Travel far, breed abundantly and die young... Although it may sound like a hedonistic and rock-n-roll lifestyle, a new international study has revealed that this is how short-eared owls live

This highlights the need to plan conservation measures for this species on scales larger than previously considered

Travel far, breed abundantly and die young... Although it may sound like a hedonistic and rock-n-roll lifestyle, a new international study has revealed that this is how short-eared owls live. This highlights the need to plan conservation measures for this species on scales larger than previously considered.

The results show unexpectedly long-distance movements in the individuals tracked, with some of the marked birds traveling widely throughout Europe and North Africa. Some individuals were tracked during nesting over two seasons, and distances between nest sites used by the same individuals in consecutive years ranged from 41 to 4,216 km. According to the researchers, these represent some of the longest known distances between nest sites of any bird. Incredibly, a female marked at her nest in Scotland bred twice in the same year, once in Scotland and once in Norway.

These surprising movements seem to be due to the need to find places with sufficient prey to raise large broods. The abundance of short-eared owls' favourite prey, voles, can vary, both in time and space, making these rodents an unpredictable food resource. Although short-eared owls can change prey when voles are not available, their most common response is to move to other areas, resulting in irruptive or nomadic movements, although this has consequences in terms of survival: less than half of the adult individuals survive from one year to the next.

The types of movements recorded in this study, as well as their scale, show that there are no separate populations of Short-eared Owls across Europe. Instead, there is a single, potentially integrated population across most of the species' range. This new knowledge has significant implications for attempts to protect and conserve the short-eared owl, as it underlines the need to collect information on its populations at sufficiently large and/or long-term geographic scales and highlights the need to plan conservation measures for this species at larger scales than previously considered.

Reference:

• Calladine, J., Hallgrimsson, G. T., Morrison, N., Southall, C., Gunnarsson, H., Jubete, F., Sergio, F., Mougeot, F. 2024. Remote tracking unveils intercontinental movements of nomadic Short-eared Owls (Asio flammeus) with implications for resource tracking by irruptive specialist predators. Ibis (2024).