Costs and benefits of brood desertion in female kentish plovers, Charadrius alexandrinus

Abstract

Female kentish plovers Charadrius alexandrinus typically desert their broods after the chicks hatch, i.e. 14 weeks before the chicks fledge or become independent. In this paper we investigate the costs and benefits of desertion for females. Desertion incurs a cost for females: following desertion chick survival in broods is lower (0.95 + 0.02 day -1) than before the female deserts (0.98 + 0.01 day-l). We investigated several possible causes for reduced brood survival by comparing characteristics of broods before and after desertion (controlling for differences in brood age). After desertion males increased the time they spent foraging and they tended to reduce time spent brooding chicks. Increased mortality of chicks may occur in deserted broods because following desertion (1) males spend less time alert in vigilance behaviour than before desertion, (2) they attend the chicks from greater distances, and (3) they show greater distraction display distances (in response to human intruders). Growth or development of chicks, measured by weight gain and tarsus length, was not different before and after desertion. Females gain two potential benefits from desertion: (1) they may remate and produce a second brood within the same breeding season or (2) they may enhance their probability of surviving to breed in a subsequent season. At least 27% of female kentish plovers that deserted remated and renested in the same season in this study. In contrast, we found no evidence that brood desertion increased the survival of females: there was no difference in local survival rate (return rate) for females deserting before or after 6 days brood age.These results clearly demonstrate that female kentish plovers that desert their offspring prior to fledging incur costs, but we suggest that there is a trade-off with the potential benefits gained by remating and making a second breeding attempt in the same season.

Mate fidelity in a polygamous shorebird, the snowy plover (Charadrius nivosus)

“…We suggest that in snowy plovers, divorce is result from their effort to maximize reproductive output during a given time period. The birds' urge to re-mate as many times as possible within a breeding season and produce the highest possible number of chicks could be traded off by lowered survival of their abandoned broods although, given the precociality of the young, this cost may not be prohibitive (Székely & Williams, 1995).…”

Social Polyandry, Parental Investment, Sexual Selection, and Evolution of Reduced Female Gamete Size

“…Social polyandry has been discovered in pipefishes (Syngnathidae; e.g., Berglund et al 1989;Jones et al 2001;McCoy et al 2001) and in several avian families (Oring 1986). It has been studied in detail in shorebirds (Charadriidae and Scolopacidae; e.g., Hildén and Vuolanto 1972;Jenni and Collier 1972;Schamel and Tracy 1977;Oring and Lank 1982;Oring et al 1983Oring et al , 1997Lessells 1984;Lank et al 1985;Reynolds 1987;Page et al 1995;Székely and Williams 1995;Reed and Oring 1997;Emlen et al 1998;Amat et al 1999Amat et al , 2001Butchart 2000). In some respects, social (also called classical) polyandry remains the least understood breeding system (e.g., Jenni 1974;Emlen and Oring 1977;Ridley 1978;Erckmann 1983;Oring 1986;Andersson 1994;Reynolds 1996;Ligon 1999;Owens 2002).…”

Does predation danger on southward migration curtail parental investment by female western sandpipers?

“…By comparison with the phenology of the ecologically-similar Pacific dunlin, we estimate that western sandpipers could have remained on the breeding grounds and continued breeding activities for a further 8.8d (2004) to 1.0d (2006). We assume that this represents foregone opportunity by western sandpipers that could have been used to improve offspring survival [32,33], or for more renesting or perhaps double brooding, both of which are highly expressed by Pacific dunlins [28].…”