Two Instances of Kleptoparasitism in Passerines
Kleptoparasitism among passerines is rare. We report two instances of kleptoparasitism, one with an adult Worm eating Warbler (Helmintheros vermivorus) acting as a kleptoparasite on a female Black and white Warbler (Mniotilta varia) and one with a male Indigo Bunting (Passerina cyanea) acting as a kleptoparasite on a female Worm eating Warbler. In both instances parents were disturbed while feeding fledglings. This combination may occur infrequently, which would explain why kleptoparasitism is rarely observed among small passerines.
Journal of Field Ornithology
Kellner, C. J. and Cooper, R. J. (1998). Two instances of kleptoparasitism in passerines. Journal of Field Ornithology, 69(1): 55-57.