Artificial incubation, egg replacement and adoptive parents in bird management: a test with Lesser ElaeniaElaenia chiriquensis

Abstract

SummaryReducing the time that birds' eggs are exposed during incubation in the wild is a management strategy with the potential to reduce nest predation rates, enhance breeding success and increase the population size of endangered species. We tested whether manipulation of clutches through artificial incubation of Lesser Elaenia Elaenia chiriquensis eggs and subsequent reintroduction of new-born nestlings to their original nest, and the use of adoptive parents, were efficient ways of increasing the population size of this species. We evaluated the financial cost and benefit of three different management strategies of artificial egg incubation with reintroduction of nestlings to the original nest. We searched for nests and manipulated eggs during the breeding seasons of 2009 and 2010 in a savanna reserve in central Brazil. Real eggs were replaced by artificial eggs and artificially incubated. The following breeding parameters were monitored: hatching rate, fledgling productivity, daily survival rate of nestlings and nest success. The effect of nest monitoring frequency (daily or every 3-4 days) on breeding parameters was also tested. Hatching rate was much higher amongst artificially incubated eggs than naturally incubated eggs. Artificially incubated clutches presented higher rates of fledgling production and apparent nest success than non-manipulated clutches. Clutch manipulation did not interfere with nestling daily survival rate. Daily monitoring did not have negative effects. The clutch manipulation methodology we used proved to be viable and is a potential tool for increasing population size.

Assessing conservation tools for an at-risk shorebird: Feasibility of headstarting for American OystercatchersHaematopus palliatus

“…For example, eggs of Common Terns Sterna hirundo have a thin cuticle that appears to promote moisture loss during development (Klimsta et al 2009). High rates of hatching during artificial incubation appear to be common among wild birds across an array of taxa once incubation settings are optimised (Kuehler et al 1993, 2001, Powell et al 1997, Lobo and Marini 2013). However, incubation settings for wild birds are not well understood and natural incubation temperature and humidity are often not known or difficult to measure precisely in the field (Gonzalez-Garcia et al 2006, Klimstra et al 2009).…”

“…splay legs or ectopic viscera). It is, however, not uncommon for avian parents to abandon unhealthy chicks and therefore this behaviour may not be directly related to headstarting (Lobo and Marini 2013). Whether chicks were placed in original or foster nests did not affect acceptance by parents.…”

“…Whether chicks were placed in original or foster nests did not affect acceptance by parents. Acceptance of foster chicks appears to be common among many birds for which artificial incubation and chick placement has been attempted (Reed et al 1993, Lobo and Marini 2013). Adults may not, however, accept foster chicks if they are returned to the nest before the anticipated hatch date of original eggs.…”

“…Adults may not, however, accept foster chicks if they are returned to the nest before the anticipated hatch date of original eggs. Therefore, nests of the appropriate age need be available for fostering and anticipated hatch dates need to be known (Lobo and Marini 2013). Cross-fostering may not be suited for small populations with high degrees of laying asynchrony (Lobo and Marini 2013).…”

“…One tool that has received considerable attention for the management of declining or threatened avian populations is headstarting, or the artificial incubation of eggs and subsequent placement of newly hatched chicks in original or foster nests. Also referred to as ‘hatch-and-switch’, headstarting has been used in various forms for cranes, shorebirds, passerines and other endangered birds (Powell et al 1997, Robertson et al 2005, King et al 2013, Lobo and Marini 2013) and has also been employed for the conservation of iguanas (Perez-Buitrago et al 2008, Escobar et al 2010). Headstarting appears to be most effective as a tool to avoid likely nest failures when productivity is lost during incubation and when parents can be enticed to remain at nests through the placement of artificial eggs (Elliott et al 2001).…”