Exploring object neophobia in wild nesting House Wrens

CARRO, MARIANA E; FERNÁNDEZ GUSTAVO J.

Conferencia; Northeast Natural History Conference; 2021

Neophobia is an aversivebehavior towards novel objects or places. Many animals show some degree ofaversion to novelty, and neophobia can shape their responses to theenvironment. Here, we examine the individual variation in the response ofnesting Troglodytes aedon bonariae (House Wrens) to a novel object, and assess the relationship ofthese responses with the individual aggressiveness and the risk-takingresponses when there is a potential threat near the nest. Also, we evaluate theeffect of age, body size and condition on the responses of individuals. Thestudy was conducted in General Lavalle, Buenos Aires province, Argentina,during the 2014 and 2015 breeding seasons (September-January). A total of 17breeding pairs were tested. The individuals used in these experiments werecaptured, banded (those that were not previously marked), weighed and theirtarsus was measured. We used playback experiments to characterize theaggressive response of males and exposed the nest to a threat during egg-layingto assess the aggressive response of females. During the nestling rearingperiod, when nestlings were 10-days old, we placed a piece of white paperaround the entrance of the nest. We measured the latency to enter of both malesand females as a measure of avoidance to the novel object. The response to apotential risk near the nest was measured as the latency to enter the nest ofmales and females when an observer was positioned 10 m from the nest. Males andfemales differed in their response to the novel object. The response of maleswas positively related to their response to a threat to the nest. In addition,individuals with larger body sizes have shorter latency to enter the nest inpresence of the novel object. The response of females was mostly explained bythe age of the individuals, as older females are more likely to explore thenovel object. The results show that neophobia seems to respond not only toindividual characteristics but may also be influenced by life historystrategies, responding to the relative costs and benefits for each sex.