Simulations of wood duck recruitment from nest boxes in Mississippi and Alabama

Abstract

Since the early 20th century, wildlife managers have deployed artificial nesting structures for wood ducks (Aix sponsa) to increase availability of nest sites and local reproduction of the species. However, knowledge is lacking of the effects of nest structure size (i.e., large vs. small; Stephens et al. 1998) and reproductive data (e.g., clutch size, hatch date, duckling survival) on recruitment of wood ducks. We used stochastic simulation analyses to predict recruitment of wood ducks into late summer by analyzing data from a 6-year study of box-nesting wood ducks, and 4-year (Mississippi) and 2-year (Alabama) studies of radiomarked female wood ducks and their ducklings. Our index of recruitment was the number of radio-marked ducklings per nest box that survived until 1 September. Ducklings hatched after 1 June exhibited a 30-day survival probability of 0.29, which was nearly 3 times greater than those hatched before 1 June. In east-central Mississippi, 68% and 65% of total wood duck recruits from large and small boxes, respectively, were hatched and reared from June to August. In western Mississippi, 91% of recruits from each box size also were hatched and reared from June to August. Mean number of wood duck recruits produced from large boxes was greater than small boxes at each study site; each large box in western Mississippi produced approximately 4 recruits on average, whereas small boxes in east-central Mississippi produced approximately 1 recruit. Wood duck recruits in our study resulted primarily from late spring and summer hatched birds in contrast to most Nearctic ducks with adaptive, early nesting to promote recruitment. In Mississippi and similar southern environments, we recommend use of large boxes and cleaning boxes around 1 May after completion of initial nests, and emphasize the importance of late spring and summer duckling production to wood duck recruitment.

Survival and habitat selection of wood duck ducklings

“…Installing nest boxes in inconspicuous locations, or at lower densities, can reduce the probability of nests being parasitized (Semel and Sherman ). We concur with other authors and suggest this relationship deserves further attention (Semel and Sherman , Roy Nielsen et al , Hafen and Koons ), particularly as it relates to nest box placement and management and to the identification of an optimal brood size (Heusmann ; Rohwer and Heusmann ; Davis et al , ).…”

“…Patterns in habitat selection were consistent with previous research that identified use of woody or dense vegetative cover (McGilvrey , Sousa and Farmer , Smith and Flake , Granfors and Flake , Davis et al ). Brood and duckling survival may limit recruitment at our northern study area and additional data collection is required to support life‐cycle analysis (Coluccy et al , Davis et al ).…”

“…Nest box programs can further conservation by providing additional nesting opportunities (Hepp et al , ; Bellrose and Holm ; Kennamer et al ). The success of these programs, however, requires recruitment of birds into the autumn flight and relatively little is known about post‐hatch vital rates and habitat use, particularly at northern latitudes (Davis et al ).…”

“…Researchers often study nest and hatch success to estimate reproductive success, whereas brood and duckling survival are poorly understood despite their importance to recruitment (Hoekman et al 2002, Simpson et al 2005, Davis et al 2007). Habitat also influences survival; therefore, an improved understanding of waterfowl vital rates and habitat use across latitudes would benefit continental waterfowl management and facilitate targeted conservation efforts (Hoekman et al 2004;Davis et al 2007Davis et al , 2015Simpson et al 2007).…”

Predator guards on nest boxes improve nesting success of birds

“…Managers can potentially use our results to inform conservation action, reduce losses of eggs, nestlings and adults to predation, and indirectly promote nest site fidelity by increasing the likelihood of successful nesting. Furthermore, our results support growing evidence that the type of nest box array used in avian research is not trivial and may introduce an unexamined source of variation in reproduction studies (Lambrechts et al , Møller et al , Davis et al , Bueno‐Enciso et al , Demeyrier et al ).…”