A monogamous bird species in Seychelles shows higher divorce rates following periods of insufficient or excessive rainfall.
According to a new study published in the Journal of Animal Ecology, rainfall impacts the divorce rates of Seychelles warblers, a small bird species that only inhabits five islands in the African nation of Seychelles. This finding suggests that changing weather patterns due to climate change can significantly affect the reproductive processes of many animal species worldwide, as reported by Newsweek on November 26.
A pair of Seychelles warblers on Cousin Island. (Photo: Yasuyoshi Chiba/iStock)
In this new study, researchers analyzed the mating behavior of Seychelles warblers on Cousin Island over a 16-year period and compared it to weather patterns during the same timeframe. This species is monogamous, meaning a male and female form a long-lasting relationship, often spanning multiple mating seasons or even a lifetime.
Monogamy exists in about 90% of bird species, but sometimes relationships break down without one partner dying. This phenomenon is referred to as divorce. The research team noted that divorce is often linked to poor reproductive success. Approximately 92% of monogamous bird species have been recorded as experiencing divorce, with rates varying among species.
During the study period, the annual divorce rates among Seychelles warblers ranged from 1% to 16%. Notably, the researchers found a correlation between their divorce rates and rainfall levels. More instances of divorce occurred during years of low or unusually high rainfall, according to co-author Frigg Speelman, a behavioral ecology PhD candidate at Macquarie University.
This may stem from low rainfall leading to reduced food availability, while high rainfall can hinder the birds’ ability to maintain body temperature, as well as damage their habitats and nests. Additionally, there is a possibility that both high and low rainfall increase physiological stress levels in the birds, which is a critical factor in mate selection. The research team did not find a direct link between divorce rates and reproductive success, or the number of offspring produced, suggesting that other factors may also influence divorce rates.
In the context of rapid climate change, this new discovery is concerning for Seychelles warblers, which are already facing numerous conservation challenges, as well as for other bird species globally. “This new research not only enhances our understanding of animal behavior in the face of climate change but also provides valuable information that may aid conservation efforts for species vulnerable to the impacts of climate change,” Speelman stated.
