Avian responses to an extreme weather event: The case of the 'Filomena' snowstorm in Madrid (central Spain)

Cold spells and severe weather may have detrimental effects in wild birds, but owing to the stochastic nature of these events, it is not always possible to measure their impacts. In January 2021, a strong snowstorm known as 'Filomena' affected Spain, mainly the region of Madrid (Central Spain), which was fully covered with snow and suffered freezing temperatures for a fortnight. Using bird surveys conducted in the winter-spring of 2020 and 2021 (before and after Filomena) at same locations, we addressed the possible impact of the cold spell in three widespread gamebirds: Wood Pigeon (Columba palumbus), Eurasian Magpie (Pica pica) and Red-legged Partridge (Alectoris rufa). No significant abundance differences were found between years for none of the species and hunting pressure was only significantly reduced for Partridges, hence this species may have been negatively affected by Filomena. Results suggest that in response to Filomena, Pigeons conducted partial migration in search of better conditions, while Magpies aggregated in certain areas of Madrid and Partridges endured the harsh conditions within their home ranges. Our results highlight the importance to alleviate negative impacts of extreme weather events in wild birds through management actions, especially for sedentary species.