Removing American crows and duck nesting success

Clark, Robert G.; Meger, Daryl E.; Ignatiuk, Jordan B.

doi:10.1139/z95-059

Cited by 24 publications

(14 citation statements)

References 20 publications

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“…First, biases in reporting may influence the dataset since studies reporting a null effect can be difficult to publish (Csada et al 1996). Only 15 of the 112 studies presented report no significant increase (or decrease) in fecundity following predator removal (''Appendix 1''; Bolton et al 2007;Clark et al 1995;Dion et al 1999;Flux et al 2001;Garretson et al 1996;Harper 2007;Kauhala 2004;Powlesland et al 2003;Rohwer et al 1997). Second, there may be unusual or idiosyncratic circumstances that are not anticipated by the model.…”

Section: Discussionmentioning

confidence: 99%

Bird demographic responses to predator removal programs

2010

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Invasive predators pose a significant risk to bird populations worldwide. Humans have a long history of removing predators from ecosystems; current island restoration actions typically focus on the removal of invasive predators, such as non-native rodents, from seabird breeding islands. While not overly abundant, the results of predator removal studies provide valuable information on the demographic response of birds, and can assist conservation practitioners with prioritizing invasive predator removal projects. We review such studies focusing on observed demographic responses of bird populations to predator removal campaigns and whether ecological factors are useful in predicting those responses. From the 800? predator removal programs indentified, a small fraction (n = 112) reported demographic responses of bird populations. Change in productivity was the most commonly reported response, which on average increased by 25.3% (2.5 SE) with predator removal. The best supported model for predicting the change in productivity from predator removal incorporated bird body mass, egg mass, predator type, nest type and an interaction term for body mass and nest type (AIC c weight = 0.457). The predicted percent increase in productivity resulting from hypothetical predator removal ranged from 16.9 to 63.0% (mean = 45.0, 5.6 SE), and was lowest for large, surface nesting birds such as albatrosses. The predicted increase in productivity resulting from predator removal alone was insufficient to reverse the predicted population decline for 30-67% of bird species considered, suggesting that in many cases, removal of predators must be performed in combination with other conservation actions in order to ensure a stable or increasing population.

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Section: Discussionmentioning

confidence: 99%

Bird demographic responses to predator removal programs

2010

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“…We believe that reducing nest predation has been neglected as a management option for increasing songbird productivity (but for game birds see Clark et al 1995;Tapper et al 1996), perhaps because nest predation is ubiquitous or because of parasitism's high profile as a contributing factor for the near-extinction of several songbirds. Regardless, nest predation is a major cause of poor reproductive performance in songbird populations.…”

Section: Amelioration Of Nest Predation and Brood Parasitismmentioning

confidence: 99%

“…In the absence of predator control, parasitism control (e.g., see Robinson et al 1993) often will be minimally effective. As a result, identifying and manipulating habitat features that reduce nest predation and brood parasitism represents the best long-term solution (Martin 1992;Clark et al 1995). Unfortunately, predator control may not be as simple as controlling populations of the major predator species.…”

Section: Amelioration Of Nest Predation and Brood Parasitismmentioning

confidence: 99%

The Relative Impacts of Nest Predation and Brood Parasitism on Seasonal Fecundity in Songbirds

Schmidt

Whelan²

1999

Conservation Biology

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The impacts of nest predation and brood parasitism on the seasonal fecundity of birds are strongly dependent on the number of nesting attempts, and thus seasonal fecundity is responsive to behavioral traits that increase the number of opportunities to nest. We developed simple models to investigate the relative impacts of nest predation and brood parasitism on seasonal fecundity in songbirds. In particular, we asked to what extent songbirds can ameliorate the negative effects of high nest predation and brood parasitism often typical of fragmented, urbanized, and agricultural landscapes through (1) renesting following predation, (2) abandoning and renesting following parasitism, and (3) double brooding-renesting following a successful brood. Our model assigned probabilities to all possible fates of breeding females and calculated seasonal fecundity by summing up the individual probabilities. We analyzed the model through the use of fecundity isopleths, which allow one to visually determine the impact of predation and parasitism simultaneously over the entire range of probabilities. Our analysis indicates that (1) nest predation has a greater impact on seasonal fecundity over a larger range of parameter space than does parasitism, especially when brood loss due to parasitism is low; (2) songbird populations experiencing nest predation probabilities typical of fragmented landscapes ( Ͼ 0.65) are unlikely to be self-sustaining; and (3) amelioration of nest predation through frequent renesting or double brooding may be insufficient to establish self-sustaining populations. These results suggest that predator control should be at least as high a priority as parasitism control, particularly for species that suffer moderate to low brood reduction due to parasitism and that are single-brooded. Programs aimed solely at managing cowbirds likely will be of limited success. Impactos Relativos de la Depredación de Nidos y el Parasitismo de Nidada en la Fecundidad Estacional de Aves Cantoras Resumen: Los impactos de la depredación de nidos y el parasitismo de nidadas en la fecundidad estacional de aves son fuertemente dependientes del número de intentos de nidación y por lo tanto la fecundidad estacional es una respuesta a las tendencias conductuales que incrementan el número de oportunidades para anidar. Desarrollamos modelos simples para investigar los impactos relativos de la depredación de nidos y el parasitismo de nidadas en la fecundidad estacional de aves cantoras. En particular, evaluamos a que grado las aves pueden atenuar los efectos negativos de la alta depredación de nidos y el parasitismo de nidadas que son frecuentemente típicos en paisajes fragmentados, urbanizados y agriculturales, mediante: 1) reanidación después de una depredación, 2) abandonando y reanidando después de un parasitismo, y 3) doble nidada (i.e. reanidando después de una nidada exitosa). Nuestro modelo asigna probabilidades a todas las posibles opciones de hembras reproductivas y calcula la fecundidad estacional mediante la suma de probabilidades...

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“…Bolton et al 2007). However, investigations of partial predator removal have consistently demonstrated that, as predators rarely act in isolation, removal of one species can lead to compensatory predation by other, uncontrolled species (Parr 1993, Clark et al 1995, Dion et al 1999. This interaction among predators is frequently cited as an explanation for the apparent lack of long-term benefits of predator control.…”

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confidence: 99%

Absence of effects of predator control on nesting success of Northern Lapwings Vanellus vanellus: implications for conservation

Bodey

McDonald

Sheldon

et al. 2011

Ibis

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The control of generalist predator populations is increasingly adopted as a management tool to combat declines in ground‐nesting bird populations. However, compensatory predation by uncontrolled species frequently occurs, so determining the relative impacts of different predatory species, and hence the relative benefits of their control, can be difficult. Islands, with their reduced faunas, provide natural experimental units for investigating specific predator–prey interactions in detail. We studied Northern Lapwing Vanellus vanellus breeding success on an island where feral Ferrets Mustela furo and Hooded Crows Corvus cornix were subjected to trial control regimes over 2 years. In both years, Lapwing hatching success was >80%, with neither Ferret nor Crow control selected as important predictors. Fledging rates in both years were 0.7 young per pair, despite highly effective predator removal, although Crow control potentially resulted in compensatory predation by Common Ravens C. corax. Neither mustelid nor corvid control produced significant immediate benefits for Lapwings. This suggests that mesopredator release of mustelids in mainland situations is unlikely to be a consistent threat to Lapwing, and provides further evidence that declines in this species are unlikely to be tackled successfully through predator management alone.

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Removing American crows and duck nesting success

Cited by 24 publications

References 20 publications

Bird demographic responses to predator removal programs

Bird demographic responses to predator removal programs

The Relative Impacts of Nest Predation and Brood Parasitism on Seasonal Fecundity in Songbirds

Absence of effects of predator control on nesting success of Northern Lapwings Vanellus vanellus: implications for conservation

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