Carrion subsidies provided by fishermen increase predation of beach‐nesting bird nests by facultative scavengers. (15th May 2014)

• Record Type: Journal Article
• Authors: Rees, J. D.; Webb, J. K.; Crowther, M. S.; Letnic, M.
• Is Part Of: Animal conservation. Volume 18:Number 1(2015:Feb.)
• Page Start: 44
• Page End: 49
• Publication Date: 2014-05-15
• Subjects: Conservation biology -- Periodicals; Wildlife conservation -- Periodicals; Conservation de la biodiversité; Conservation de la faune; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 333.95416
• DOI: 10.1111/acv.12133
• Languages: English
• ISSNs: 1367-9430

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Many predators are also scavengers that feed on carrion and human refuse. Therefore, the availability of carrion can elevate the abundance or activity of facultative scavengers, amplifying predation pressure on prey. On Australian beaches, fishermen often discard fish carcasses that could attract facultative scavengers, both native, such as Australian ravens <italic>C</italic><italic>orvus coronoides</italic>, and invasive, such as European red foxes <italic>V</italic><italic>ulpes vulpes</italic>, and result in elevated rates of predation on wildlife. We tested whether the presence of fish carcasses increased the risk of depredation for nearby nests of beach‐nesting birds by deploying artificial nests in 12 subsidized and 12 control patches, spaced 1 km apart, on a beach. We placed a fish carcass in each subsidized patch, but not at control patches. In each patch, we placed two artificial nests, which resembled red‐capped plover <italic>C</italic><italic>haradrius ruficapillus</italic> nests, 80 m apart and 40 m from carcasses at subsidized patches. Nest predators were identified from tracks and predator activity near subsidized and control nests was measured by counting tracks crossing a straight transect (220 m). The activity of a native predator, the Australian raven, was 17 times higher near (<80 m) nests with fish carcasses than nests without carcasses. After 72 h, 96% of nests near carcasses were depredated compared with 30% of nests without carcasses. Ravens were identified as the culprit for 80% of depredated nests. Although other predators were present in the study area, they did not depredate artificial nests in this experiment. Previous studies have highlighted the effects of permanent and/or large‐scale food resources on scavenger abundance and impact. A key management implication of our study is that even small, sparsely distributed, temporally irregular food subsidies, provided by humans, can elevate the activity and predatory impacts of facultative scavengers.</p> </abstract>