BANK SWALLOW 413 



at this time have their secondaries tipped with white. The post- 

 juvenal molt takes place after the birds arrive at their winter quar- 

 ters. The first winter plumage, according to Dwight (1900) has the 

 tail more deeply forked and is indistinctly barred, the chin is pure 

 white without spots and the collar is darker. The young and adults 

 become indistinguishable. 



The first nuptial plumage is acquired by wear. The wings and 

 tail are darker than those of the juvenal plumage. The upper parts 

 are a lusterless grayish brown, darker on the pileum. Feathers of 

 the rump, scapulars, tertials, and upper tail coverts have paler mar- 

 gins except in midsummer. AVings and tail are fuscous, underparts 

 white interrupted by a broad band of grayish brown across the 

 breast, which is continued along the sides; bill brownish black; iris 

 brown, legs and feet dusky horn color. There is a small tuft of 

 feathers on the tarsus near the base of the hind toe. 



The sexes are alike in their plumages and molts, and there is but 

 little variation with age. The adult winter plumage, according to 

 Dwight (1900), is acquired by a complete postnuptial molt, which 

 is assumed after the birds have moved southward in the winter. The 

 adult nuptial plumage is acquired by wear. 



Abnormal plumages such as albinism, a condition where there is 

 an absence of pigment in the feathers, occurs in many gi-oups of 

 birds. Wliile this condition is not common it may be expected in any 

 species. On June 2, 1932, I noted a pure-white albinistic bank swal- 

 low among the members of a large colony near Topsham, Maine. It 

 was seen three days later and then disappeared. As far as I was 

 able to discover this individual was not nesting. 



Food. — The bank swallow is primarily insectivorous. Vegetable 

 matter such as seeds occurring in the stomach contents is purely 

 accidental. 



F. E. L. Beal (1918) found in the examination of 394 stomachs of 

 bank swallows collected in 21 States and Canada that 17.9 percent 

 of the food consisted of Coleoptera. Of these. May beetles, flea 

 beetles, and the various species of weevils that have proved destruc- 

 tive to many crops were most numerous. Arthur H. Howell (1924) 

 reports that 25 bank swallows taken over the cottonfields of Texas 

 in September had eaten 68 boll weevils, one bird having eaten 14 of 

 them. 



Ants, chiefly winged forms, composed 13.39 percent of the food in 

 the stomachs examined by Beal. The ants were found in 121 stom- 

 achs and formed the total contents of 11 of them. Various other 

 species of Hymenoptera were found in 207 stomachs. The 

 Hemiptera, chiefly leafhoppers, treehoppers, and plant lice, com- 

 prised nearly 8 percent of the food, but this amount of Hemiptera 

 is small as compared to that eaten by the other species of swallows. 



