Australasian Swamphen Porphyrio Melanotus Killing and Processing a Cane Toad Rhinella Marinus

Australian Field Ornithology 2018, 35, 72–74 http://dx.doi.org/10.20938/afo35072074 Australasian Swamphen Porphyrio melanotus killing and processing a Cane Toad Rhinella marinus Katherine J. Wilk P.O. Box 1961, Kingscliff NSW 2487, Australia Email: [email protected] Abstract. An Australasian Swamphen Porphyrio melanotus was seen and photographed catching and killing a Cane Toad Rhinella marinus, extracting the internal organs through the toad’s mouth, holding the toad’s body underwater, and presenting the kill to well-grown chicks at Canoe Point, central Queensland, on 28 December 2015. The observations suggest careful behaviour to avoid ingesting toxins. Comparable behaviours have been reported for other bird species, but this seems to be the first documented case for the Australasian Swamphen, and the first report of viscera being extracted through the toad’s mouth. Introduction Observations The Cane Toad Rhinella marinus was first introduced into On 28 December 2015 in mid afternoon, I observed an north Queensland in 1935 (Anstis 2013), and now occurs adult Australasian Swamphen chasing a large Cane Toad from the far north-eastern Kimberley in Western Australia, (body length estimated as ~15 cm) along the shoreline of across the coastal and sub-coastal parts of the Northern a small artificial lake at Canoe Point Environment Park, Canoe Point (23°57′S, 151°22′E), Tannum Sands, central Territory and the Gulf of Carpentaria, and down the eastern Queensland. Initially, the Swamphen was moving slowly coast of Queensland into northern New South Wales as along the shoreline following the toad, which was not far south as Port Macquarie (Anstis 2013). It is abundant vigorously trying to escape. It is possible that the toad was along the central Queensland coastal plain (pers. obs.). already lethargic from being harassed or already wounded Cane Toads secrete liquid containing poisonous bufotoxins by the Swamphen. from large parotoid glands on the shoulders, and this can be fatal to native carnivores that eat the toads (Beckman The Australasian Swamphen then held the Cane Toad in & Shine 2011). a foot grasp around the body and attacked it with its beak through the toad’s mouth (Figure 1). It was not observed The Australasian Swamphen Porphyrio melanotus pecking at the toad’s body or legs, although at one stage it (formerly known as Purple Swamphen Porphyrio held one of the toad’s front legs to move the toad back to porphyrio) is distributed across all states and territories the shoreline. The toad had white liquid (bufotoxin) oozing of Australia (Marchant & Higgins 1993; Menkhorst et al. from its parotoid glands (Figure 2). I did not observe the 2017). It is primarily herbivorous, but frogs, small fish, Swamphen holding the toad near these glands nor pecking at this area. Several times, it took the toad into the lake crustaceans, molluscs, insects, young birds, lizards and and, with its beak and feet, held the toad under water for small mammals have also been recorded as food items a short period. I could not determine if this was to wash (Marchant & Higgins 1993). It is not known if it suffered the bufotoxin from the toad or to wash the poison from its a decline following the introduction and spread of the beak. Once the toad was dead, the Swamphen continued Cane Toad across eastern and northern Australia. Several to probe the toad’s mouth. It appeared to extract the studies report that birds are less susceptible than other intestine and other viscera from the toad via the mouth taxa to the Cane Toad’s poison (Beckman & Shine 2011; opening, but I could not determine if it consumed any of Beckman et al. 2011). Beckman & Shine (2011) reported the extracted organs. Eventually a long section of intestine hung from the toad’s mouth. The Swamphen then waded that Whistling Kites Haliastur sphenurus and Black Kites into the lake towards a central island and, when it was too Milvus migrans in tropical Australia readily took dead Cane deep to wade, it swam, all the time holding with its beak Toads and typically consumed the tongues. Ringma (2013) the toad’s extruding intestine as high as possible out of the reported several observations of a specifically identifiable water while the toad’s body trailed in the water (Figure 3). Laughing Kookaburra Dacelo novaeguineae ingesting Before reaching the island three well-grown chicks came Cane Toads over several days. out to join the Swamphen carrying the dead toad. It was always the same Swamphen attacking the toad, although This note describes the capture and killing of a large another adult came to inspect it (Figures 4–5), with the Cane Toad by an Australasian Swamphen and the first Swamphen apparently not at all disturbed. These two subsequent extraction of the intestine and other viscera Swamphens were seen to exchange a food item (possibly from the Cane Toad. the toad’s intestine). I did not at any stage witness the Australasian Swamphen kills and processes Cane Toad 73 Figure 1. Australasian Swamphen attacking a Cane Toad Figure 2. Note the white bufotoxins visible on the parotoid via its mouth. Inset shows close-up. Photo: Judith Boland glands and along the back of the Cane Toad. Photo: Katherine J. Wilk Figure 3. Australasian Swamphen carrying Cane Toad Figure 4. A second Australasian Swamphen inspects the across the water. Extracted intestine is clearly visible in the dead Cane Toad. Photo: Katherine J. Wilk Swamphen’s beak. Photo: Katherine J. Wilk Figure 5. The second Australasian Swamphen inspects Figure 6. Adult Australasian Swamphens with the dead the Cane Toad. Note the bufotoxins oozing from the toad. Cane Toad, and two of the chicks that came out from the Photo: Katherine J. Wilk island. Photo: Katherine J. Wilk 74 Australian Field Ornithology K.J. Wilk Swamphen trying to clean its beak or wipe off any poison. Acknowledgements The family group viewed the toad on the sand (Figure 6), I thank David Charley for preparing a draft of this short note and and then the adult that had killed the toad carried it into for undertaking a search for existing published observations. I the long grass in the centre of the island (out of view). also thank Linda Brannian for providing references and helpful The family group followed, but I did not witness the chicks comments on a draft and Judith Boland for providing Figure 1. I or adults consuming the toad. This observation took c. thank referees John Seymour and Martin O’Brien for their helpful 6 minutes in total, although I am not sure how long the comments. Swamphen had been attacking the toad before I noticed. It was not possible to see which parts of the toad were consumed by the adults or chicks, or to make follow-up References observations to monitor their health and survival. Anstis, M. (2013). Tadpoles and Frogs of Australia. New Holland Publishers, Sydney. Barker, R.D. & Vestjens, W.J.M. (1989). The Food of Australian Discussion Birds, Volume 1: Non-passerines. CSIRO Division of Wildlife & Ecology, Canberra. Beckman, C. & Shine, R. (2011). Toad’s tongue for breakfast: Several native Australian birds have been documented as Exploitation of a novel prey type, the invasive cane toad, by preying on Cane Toads. These include Bush Stone-curlew scavenging raptors in tropical Australia. Biological Invasions Burhinus grallarius (Barker & Vestjens 1989), Masked 13, 1447–1455. Lapwing Vanellus miles (Marchant & Higgins 1993), Beckman, C., Crossland, M.R. & Shine, R. (2011). Responses of Australian White Ibis Threskiornis moluccus (McCann 1986 Australian wading birds to a novel toxic prey type, the invasive in Donato & Potts 2004), Brahminy Kite Haliastur indus cane toad Rhinella marina. Biological Invasions 13, 2925–2934. (Wren 2000), Black Kite (Forsyth 2000), Torresian Crow Donato, D.B. & Potts, R.T. (2004). Culturally transmitted predation and consumption techniques by Torresian Crows Corvus orru Corvus orru (Donato & Potts 2004) and Australian Raven on Cane Toads Bufo marinus. Australian Field Ornithology 21, C. coronoides (Donato & Potts 2004). At least four of these 125–126. species—Torresian Crow (D. Charley pers. comm. 2016), Forsyth, R. (2000). Black Kites and Cane Toads in Queensland. Australian White Ibis and Brahminy and Black Kites—have Boobook 20, 17. been observed to predate and feed on a Cane Toad by Marchant, S. & Higgins, P.J. (Eds) (1993). Handbook of Australian, rolling it onto its back to expose the soft underbelly, then New Zealand & Antarctic Birds, Volume 2: Raptors to Lapwings. exposing and consuming the intestine. They have also Oxford University Press, Melbourne. been observed feeding on the fleshy thighs (Donato & Potts McCann, J. (1986). Lakefield National Park: For the birds. Geo , 65–69. 2004). There appear to be no documented observations of 1 Menkhorst, P., Rogers, D., Clarke, R., Davies, J., Marsack, P. Australasian Swamphens feeding on Cane Toads and no & Franklin, K. (2017). The Australian Bird Guide. CSIRO reports of this species or other birds killing Cane Toads Publishing, Melbourne. and then extracting the viscera through the mouth opening. Ringma, J. (2013). Survival of a Laughing Kookaburra (Dacelo The presentation of the carcass to the young birds and the novaeguinea) after the predation of a Cane toad (Rhinella apparent watching of the predation technique suggest the marina). Memoirs of the Queensland Museum: Nature 56 possibility that the adult was educating the chicks, and 589–591. possibly the other adult, in the killing process and method Wren, J. (2000). Brahminy Kites and Cane Toads (Queensland). of extracting the edible internal organs from this poisonous Boobook 20, 19. species. It also suggests a deliberate behaviour to avoid eating poisonous parts of the prey. Received 4 October 2017, accepted 14 February 2018, published online 7 June 2018.

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