Success of captive-rearing for a threatened shorebird

Abstract

Captive-breeding and -rearing programs have been widely used for the conservation and recovery of imperiled species, and the success of such programs should be rigorously evaluated. In this study, we assessed the success of captive-rearing for a threatened shorebird, the snowy plover Charadrius nivosus, by comparing the survival and reproductive success of captivereared and wild-reared individuals on the central California coast from 2001 to 2010. We used mark-recapture analysis, implemented in the program MARK, to estimate apparent annual survival (ϕ) and encounter occasion detection probability (p) from capture and sighting data of marked plovers. We compared 3 measures of reproductive success (hatch rate, fledge rate and juveniles fledged per year) using stratified randomization tests based on individual breeding histories where captive-and wild-reared plovers were matched for age, sex and year. Captive-and wild-reared snowy plovers had similar apparent survival and reproductive rates and paired with mates of similar age in their first breeding year. The only exception was that captive males after their first breeding year had lower fledging rates than males from the overall population, but this did not affect the annual productivity rate. We conclude that releasing captive-reared individuals is a valuable part of ongoing efforts to restore the snowy plover population in California, and is also useful in cases where plover nests may need to be salvaged to protect them from oil contamination or other catastrophic events.KEY WORDS: Shorebird · Snowy plover · Captive-rearing · Survival · Reproduction 22: 85-94, 2013 Bart et al. 2007). Two plover species are listed under the United States Endangered Species Act, the piping plover Charadrius melodus and the snowy plover Charadrius nivosus; C. nivosus was formerly treated as a conspecific of C. alexandrinus (Chesser et al. 2011), but the World Conservation Union (IUCN 2012) has not yet accepted this change or designated status for C. nivosus. Both the piping and snowy plover have recovery plans recommending captive-rearing programs to support conservation efforts (USFWS 2003(USFWS , 2007. Plovers are ideal candidates for captiverearing programs because their offspring develop rapidly and have limited need of parental care. Resale or republication not permitted without written consent of the publisher FREE REE ACCESS CCESSEndang Species ResCaptive-rearing programs for plovers have largely been ancillary to in situ conservation management or used on an emergency basis. Captive-rearing methods developed with killdeer Charadrius vociferus chicks (Powell & Cuthbert 1993, Powell et al. 1997 were applied to the Great Lakes population of the piping plover, but a subsequent analysis of this program found that the captive plovers had significantly lower apparent survival rates and breeding success than wild plovers (Roche et al. 2008). Similarly, Goossen et al. (2011) reported significantly lower return rates for captive versus wild piping plovers in Saska...

Evaluating the Impacts of Headstarting on the Critically En-Dangered Spoon-Billed Sandpiper <em>Calidris pygmaea</em>

“…Thus, not a complete clutch like in case of SbS, but only one egg of two was collected for the takahe project [8]. For piping plover [13] and snowy plover [14], abandoned eggs, and for the latter species also chicks were taken. To improve safety of clutches of american oystercatchers, anchoring of artificial eggs was used (mainly against flood), which increased probability of nest survival to hatching from 7-30% in a control group to 71-74% in HS ones [10].…”

“…For released takahe, 14% were resighted 4-9 years after release with no obvious difference in post-release mortality in comparison with birds raised naturally; 8 females and 2 males (sex parity at release) are known to have bred [8]. No significant difference was found in captive and wild reared snowy plovers [14]: apparent survival in the age of 1 year (ca. 36%) and of 2+ years (ca.…”

“…Captive reared snowy plovers had just slightly lower hatching and fledging rates than in naturally raised chicks, and these males fledged fewer offspring in the subsequent breeding seasons that could evidence their lower adaptation capability. For piping plovers, 3-fold lower resighting rates (8-9%) for captive reared birds were reported compared to wild reared ones; however, there could be ecological reasons for that, not just lower survival rate [14]. In black-tailed godwits, 26.6% of yearlings came back to the release site next year [11], and 30.7% of the returnees attempted to breed.…”

“…This approach has been applied to increase productivity of the maleo Macrocephalon maleo [7], takahe Porphyrio mantelli [8], mangrove finch Camarhynchus heliobates [9], as well as of several species of waders, the american oystercatcher Haematopus palliatus [10], black-tailed godwit Limosa limosa [11], black stilt Himantopus novaezelandiae [12], piping plover Charadrius melodus [13] and snowy plover Ch. nivosus [14]. Conservation activities in these cases ranged from simply eggs being moved to a safe place for parentless natural incubation (maleo) to a one-year-long captive-rearing process after artificial incubation (takahe).…”

Evaluating the Impact of Headstarting on the Critically Endangered Spoon-Billed Sandpiper Calidris pygmaea

“…However, HS has been used to increase productivity in the maleo (Macrocephalon maleo) [7], takahē (Porphyrio mantelli) [8], mangrove finch (Camarhynchus heliobates) [9], as well as of several species of waders, such as the American oystercatcher (Haematopus palliates) [10], black-tailed godwit (Limosa limosa) [11], black stilt (Himantopus novaezelandiae) [12], piping plover (Charadrius melodus) [13] and snowy plover (Ch. Nivosus) [14]. Conservation actions in these cases ranged from eggs simply being moved to a safe place for parentless natural incubation (maleo) to a one-year-long captive-rearing process after artificial incubation (takahē).…”