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 increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over 10 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 10 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 9,600-13,600 pairs, which equates to 19,200-27,200 mature individuals (BirdLife International in prep). Europe forms approximately 14% of the global range, so a very preliminary estimate of the global population size is 137,000-200,000 mature individuals, although further validation of this estimate is needed. It has been listed as regionally endangered in North Africa, where the population has been estimated as lying between 130 and 146 mature individuals (Garrido et al. in prep).
The Partners in Flight Science Committee (2021) estimate that the North American population is 400,000 mature individuals. They further estimate that the global population is 1,200,000 mature individuals. The population is placed in the band 100,000-1,200,000 mature individuals.
Over the last three generations (29 years), there has been a 108% increase in the species' population in North America (Pardieck et al. 2019). Other estimates give a much sharper increase between 1965 and 2007 (1,100% increase over 40 years, equating to a 84.2% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). Note, however, that these surveys cover less than 50% of the species' range in North America. The European population is estimated to be increasing (BirdLife International in prep). In North Africa, the population decreased sharply in recent decades, with a reported 35.7% decline in Morocco between 1990 and 2013 (Monti et al. 2013), though the population is now believed to be stable (Garrido et al. in prep). The species also appears to be undergoing a decline in India (State of India's Birds 2021). Overall, the species' global population is estimated to be increasing.
Behaviour Individuals in the tropics and subtropics are resident, but others migrate to the lower latitudes of the Amazon Basin, South America’s northern coast, or West Africa in the non-breeding season (del Hoyo et al. 1994). Migrants begin moving to lower latitudes in August and arrive by October, returning in March and April (Ferguson-Lees and Christie 2001). Birds are generally solitary and usually migrate alone, but may congregate in small groups at roosts or plentiful food sources (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). The species migrates on broad fronts and is not dependent on land bridges during migration (Snow and Perrins 1998, Ferguson-Lees and Christie 2001); birds readily cross bodies of water using flapping flight, but can soar easily over land. It is entirely diurnal (Brown et al. 1982). Habitat It inhabits the areas around shallow waters, being sufficiently tolerant of human settlement to persist in suburban and sometimes urban environments (del Hoyo et al. 1994). Diet Almost its entire diet consists of live fish (del Hoyo et al. 1994). Breeding site Birds usually build large nests high in exposed trees (del Hoyo et al. 1994). Management information Reintroduction has helped populations to recover across parts of its range (del Hoyo et al. 1994).
Human persecution was the main historical threat, prevalent from the 18th-20th centuries (Ferguson-Lees and Christie 2001). A combination of deforestation and the collection of eggs and live birds drove the species extinct in Azerbaijan (del Hoyo et al. 1994).
In the U.S.A. (and to a lesser extent elsewhere), numbers fell significantly from 1950-1970 as a result of pesticide use, although they are now recovering, as they are in Scotland where the species had been extirpated by collection and hunting (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Pesticide use has now been reduced to a minor, and largely historical, threat. However shooting still affects many birds on migration in the Mediterranean (Monti et al. 2018b), as well as wintering birds in tropical regions including Latin America and the West Indies (Global Raptor Information Network 2015). A few Australian birds are apparently impacted by local human disturbance (del Hoyo et al. 1994).
It is very highly vulnerable to the effects of potential wind energy development (Strix 2012). Since 1979, the effect of human activity on osprey mortality has fallen (De Pascalis et al. 2020), though birds are still at risk of deliberate shooting and entanglement in fish nets (ibid, see also Monti et al. 2018b). Though there is no direct evidence for its effect on osprey populations, intensive trawler fishing is likely to deplete fish stocks and affect prey availability. Other fishing practices are also likely damaging; copper sulphate fishing may lead to poisoning and motor boats may disturb osprey nests (Monti et al. 2013). The scale of these threats is unknown.
Conservation Actions Underway
CITES Appendix II. CMS Appendix II. Raptor MOU Category 3. Bern Convention Annex 3. EU Birds Directive Annex I. Barcelona Convention Annex II. There are 1859 Natura 2000 sites designated for Ospreys. It has been included in 38 monitoring schemes across 11 countries (Derlink et al. 2018). The species has been the subject of several recent reintroduction projects (e.g. England [Dennis and Dixon, 2001], Spain [Muriel et al. 2010], Italy [Monti et al. 2014], Portugal [Palma et al. 2019], and locally in the USA [Bierregaard et al. 2014]). The impact of these reintroductions is not well documented (Bierregaard et al. 2014), but there are signs that they have been successful (Ferrer and Morandini 2018).
Conservation Actions Needed
Reduce disturbances during the breeding season by introducing a 200-300 m wide protective zone around nests (Monti et al 2018a). Increase and enforce legislation to protect fish stocks, and investigate effects of current fishing efforts on osprey biology. Enforce shooting bans, or introduce anti-shooting legislation where it is absent. More research is needed into the global population of the species.
Text account compilers
Butchart, S., Ekstrom, J., Khwaja, N. & Ashpole, J
BirdLife International (2023) Species factsheet: Pandion haliaetus. Downloaded from http://datazone.birdlife.org/species/factsheet/osprey-pandion-haliaetus on 29/11/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 29/11/2023.