Bird populations -- United States, Avian biology
Understanding why brood parasites lay eggs in the nests of hosts that reject eggs is hampered by insuf-ficient data on the frequency with which parasites lay in rejecter nests, and by ignorance of which in-dividuals practice this seemingly inappropriate be-havior. Parasitism rates of rejecters can be deter-mined only when host nests are observed during egg laying because most parasite eggs are rejected rapidly (e.g. Scott 1977). Even then, however, a certain per-centage of parasitized nests may go undetected. De-termining the selective value of host defense mech-anisms also depends on knowledge of the frequency of parasitism, and the amount of reproductive loss caused by parasitism when it occurs (Rothstein 1976a).
Murphy, M. T. (1986). Brood parasitism of eastern kingbirds by brown-headed cowbirds. The Auk, 626-628.