Ecology: Drought has life-long consequences for red kites

Red kites (Milvus milvus) born during a period of drought are disadvantaged throughout life, finds a study of a red kite population in Spain published in Nature Communications. As red kites can live up to 30 years, the findings suggest that extreme climate events can have a long lasting impact on red kite populations, which are declining in some regions.

Climate change is increasing the frequency of extreme events, which have an impact on wildlife communities. However, the long-term effects of extreme climate events in early life are largely overlooked in forecasts of climate change impacts. Stressful conditions during early development can have lasting consequences on an individual’s ability to survive and reproduce, and an individual’s resilience to subsequent stressful periods.

Fabrizio Sergio and colleagues investigated the effects of drought in a long-term study population of red kites in Doñana National Park, Spain. The authors found that drought reduced both prey availability and the amount of food provided to chicks by parents, leading to leaner chicks and fewer chicks reaching adulthood in drought years. They also indicate that experiencing drought as chicks did not provide an advantage in surviving subsequent droughts. Even if chicks survived the drought, the authors suggest their survival chances in later years was lower than that of red kites born in years with typical precipitation. They included the long-term effects of drought in population projection models and found that they led to a 40% decline in forecasted population size and a 21% shortening of the time to extinction.

Sergio and co-authors conclude that increasingly frequent extreme climate events may be having greater consequences and eroding populations more quickly than is currently recognized.