Nest‐site limitation and density dependence of reproductive output in the common goldeneyeBucephala clangula: implications for the management of cavity‐nesting birds

Abstract

Summary1. Hole-nesting birds are frequently faced with a shortage of suitable nest sites in regions of intensive forest management. Nest boxes are sometimes provided to alleviate nest-site limitation in cavity-nesting waterfowl and are also recommended for several rare and endangered species. However, the impacts on effective breeding numbers and breeding success have rarely been considered, particularly in instances where density dependence might operate. 2. We experimentally manipulated nest sites to assess limits on the population size of a secondary cavity-nesting species, the common goldeneye Bucephala clangula, living on freshwater lakes. We also examined density dependence in their reproductive output. 3. Breeding pairs were counted in experimental and control areas over a 12-year period; for 4 years (1988-91) before nest box addition (1992-94 in the experimental area) and for 5 years (1995-99) afterwards. Broods were counted each year between 1988 and 1999 to study reproductive output. 4. Mean number of pairs per lake increased after the addition of nest boxes in the experimental area but not in the control area. However, neither the mean number of broods per lake nor the mean number of fledged birds per lake increased significantly in the experimental area. 5. When the whole period of 1988-99 was considered and data pooled from all the lakes, the numbers of broods and fledged birds showed negative density dependence of reproductive output. 6. Our results indicate that nest sites limit the population size of breeding common goldeneye, but show also that density-dependent factors operate to limit reproductive output. The possibility that density dependence may negate management actions directed at increasing breeding numbers in cavity-nesting waterfowl should be considered carefully before taking these actions. This also applies to nest box provisioning programmes aiming to manage populations of endangered species.

Nest Boxes Facilitate Local-Scale Conservation of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) in Alberta, Canada

“…Locating natural cavity nests can be challenging in some habitat types (e.g., Vaillancourt et al 2009), population density can be colimited by other factors, e.g., intraspecific competition for food, birds can switch from occupying natural nesting sites to artificial boxes (e.g., Gauthier and Smith 1987), or nest box deployment can coincide with other larger scale, sometimes continental, factors that dictate population sizes. Few studies have attempted to demonstrate using experimentation the connection between various measures of breeding activity, the availability of nest boxes, and whether nest box deployment influence population size (Savard 1988, Newton 1994, Pöysä and Pöysä 2002.…”

“…Observed reductions in numbers of broods and brood sizes in 2004 because of nest box closure were not accompanied by estimates of population size on the Buffalo Lake Moraine. Rigorous examinations of linkages between availability of nesting sites and population size require substantive experimental designs where the manipulation occurs across large spatial scales and over multiple years, and have been rarely completed (but see Pöysä and Pöysä 2002). Our study provides indirect evidence that nest box deployment influences population sizes of Bufflehead and Common Goldeneye by demonstrating (1) 3-to 10-fold reductions in numbers of broods and brood sizes because of nest box closure, (2) increases in occurrence and density over a 16-year period coinciding with nest box deployment, and (3) local increases in populations of the two species on Buffalo Lake Moraine that were not simple manifestations of increases in the size of regional populations.…”

“…Nest boxes are widely used to enhance populations of cavity-nesting species including waterfowl (Savard 1988, Newton 1994, Pöysä and Pöysä 2002, Savard and Robert 2007, passerines (Nilsson 2008), sea birds (Bolton et al 2004), and marsupials (Lindenmayer et al 2009). The effectiveness of nest boxes is determined by a variety of factors including design (García-Navas et al 2008), adjacency to key resources (Aitken and Martin 2004), predation (Brightsmith 2005), nest defense behavior (Rosvall 2008), reproductive output of targeted species (Mátics et al 2008), and the extent that territoriality limits density (Duckworth 2006).…”

Costs of Reproduction in Breeding Female Mallards: Predation Risk during Incubation Drives Annual Mortality

“…Nest sites and the relative safety they provide to eggs, nestlings, and attendant adults are an important component of life-history strategies in birds (Martin and Li 1992) and have also been important targets for conservation efforts (Eskowich et al 1998, Pöysä and Pöysä 2002, Arnold et al 2007). Mallards (Anas platyrhynchos) have highly flexible nest-site selection, but the vast majority of females nest on the ground in upland habitats, thereby exposing themselves to a large suite of terrestrial mammalian predators to which they are otherwise immune (Sargeant et al 1993).…”

The Abundance of Tree Holes and Their Utilization by Hole-Nesting Birds in a Primeval Boreal Forest of Mongolia

“…Hole-nesting birds are considered as one of the most susceptible groups to such impacts due to their strong dependence on trees (Angelstam & Mikusiński 1994, Martin & Eadie 1999, Imbeau et al 1999. It has been suggested that the availability of nesting holes limits the population density of such birds in many managed forests (von Haartman 1957, Johnson 1994, Newton 1994, Semel & Sherman 2001, Twedt & Henne-Kerr 2001, Pöysa & Pöysa 2002. Since the 1990s, with the emergence of ecological forestry, there is an increasing need to improve our understanding of biodiversity and its maintenance in natural forests, so that such knowledge can be incorporated into management guidelines (Hansen et al 1991, Fujimori 2001.…”