Do weather conditions during the brood rearing period affect the survival of owl chicks on a subtropical island?

抄録

Suitable climatic conditions for the species are known to improve the breeding success of birds, and the ways in which climatic conditions affect bird breeding have been well studied in temperate and subarctic zones. However, hypotheses made from limited regional information may not be adaptable to other regions, and studies in other areas are needed. It is important to determine the impact of weather conditions on birds on isolated islands, because it is difficult for them to adjust their habitats in response to climate conditions. This study elucidated the effects of weather conditions on the breeding of Ryukyu Scops Owls Otus elegans on the subtropical Minami-daito Island, Japan. The study used data from 806 chicks over a six-year period from 2016 to 2021. We found that heavy rain caused increased chick mortality. Chicks weighed less and had shorter tarsi and wings when precipitation was higher. Structural equation analysis showed that high precipitation reduced chick weight and indirectly increased mortality. Heavy rains were thought to have restricted the foraging behaviour of the parents, resulting in a decrease in chick weight.