How Well Do Artificial Nests Estimate Success of Real Nests?

Abstract

Artificial nests frequently are used to assess levels and patterns of nest predation, but how well these nests measure rates of predation or trends in predation rates at real nests is unclear. We compared predation rates between 58 active Wood Thrush (Hylocichla mustelina) nests paired with 58 artificial nests designed to resemble Wood Thrush nests. Paired nests were available to the same predator community both spatially and temporally. Rates of nest predation were significantly lower for active Wood Thrush nests (33%) than for artificial nests (64%). Rates of parasitism by Brown-headed Cowbirds (Molothrus ater) also differed between the two groups. Twenty-six percent of active nests and none of the artificial nests were parasitized by cowbirds. During 1993 and 1994, we conducted three artificial nest trials on six study sites per year. Rates of predation were highest in small woodlots and declined with increasing forest patch size consistent with the trend reported for active nests on the same sites. Within sites, rates of predation varied among trials with the amount of variation highest on sites with high predation rates. Our results suggest that although artificial nests should not be used to measure actual rates of nest predation or parasitism, they may be valuable for detecting trends in rates of predation. However, because there are many potential biases associated with the use of artificial nests that may make interpretation of trend data difficult, we recommend using artificial nests primarily in pilot studies or in conjunction with active nests.

Teste do efeito de borda na predação de ninhos naturais e artificiais no Cerrado

“…Porém, em outros trabalhos, essa diferença ocorreu com menor (e.g. AMMON & STACEY 1997, WILSON et al 1998) ou com maior sucesso em ninhos artificiais quando comparados aos naturais (e.g. ROPER 1992ROPER , 2000ROPER , 2003.…”

Predation on artificial nests by marmosets of the genus Callithrix (Primates, Platyrrhini) in a Cerrado fragment in Southeastern Brazil

“…Many authors discussed the validity of using artificial nests to estimate predation rates in nature, since absolute rates of predation on artificial nests have always been suspected to be different from the natural ones (WILCOVE, 1985;WILSON et al, 1998;MOORE;ROBINSON, 2004). Although artificial nests may not reflect absolute predation rates this does not mean that artificial nests are not useful for evaluating events related to predation (ZANETTE, 2002).…”

“…Obviously, artificial nests differ from natural ones in a number of important ways which may influence predation rates, such as size, color, and odor of the nest and eggs, lack of an incubating adult, and absence of nestlings (WILSON et al, 1998); besides, studying natural nests is most likely to accurately reflect the actual predation rates (LYRA-NEVES et al, 2007). However, artificial nests do provide a quick and easy way to conduct a preliminary evaluation of predation rates in a natural environment (LEITE;MARINI, 1999).…”

“…They have a long history of use in reproductive studies, as the number and distribution of nests can be controlled (WILSON et al, 1998;MOORE;ROBINSON, 2004). Many authors used artificial nests to analyze predation on natural bird nests (LEITE; MARINI, 1999;DUCA et al, 2001;ALVAREZ;GALETTI, 2007).…”

Survival chances of ground nests in three different habitats in Krka National Park (Croatia)

“…Experimental nest predation studies have greatly contributed to a better understanding of both breeding success and nest predation (8). Artificial nests have been useful in recording differences in predation rates as a function of habitat, nest and egg characteristics, nest location and density, and seasonal variations (8,9). Differences in predation rate between habitats are also influenced by how birds and predators use those habitats (10).…”