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 appears 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 very 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 84,100-252,000 pairs, which equates to 168,000-505,000 mature individuals (BirdLife International 2015). Europe forms c. 5% of the global range, so a very preliminary estimate of the global population size is 3,360,000-10,100,000 mature individuals, although further validation of this estimate is needed. The population is therefore placed in the band 3,000,000-10,499,999 mature individuals.
The population is suspected to be stable in the absence of evidence for any declines or substantial threats. The European population is estimated to be increasing (BirdLife International 2015).
This species's range spans southern Europe and sub-Saharan Africa. The largest proportion of breeding individuals in Europe (>80%) are found in Spain (Ibanez-Alamo et al. 2019). Great Spotted Cuckoos that breed in southern Spain cross the western Sahara Desert along the East Atlantic Flyway during their post-breeding migratory route to their non-breeding grounds in the Sahel region (Ibanez-Alamo et al. 2019).
The species uses semi-arid open woodland, scrub, rocky hillsides in dry savannas and dry cultivation. In Europe the species favours savanna-like heathland, often with cork oak (Quercus suber) or stone pine (Pinus pinea), as well as olive groves. It is a brood parasite of crows and magpies in the Mediterranean, particularly Black-billed Magpie (Pica pica), Azure-winged Magpie (Cyanopica cyanea) and Carrion Crow (Corvus corone) in Spain and Egypt, Pied Crow (Corvus albus) in Africa and and in west, east and southern Africa it will also parasitise starling nests (Payne and Garcia 2013). The female can lay 12–25 eggs in one season, often laying several eggs per nest. It feeds on insects, mainly large hairy caterpillars, also termites, grasshoppers, moths and small lizards. The species is migratory. Most European birds migrate to Africa, wintering north of 10°N but possibly many move south of the Sahara; small numbers winter in southern Spain. Movements throughout range are poorly known as breeding and non-breeding birds are indistinguishable (Payne and Garcia 2013).
Hunting and traffic accidents are the main causes of mortality in southern Europe. In Crete it is preyed upon by Eleonora's Falcon (Falco eleonorae) (Erritzøe et al. 2012).
Conservation Actions Underway
Bern Convention Appendix II. There are currently no known conservation measures in place for this species in Europe.
Conservation Actions Proposed
Research should be undertaken to assess the impact of hunting and traffic accidents to inform future conservation measures.
Text account compilers
Butchart, S., Ashpole, J & Ekstrom, J.
BirdLife International (2023) Species factsheet: Clamator glandarius. Downloaded from http://datazone.birdlife.org/species/factsheet/great-spotted-cuckoo-clamator-glandarius on 01/06/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 01/06/2023.