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). The population trend is suspected to be stable, and hence the species does not 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 20,000-41,700 pairs, which equates to 40,100-83,400 mature individuals (BirdLife International in prep.). Europe forms approximately 15% of the global range so a very preliminary estimate of the global population size is 267,000-556,000 mature individuals. Partners in Flight (2020) estimate the North American population at approximately 1,600,000 mature individuals, and the global population at 3,200,000 mature individuals. Given the wide range of the population estimates, the global population is placed in the band 250,000-3,200,000 mature individuals.
In North America, this species has undergone a large and statistically significant increase over the last five decades (on average 3.5% per year, equating to 56% over three generations; Partners in Flight 2020). Note, however, that these surveys cover less than 50% of the species's global range. In Europe, the breeding population size is decreasing by at least 30% over 13 years (three generations [Bird et al. 2020]) (BirdLife International in prep.). Overall, the global population is suspected to be stable.
The use of chlorinated hydrocarbons between 1960s and 1970s caused significant reproductive failure: eggshells in Europe showed 13% thinning and in North America 23% thinning (White et al. 2015). With the banning of these pesticides their impact has fallen as indicated by breeding densities and distributions, migration counts and wintering distributions and numbers. However, some individuals may still be impacted (Warkentin et al. 2020), while exposure to mercury is also a cause for concern in some areas (Keyel et al. 2020). The species also suffers collisions with man-made objects (White et al. 2015). Population declines have also been attributed to loss of suitable habitat through overgrazing or conversion of native grassland into cultivated farmland, insensitive management, and increased tourism disturbing nest sites (Konrad et al. 2020). Predation by Red Fox (Vulpes vulpes) is also a threat (Mebs and Schmidt 2006). In North America, falconers harvest a small number of Merlins each year, but this is carefully regulated and is unlikely to have a significant effect on populations (Millsap and Allen 2006). In Ireland, logging of mature trees in conifer plantations may pose a threat to nesting Merlins (pressures and threats data reported by EU Member States under Article 12 of the Birds Directive for the period 2013-2018).
Conservation actions underway
CITES Appendix II, CMS Appendix II, Raptors MOU Category 3, EU Birds Directive Annex I. Covered by North American Christmas Bird Count, with high reliability score. Also covered by North American Breeding Bird Survey, but with low reliability score. Systematic breeding surveys are in place in at least 7 European countries (Derlink et al. 2018).
Conservation actions needed
Continue to monitor exposure of birds to environmental contaminants, including organochlorines and mercury. Further research is needed on the distribution of Merlins at their non-breeding grounds, and habitat use and potential threats in these areas (Warkentin et al. 2020). Maintain interspersed groves of deciduous or coniferous trees for nesting and open grasslands for hunting (Konrad et al. 2020).
Text account compilers
Hermes, C., Haskell, L.
Ashpole, J, Everest, J., Butchart, S. & Ekstrom, J.
BirdLife International (2023) Species factsheet: Falco columbarius. Downloaded from http://datazone.birdlife.org/species/factsheet/merlin-falco-columbarius on 06/06/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 06/06/2023.