they feed on the buds of birches, alders, willows, poplars, elms, and 

 maples, as well as the tender, green buds of spruces. 



Perley M. SUloway (1923) says: "The Crossbills eat the seeds from 

 the birch catkins in two different ways. Sometimes they cling to the 

 terminal twigs where the cones are attached and bite out mouthfuls 

 of seeds, often standing with head down in their endeavors to reach 

 the catkins, and detaching seeds with their crossed, forcep-like man- 

 dibles, and many seeds fall wasted to the ground. Usually, however, 

 they bite off the cones one at a time, holding them against a branch 

 with their feet, and munch on it in a leisurely manner." 



Prof. O. A. Stevens of Fargo, N. Dak., writes me in a letter: "A 

 number of people reported the birds, usually feeding on sunflowers. 

 We had a few sunflowers in the garden. Once I saw a cat jump up and 

 seize one of the birds as it clung to a sunflower head about two feet 

 above the ground." 



CrossbUls also eat insect food — caterpillars, plant lice, larvae of 

 insects, beetles, ants, etc. Ora W. Knight (1908) observed "several 

 Crossbills engaged in eating larvae of Vanessa antiopa and the small 

 green lice which were numerous. I have also seen them picking apart 

 the cottony colonies of lice which are always found in bunches of 

 alders in late summer, and most certainly eating something they took 

 from the cottony bunches. 



"Lumbermen have told me of instances where the CrossbUls were 

 seen feeding on the material left in salt pork barrels tlirown outside of 

 the camps." 



P. A. Taverner (1934) writes: "They seem specially fond of the little 

 woolly aphis. It was very interesting to watch a captive specimen 

 open galls on poplar leaves. Seizing the fleshy tissue with the bill 

 tips so that the points crossed within the mass, it gave a little twist of 



