WESTERN WOOD PEWEE 283 



Eggs. — The western wood pewee usually lays three eggs, sometimes 

 only two, and very rarely four. These are indistinguishable from 

 those of the eastern wood pewee, which the reader will find described 

 under that bird. The measurements of 50 eggs average 18.3 by 13.6 

 millimeters; the eggs showing the four extremes measure 19.5 by 

 13.2, 19.1 by 15.0 and 16.0 by 13.0 millunetcrs. 



Young. — The incubation period is probably about 12 days. The 

 female evidently does all the incubating, but the male assists in the 

 care of the young. Probably only one brood is raised in a season - 

 Mrs. Wheelock (1904) implies that the male does most of the feeding 

 of the young, and says: "Small butterflies, gnats, all sorts of small 

 winged insects are the orthodox food for infant flycatchers, and are 

 swallowed at the rate one every two minutes. Nor does the supply 

 ever quite equal ths demand, for every visit of the devoted father is 

 welcomed with wide-open mouths and quivering wings. At first 

 all this feeding must be by regurgitation, the adult swallowing the 

 insect first and partially digesting it in some cases, and in others 

 merely moistening it with the saliva. After four or five days most 

 of the food is given to the young in a fresh state." 



Plumages. — I can find nothing in the molts and plumages of the 

 western wood pewee that are in any way different from those of the 

 eastern wood pewee ; all that has been said about the eastern bird will 

 apply equally well to the western. 



Food. — Professor Beal (1912) reports on the contents of 174 stom- 

 achs of the western wood pewee, in which 99.93 percent of the food 

 was animal matter and only 0.07 percent vegetable. Beetles of 19 

 species amount to 5.44 percent, of which only 0.95 percent are useful 

 beetles, ladybird beetles, and predaceous ground beetles. Hymenop- 

 tera, wasps, bees, and ants amount to 39.81 percent of the food and 

 were found in 107 stomachs, 17 of which contained no other food. 

 Parasitic species were noted in 8 stomachs and ants in 10. No trace of 

 a honeybee was found, and he never heard any complaints against 

 the bird on this score. Diptera (flies) seem to be the largest item of 

 the food, amounting to 44.25 percent. They were found in 162 stom- 

 achs, 30 of which were entirely filled with them. Tliey included horse 

 flies, snipe flies, crane flies, robber flies, and house flies. Hemiptera 

 amount to only 1.79 percent, and no trace of grasshoppers or crickets 

 was found. Moths were found in 24 stomachs and caterpillars in 5, 

 making an average of 5.17 percent for the season. Dragonflies, lace- 

 winged flies. Mayflies, white ants, and spiders together make up 3.47 

 percent, the remainder of the animal food. 



Vegetable matter was found in only four stomachs. "In one of these 

 it consisted of 3 seeds of elderberries {Sanibucus) ; in another, of a bit 

 of fruit skin, with a trifle of rubbish; in another, of one seed of wild 

 oats; and in the fourth, of rotten wood." 



