The Short-eared Owl is Amber listed in the Birds of Conservation Concern because it is a Species of European Conservation Concern [British Birds 102; 296-341].
The estimate of the current British breeding population is derived from the 1988-91 Breeding Atlas, (Gibbons et al 1993), with figures of between 1000 and 3500 pairs. These were repeated in Baker et al, (2006) [British Birds 99: 25-44]. Gibbons et al suggested that the lower limit might apply. There are no recent estimates but the Rare Breeding Birds Panel (RBBP) has now adopted the Short-eared Owl for inclusion in its future reports because of the uncertainty over the size of the population and concern that is may have fallen below a threshold of 1000 pairs.[British Birds 104: 476-537]
Short-eared Owls breed throughout the uplands of the UK on heather moor, white moor, young conifer plantations and rough unimproved pasture. Locally, coastal marsh habitats are also used. Breeding population numbers have always been modest and prone to marked fluctuations in line with vole numbers.
The species is recognised as being difficult to survey. The annual monitoring conducted by field-workers for breeding Merlin often provides the opportunity to confirm breeding of SEO. This does create a bias towards heather moorland habitat and pairs on white moor, adjoining rough pasture and new afforestation may go under-recorded, especially if they breed in early spring
The main prey consists of rodents and small birds with the Short-tailed Field Vole being their primary food source. Breeding success invariably fluctuates with vole abundance. Their failure to fully exploit suitable habitat and the current suggestions of decline are not fully understood. Prey abundance is likely to be the dominant factor but winter survival and even persecution may play a part
Most raptor study groups monitor SEO in tandem with other survey work but the general trend has been towards the discovery of fewer displaying or breeding pairs despite many experienced observers providing near-constant effort monitoring year-to-year. That birds are now absent or scarce from several traditional areas of apparently still suitable habitat is of considerable concern.
The species is clearly a strong candidate for a more co-ordinated approach to monitoring across our region, even with the known problems of having an appropriate survey methodology.
The RBBP adoption of the Short-eared Owl is welcomed and will hopefully provide a stimulus for more detailed data collection. NERF would also recommend that consideration be given to adding the species to the Schedule 1 Annex .