Behavioral traits vary with intrinsic factors and impact local survival in Song Sparrows (Melospiza melodia)/Caracteristicas conductuales varian segun factores intrinsecos e impactan sobrevivencia local en el gorrion Melospiza melodia

Food acquisition is critical for individual fitness. Recent work has highlighted the importance of behavioral traits, such as boldness, for explaining variation in foraging abilities within populations. Greater flexibility in these behavioral traits might help populations persist in the face of environmental change; this may be particularly important for small populations that are more susceptible to local extirpation. We performed a winter-feeding experiment in an extensively studied island population of Song Sparrows (Melospiza melodia) to examine if intrinsic factors (age, sex, and inbreeding) explain variation in behavioral traits (neophobia, boldness toward predators, boldness toward competitors, and aggression) and how behavioral traits influence the probability of local survival for adults and of no dispersal and survival for juveniles. Our results showed that adults were less neophobic and bolder toward competitors than juveniles. This suggests that juvenile Song Sparrows might be more vulnerable to environmental changes than adults and may help explain why juvenile survival has been more strongly impacted by a new competitor on the island. Females were less neophobic than males, indicating that the sexes vary in their behaviors associated with resource acquisition, potentially due to constraints associated with reproduction in females. We found that the individual inbreeding coefficient did not appear to influence any of the behavioral traits examined here. Lastly, more neophobic adults were found to be more likely to survive to hold a territory the following breeding season, demonstrating the consequences of behavior on future fitness. These findings highlight that behavioral traits impact resource acquisition and fitness, and, thus, variation in these behaviors may play a critical role in understanding and predicting how populations respond to environmental change. Received 25 August 2021. Accepted 26 February 2022. Key words: age, aggression, boldness, inbreeding level, neophobia, sex. La adquisicion de alimento es critica para la sobrevivencia individual. Trabajos recientes han destacado la importancia de caracteristicas conductuales, como la osadia, para explicar la variacion en capacidades de forrajeo al interior de poblaciones. Una mayor flexibilidad en caracteristicas conductuales podria ayudar a las poblaciones a persistir de cara al cambio ambiental y esto podria ser particularmente importante para poblaciones pequehas que son mas susceptibles a extinciones locales. Llevamos a cabo un experimento de alimcntacion invernal en una poblacion del gorrion Melospiza melodia que ha sido extensamente estudiada para examinar si factores intrinsecos (edad. sexo y endogamia) explican la variacion en las caracteristicas conductuales (neofobia, osadia ante depredadores, osadia ante competidores y agresion) y como las caracteristicas conductuales influencian la probabilidad de sobrevivencia local para los adultos, y la nodispersion y sobrevivencia para juveniles. Nuestros resultados muestran que los adultos fueron menos neofobicos y mas osados hacia competidores que los juveniles. Esto sugiere que los gorriones juveniles podrian ser mas vulnerables a cambios ambientales que los adultos y csto podria ayudar a explicar por que la sobrevivencia de los juveniles ha estado mas fuertemente impactada ante un nuevo competidor en la isla. Las hembras fueron menos neofobicas que los machos, indicando que los sexos varian en comportamientos asociados con adquisicion de rccursos. potencialmente debido a limitacioncs asociadas con la reproduccion en las hembras. Encontramos que el coeficiente de endogamia individual no parece influenciar ninguna de las caracteristicas conductuales que examinamos aqui. Finalmente. los adultos mas neofobicos fueron mas proclives a sobrevivir y asegurar un territorio en la siguicntc temporada reproductiva. demostrando las consecuencias del comportamiento en la sobrevivencia futura. Estos hallazgos destacan que las caracteristicas conductuales impactan la adquisicion de recursos y, por ello, la variacion en estas conductas podria jugar un papel critico en nuestro entendimiento y capacidad de predecir como responden las poblaciones al cambio ambiental. Palabras clave: agresion. edad, neofobia. nivel de endogamia, osadia, sexo.
An individual's ability to obtain food resources is critical for individual fitness and can have cascading effects on a population's stability and ability to withstand changing environments (Arcese and Smith [...]