ABSTRACT
Shorebirds run the gamut of breeding system diversity, with the plover lineage being no exception. Inter- and intraspecific variation in mating and parental strategies has been documented throughout the group, thus providing a model system with which to conduct theoretical and empirical research in the fields of evolutionary biology and behavioral ecology. Here, I review mating strategies and patterns of parental care from plover populations worldwide. In summary, I found that 77% of the 40 plover species were monogamous with biparental care during incubation and brooding, 18% were polygamous or exhibited uniparental care, and the remaining 5% were of unknown status due to insufficient study. Notably, in species with uniparental care, parental desertion (typically by females) occurs during brood rearing, which is likely related to the independent nature of their precocial young. Furthermore, extra-pair mating in plovers is low (0%–9.1% of broods with mixed parentage) compared to other avian taxa, probably owing to the importance of maintaining male involvement during parental care. Local demographic and ecological variation in the environment appears to play a strong role in shaping breeding system expression: adult sex ratio variation is related to parental desertion, presumably via sex-biased mating opportunities, whereas harsh climates impose parental cooperation during care, thus restricting the potential for polygamy. I illustrate these associations with a case study exploring adult sex ratio variation and breeding system expression among six plover populations from around the globe. Lastly, I discuss the importance of integrating breeding system variation into plover conservation and management. Monogamous populations can be vulnerable to inbreeding depression owing to limited gene flow, whereas polygamous populations are characterized by sex-biased effective population sizes vulnerable to density-dependent growth. Effective recovery plans will require routine monitoring coupled with behavioral ecology, demography, and population genetics.
