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Biological Invasions

, Volume 13, Issue 6, pp 1447–1455 | Cite as

Toad’s tongue for breakfast: exploitation of a novel prey type, the invasive cane toad, by scavenging raptors in tropical Australia

  • Christa BeckmannEmail author
  • Richard Shine
Original Paper

Abstract

Although interest in the ecological impacts of invasive species has largely focused on negative effects, some native taxa may benefit from invader arrival. In tropical Australia, invasive cane toads (Bufo marinus) have fatally poisoned many native predators (e.g., marsupials, crocodiles, lizards) that attempt to ingest the toxic anurans, but birds appear to be more resistant to toad toxins. We quantified offtake of dead (road-killed) cane toads by raptors (black kites (Milvus migrans) and whistling kites (Haliastur sphenurus)) at a site near Darwin, in the Australian wet-dry tropics. Raptors readily took dead toads, especially small ones, although native frogs were preferred to toads if available. More carcasses were removed in the dry season than the wet season, perhaps reflecting seasonal availability of alternative prey. Raptors appeared to recognize and avoid bufotoxins, and typically removed and consumed only the toads’ tongues (thereby minimizing toxin uptake). The invasion of cane toads thus constitutes a novel prey type for scavenging raptors, rather than (as is the case for many other native predators) a threat to population viability.

Keywords

Bufotoxin Chaunus marinus Frog Invasive species Rhinella marina Road-kill 

Notes

Acknowledgments

We thank P. Biro, G. Brown, M. Crossland, M. Greenlees and L. Pizzatto for assistance with collecting toad and frog carcasses. All procedures were approved by the University of Sydney Animal Ethics Committee, and conducted under permits from the Northern Territory Parks and Wildlife Service. This study was funded by the Australian Research Council.

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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.School of Biological Sciences A08University of SydneySydneyAustralia

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