Anti‐predator behaviour in a procellariid seabird: Wedge‐tailed shearwaters do not respond to the odour of introduced ship rats

Abstract

International audienceSeabirds are particularly vulnerable to introduced alien mammalian predators, especially invasive rats, which are the main contributors to seabird extinction and endangerment in many places worldwide. However, this appears context-dependent because, paradoxically, cases of apparent long-term coexistence between rats and some species of seabird have been reported for centuries, in various locations. Among seabirds, procellariiforms are known to have developed a range of olfactory-driven behaviours, such as partner recognition and homing. Olfaction could be an effective means of recognizing and thereafter avoiding invasive predators. However, the role of olfaction in predation risk assessment has not yet been examined in any procellariiform. Here, we investigated, through a Y-maze experiment, whether the wedge-tailed shearwater (Puffinus pacificus) avoided the odour of one of the most damaging alien predators on islands, the ship rat (Rattus rattus). The experiment was conducted in different ecological contexts on three neighbouring islets off New Caledonia having different communities of invasive rats. Contrary to our expectations, the wedge-tailed shearwater either did not detect or did not avoid the odour of the ship rat, despite about 175 years of coexistence between rats and shearwaters in New Caledonia. These findings highlight the need for further investigations (across species, across sites) into the factors underpinning the paradox between high vulnerability and the surprising long-term coexistence between procellariid seabirds and alien invasive rats

Wild great and blue tits do not avoid chemical cues of predators when selecting cavities for roosting

“…Moreover, male house sparrows ( Passer domesticus ) avoided the scent of a potential predator or competitor ( Mus musculus domesticus ) when inspecting nest-boxes for roosting [ 31 ]. However, in other cases, the presence of predator scent did not affect nesting preferences ( Sialia sialis [ 32 ]) or parental behaviour ( Troglodytes aedon [ 33 ]); or nesting was not avoided ( Puffinus pacificus [ 34 ]).…”

Disentangling the processes driving tree community assembly in a tropical biodiversity hotspot (New Caledonia)

“…The New Caledonian biota exhibits a range of emblematic island attributes: for example, adaptive radiations (Barrabé et al., ; Pillon, Hopkins, Rigault, Jaffré, & Stacy, ), disharmony (Pillon et al., ) and ecological naïveté (Gérard, Jourdan, Millon, & Vidal, ). However, evidence for community‐level features typical to islands, including biota impoverishment or the vacancy of a portion of the environmental space, is lacking.…”

“…The New Caledonian biota exhibits a range of emblematic island attributes: for example, adaptive radiations (Barrabé et al, 2018;Pillon, Hopkins, Rigault, Jaffré, & Stacy, 2014), disharmony (Pillon et al, 2010) and ecological naïveté (Gérard, Jourdan, Millon, & Vidal, 2015). However, evidence for community-level features typical to F I G U R E 2 Variation in the accuracy of tree species assemblage predictions derived from four stacked species distribution models along an elevation gradient: red ='Environment', that is, accounting for environmental filtering only; blue = '+Dispersal', that is, accounting for environmental filtering and dispersal; green = '+Saturation', that is, accounting for environmental filtering and assemblage saturation; and black = 'All', that is, accounting for environmental filtering, dispersal and assemblage saturation.…”