Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The European population is estimated at 227,000-381,000 pairs, which equates to 454,000-762,000 mature individuals (BirdLife International 2015). Europe forms approximately 57% of the global range, so a very preliminary estimate of the global population size is 796,000-1,337,000 mature individuals, although further validation of this estimate is needed. It is placed in the band 790,000-1,400,000 mature individuals.
The population is suspected to be in decline owing to ongoing habitat destruction. In Europe, the population size trend is unknown (BirdLife International 2015).
Declines in this species are most likely down to habitat changes and a reduction in insect populations (Holt et al. 1999), probably from the use of pesticides (König 2008). The spread of large-scale farming, modernisation of agricultural methods and the reduction in the number of hollow trees may have driven its extirpation from areas in France and Spain (Holt et al. 1999, König 2008). Urban developments may also lead to a loss of habitat (Martínez et al. 2007). In Switzerland, suitable habitat has been fragmented by spread of viniculture and agricultural intensification (Holt et al. 1999) and land abandonment leading to loss of grassland habitats favoured by the species is also a threat (Sergio et al. 2009). In Israel pesticide use reduced the population however increases have occurred since the 1970s (Holt et al. 1999). Locally, increases in predator populations, such as Tawny Owls (Strix aluco) may lead to decreases in this species (König 2008). Hunting, along migration routes in Italy and Malta, are also thought to impact the species (Tucker and Heath 1994).
Text account compilers
Ekstrom, J., Butchart, S., Elliott, N., Ashpole, J
BirdLife International (2019) Species factsheet: Otus scops. Downloaded from http://www.birdlife.org on 10/12/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 10/12/2019.