Identification of land predators of African Penguins Spheniscus demersus through post-mortem examination

Abstract

The African Penguin Spheniscus demersus is an endangered seabird endemic to southern Africa, and killing sprees by terrestrial predators have been one of the main threats for its mainland colonies. The methods employed to manage predators may differ depending on the species involved, therefore the implementation of strategies to limit the impacts of predation relies on the correct identification of the culprit predator. We report and quantify the lesions seen in African Penguins killed by four species of terrestrial predators: Caracal Caracal caracal (52 kills), Leopard Panthera pardus (27 kills), Domestic Dog Canis lupus familiaris (10 kills), and Cape Grey Mongoose Galerella pulverulenta (4 kills). We discuss patterns of necropsy findings that can be used to identify the predator species involved. Traditional forensic methods are useful tools to direct species-specific management actions for the conservation of the African Penguin and other seabirds so that effective mitigating measures can be deployed quickly to prevent further losses. It should be borne in mind, however, that the age, size and previous hunting experience of the predator are likely to influence the pattern of lesions that will be observed, and not all carcasses will have hallmark lesions or recognisable bite marks.

Evaluating risks to seabirds on the urban–coastal interface: Modelling dog attacks on little penguin populations in Tasmania

“…given that the available little penguin mortality data indicated that dog attacks were largely on adults and not juveniles, as other studies have found (Vanstreels et al, 2019).…”

“…Based on the available mortality data, dog attacks were assumed to occur mainly on penguins aged 2–4+ years old (i.e., $$$ {a}_c $$$ = 2, 3, 4). Predation on juvenile penguins was not included given that the available little penguin mortality data indicated that dog attacks were largely on adults and not juveniles, as other studies have found (Vanstreels et al, 2019).…”

“…Dog attacks on penguins are not confined to Tasmania and have been reported elsewhere, for example: on little penguins in New South Wales (Bourne & Klomp, 2004) and Victoria, Australia (Dann, 1991; Norman et al, 2017); little penguins and yellow‐eyed penguins ( Megadyptes antipodes ) in New Zealand (Hocken, 2000, 2005); Magellanic penguins ( Spheniscus magellanicus ) on islands off Patagonia (Morgenthaler et al, 2022); Galápagos penguins ( Spheniscus mendiculus ) on the Galápagos Islands (Barnett, 1986); and African penguins ( Spheniscus demersus ) in South Africa (Vanstreels et al, 2019). Whereas some of these attacks occur from roaming or feral dogs (e.g., Barnett, 1986; Barnett & Rudd, 1983), many occur due to unrestrained dogs—that is, pet dogs that have escaped or that are off lead with their owners (E. J. Woehler, personal communication; Kalmari, 2014), highlighting this as an ongoing and widespread management issue (Holderness‐Roddam & McQuillan, 2014).…”

“…Anecdotal reports suggest that most dog attacks in Tasmania occur on nesting adults when coming ashore to breed (P. F. Marker & E. J. Woehler, unpublished data). Dog attacks on other species of penguins, for example, S. demersus , also occur mostly on adults (Vanstreels et al, 2019). Given that seabird populations are more sensitive to the loss of adults than to the loss of chicks or eggs (Cuthbert et al, 2001; Cuthbert & Davis, 2002; Gownaris & Boersma, 2019; Hamilton & Moller, 1995; Lewison et al, 2012), there is concern regarding the viability of little penguin populations where they are exposed to additional predation from introduced predators such as dogs, frequently around the Tasmanian coastline.…”

Waterbirds: Birds of a feather flock together

“…The articles in this special issue are grouped largely into those focused on waterbirds of inland aquatic environments (de Souza et al 2019;Gula et al 2019;D'Urban Jackson et al 2019;Lee et al 2019;Neb et al 2019) and those focused on waterbirds in coastal and marine environments (Brown et al 2019;Dyer et al 2019;Sherley et al 2019;Tree et al 2019;Vanstreels et al 2019). Among the studies concentrating on inland waterbirds is one of the first attempts to quantify the long-suspected hybridisation between invasive Mallard Duck Anas platyrhynchos and native Yellow-billed Duck A. undulata in South Africa (de Souza et al 2019).…”