Cover. Due to a chromosomal inversion, male and female white-throated sparrows (Zonotrichia albicollis) occur as two distinct morphs, tan or white. Analyses of behavior and parentage revealed that white and tan males exhibit true alternative reproductive stategies; one morph (tan) invests heavily in mate-guarding and parental care whereas the other morph (white) invests in mate advertisement and the pursuit of extrapair paternity. See Tuttle, pp. 425-432. Photo by V. A. Formica.
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