Electrophoretic Variants of Egg White Transferring Indicate a Low Rate of Intraspecific Brood Parasitism in Colonial Cliff Swallows in the Sierra Nevada, California

• Published in: Behavioral ecology and sociobiology 1993-01, Vol.32 (2), p.79-84
• Main Authors: Adrianna P. Smyth, Orr, Bruce K., Fleischer, Robert C.
• Format: Article
• Language: English
• Subjects: Alleles; Animal nesting; Bird nesting; Brood parasitism; Cliffs; Eggs; Female animals; Gels; Genotypes; Swallows
• ISSN: 0340-5443; 1432-0762

The frequency of intranspecific brood parasitism in two colonies of cliff swallows (Hirundo pyrrhonota) nesting in the eastern Sierra Nevada in California was assessed through an electrophoretic analysis of egg white (albumin) proteins. Albumin proteins are maternally derived and are presumed to directly reflect maternal genotype. Thus, a comparison of protein banding patterns produced by eggs collected from a single clutch allows any egg laid by a female other than the putative mother to be detected. Eggs were collected from 13 cliff swallow nests in 1984 and 41 nests in 1987, a total of 54 nests. Of the clutches collected in 1984, one showed evidence of intraspecific brood parasitism, giving a nest parasitism rate of 7.6%. In 1987, one of 41 nests contained a parasitic egg, for a parasitism rate of 2.4%. Over both years combined the rate of intraspecific brood parasitism was 2 of 54 nests, or 3.7%. These parasitism rates are much lower than those estimated for Nebraskan cliff swallows (22-43%) and 2nd-year purple martins (36%). Possible explanations for the discrepancy between parasitism rates in Sierran cliff swallows and other groups of swallows are discussed.