Predator‐avoidance behaviour in a nocturnal petrel exposed to a novel predator

Abstract

Many species of bird recognize acoustic and visual cues given by their predators and have complex defence adaptations to reduce predation risk. Recognition of threats posed by specific predators and specialized anti-predation behaviours are common. In this study we investigated predator recognition and anti-predation behaviours in a pelagic seabird, Leach's Storm-petrel Oceanodroma leucorhoa, at a site where predation risk from Great Skuas Stercorarius skua is exceptionally high. Leach's Storm-petrels breed in burrows and come on land only at night. Counter-predator adaptations were investigated correlatively in relation to changing natural light levels at night, and experimentally in relation to nocturnal visual and acoustic signals from Great Skuas. Colony attendance by Leach's Storm-petrels was attuned to changes in light conditions at night and was highest when nights were darkest. This behaviour is likely to reduce predation risk on land; however, specific recognition of Great Skuas and specialized defence behaviours were not found. Leach's Storm-petrels, in particular apparently non-breeding individuals, were entirely naïve to the threat posed by Great Skuas and were captured easily in a variety of different ways, on the ground and in the air. Lack of specialized behavioural adaptations in Leach's Storm-petrels against Great Skuas may be because spatial overlap of breeding distributions of these species appears to be a rare and recent phenomenon.

Temporal and environmental influences on the vocal behaviour of a nocturnal bird

“…This apparent response to anthropogenic light levels is in contrast to the lack of significant moonlight effect. Moon effects can be masked by cloud cover (Miles et al ), but our results showed no association between call rates and the lunar cycle even in clear conditions. The influence of moon on calling levels is uncertain in brown kiwi, with several reports that they are less vocal in bright moon periods (Clark , Colbourne and Kleinpaste ), but others finding no effect (Pierce and Westbrooke ).…”

Testing the use of infra‐red video cameras to census a nocturnal burrow‐nesting seabird, the European Storm PetrelHydrobates pelagicus

“…Poor quality was mainly due to precipitation and low light levels on cloudy moonless nights. Fewer activity events were detected when image quality was poor, even though Storm Petrels may favour dark nights for entering or leaving burrows (Miles et al 2013). Infra-red filming may therefore greatly underestimate activity levels on the darkest nights.…”

Challenges of Learning to Escape Evolutionary Traps

“…• Avoid or ignore beneficial options (e.g., avoid high quality restored habitats, Hale and Swearer, 2017; or novel foods, Pearse et al, 2013); • Approach or fail to avoid stimuli with negative fitness outcomes (e.g., consume novel toxic foods, Crossland et al, 2008; oviposit on invasive plants, Keeler and Chew, 2008; or allow close contact with novel predators, Miles et al, 2013;or pathogens, Bouwman and Hawley, 2010); • Fail to ignore neutral stimuli (e.g., avoid or be stressed by passing tourists unnecessarily, Ellenberg et al, 2007).…”

“…The errors that cause traps can go "both ways." They include the underuse of good habitat or resources (Gilroy and Sutherland, 2007), and the overuse of poor habitat (Robertson et al, 2013) or toxic "foods" (e.g., cane toads, Shine, 2010); as well as the underavoidance of novel predators Miles et al, 2013), and the over-avoidance of situations and habitats that are safe, but appear dangerous (Hale and Swearer, 2017;Trimmer et al, 2017).…”