Risk‐taking behaviour relates to timing of breeding in a sub‐Antarctic rainforest bird

Abstract

Within‐population variation in timing of breeding may be linked to a trade‐off between the risks and benefits of breeding earlier. This trade‐off may be mediated by individual risk‐taking behaviour, but this needs to be assessed in detail in wild populations. Here, we recorded timing of breeding and risk‐taking behaviour during three consecutive breeding seasons in a resident population of Thorn‐tailed Rayadito Aphrastura spinicauda located in Navarino Island (55°S), southern Chile. Navarino is a high‐latitude, highly seasonal continental island in southern Chile where early breeding may be risky for rayaditos, given the presence of low temperatures, storms and relatively low food abundance during early spring. We used novel environment tests to assess exploratory behaviour, which in turn was used as a proxy of risk‐taking behaviour. In addition, we evaluated the potential consequences of timing of breeding and risk‐taking behaviour on three measures of reproductive success: clutch size, number of fledglings produced and body condition of the offspring. We found that risk‐prone individuals started breeding earlier than risk‐averse individuals but we did not find evidence for an effect of timing of breeding on any of the variables of seasonal breeding success. However, we observed that fast‐exploring females tended to lay smaller clutches. Measurements reflecting lifetime reproductive success may better reflect an effect of timing of breeding and risk‐taking behaviour, but this needs to be studied. Our results support the idea that risk‐taking behaviour is linked to early breeding in high‐latitude environments. We suggest that, despite the risks that low temperatures and snowstorms pose to breeding rayaditos during early spring, it is possible that early breeders increase the probability of occupying better nesting cavities and they may adjust the timing of breeding to match brood provisioning with peak resource abundance.

Antipredator benefits of heterospecific colonial breeding for a predominantly solitary bird

“…Rollers' risk-taking behaviour, both towards a novel object and a predator, was also influenced by laying date, with early breeders generally (but not always) performing better than late breeders. In birds, early breeders are often older or more experienced individuals, selecting higher quality breeding areas, having higher reproductive success, and being more risk prone (Verhulst & Nilsson 2008;Brommer et al 2014;Winkler 2016;Poblete et al 2021). Our data, from six consecutive breeding seasons, showed that early breeding rollers laid more eggs and had higher productivity (number of fledging chicks) than late breeders.…”

“…Year was not included in the model was there was no difference in roller's response between years (w74 = 597, P = 0.306). Laying date was used to control for individual traits/experience, under the assumption that early breeders are older, more experienced individuals and more risk prone (Verhulst & Nilsson 2008;Brommer et al 2014;Winkler 2016;Poblete et al 2021). A log-link was used as data had a right-skewed distribution.…”

Exposure to Sublethal Concentrations of Lead (Pb) Affects Ecologically Relevant Behaviors in House Sparrows (Passer domesticus)

“…3 ). Similar methods have been used to infer aspects of avian locomotory behavior such as exploration (McCowan et al 2015 ; Huang et al 2012 ), risk-taking (Pobleté et al 2021 ), and boldness (McCowan et al 2015 ). We performed each activity assay between 09:00 and 15:00 in a soundproof, indoor aviary (3L × 3W × 2.5H m).…”

Geographic variation in the altitudinal migration patterns, body size, oxidative status and exploratory behavior in a neotropical bird

“…To evaluate exploratory behavior, we conducted novel environmental tests shortly after capturing the birds, following the protocol described by Verbeek et al (1996). To this end, we used a field-portable aviary (270 cm long × 150 cm wide × 150 cm high) made of removable poles and semitransparent black cloth (see Poblete et al, 2018Poblete et al, , 2021Botero-delgadillo, Quirici, Poblete, Poulin, et al, 2020 for aviary details). The aviary had 14 possible perching locations, including perches and walls.…”

“…About 1 min before starting the trial, we removed this cloth, and the door of the acclimatization cage was opened for each subject who was free to explore. We used a digital camera (Sony DCR-68) for recording the behavior of each bird for 10 min (Botero-delgadillo et al, 2019;Poblete et al, 2018Poblete et al, , 2021.…”