The peregrine falcon (Falco peregrinus) is a medium-sized raptor found across much of the world. In the UK, the peregrine falcon suffered a major decline in the mid-20th century due to the impacts of organochlorine pesticides such as DDT. Following the ban on these chemicals in the 1960s and 1970s, the peregrine population has rebounded strongly. Peregrine falcons are now found across many parts of the UK, though their status varies in different regions. Overall, the species has recovered well and their conservation status is relatively secure, though they still face some ongoing threats.
What is a peregrine falcon?
The peregrine falcon is a distinctive raptor with long, pointed wings and a streamlined body shape adapted for speed. Adult peregrines have bluish-grey upperparts and barred underparts. Their most striking feature is the dark moustachial stripe on each side of the white face. Peregrines hunt other birds in flight, using spectacular stoops where they dive at extreme speeds. They nest on cliffs, buildings, and other tall structures, laying 3-4 eggs per clutch.
Some key facts about peregrine falcons:
– Wingspan ranges from 90-120 cm
– Length is 34-58 cm
– Weighs 500-1500 g
– Dives at over 300 km/h, making it the fastest animal on Earth
– Nests on cliffs, crags, tall buildings; also adapts to urban habitats
– Feeds primarily on mid-sized birds such as pigeons and ducks
The peregrine is found on every continent except Antarctica. There are 19 recognized subspecies globally. In the UK, the breeding population is the nominate subspecies F. p. peregrinus.
Historical population trends
Native UK population before the 20th century
The peregrine falcon has likely bred in the UK for thousands of years. Before the 20th century, the peregrine was considered a common cliff-nesting raptor in many regions. However, there are no comprehensive historical surveys, so population sizes are uncertain. Peregrines were persecuted in some areas, but not enough to significantly impact overall numbers. The pre-20th century population was estimated at 500-1000 breeding pairs.
Serious decline in mid-20th century
The peregrine population in the UK crashed catastrophically after the Second World War. By 1962, there were no breeding pairs recorded in England, Wales or the Channel Islands. Only a handful remained in Scotland and Northern Ireland. This represented a decline of at least 90% from historical levels.
The almost total collapse was caused by organochlorine pesticides such as DDT, dieldrin, and aldrin. These chemicals accumulated in the peregrine’s tissues, causing eggshell thinning and breeding failure. Because peregrines are apex predators, they were exposed to high concentrations through bioaccumulation up the food chain.
Recovery after pesticide ban
Following the ban on organochlorines, peregrine numbers began to slowly recover. Populations were bolstered by reintroduction programs, which released over 2000 captive-bred birds at sites around the UK between 1975-1994.
As the pesticide residues left the ecosystems, peregrines were able to breed successfully again. Numbers steadily increased through the 1980s and 1990s. By the early 2000s, the overall UK breeding population had rebounded to around 1500-1700 pairs – roughly similar to pre-pesticide levels. However, the distribution across the UK had changed significantly.
Current status and distribution
Widespread distribution, but variable across regions
Peregrines now breed in all parts of the UK, but their status varies in different regions:
– **England:** Around 1100-1300 breeding pairs, widely distributed across uplands, coasts and quarries. Also increasingly nesting in urban areas.
– **Scotland:** An estimated 500-600 breeding pairs, mainly in the Highlands and on remote coasts and islands.
– **Wales:** Approximately 150-250 breeding pairs, concentrated in the north and west.
– **Northern Ireland:** Around 30-50 breeding pairs, scattered at coastal and upland cliff sites.
So while peregrines are again widespread, their numbers are notably higher in England and Scotland compared to Wales and Northern Ireland. Their affinity for nesting on quarries and buildings has greatly assisted the recolonisation of England in particular.
Higher densities in some regions
Although broadly distributed, peregrine densities are higher in areas of upland moorland and along rocky coasts. Major population centres include:
– Northern England moorlands (e.g. North York Moors, Peak District)
– Southern uplands of Scotland
– Coastal cliffs and islands of western Scotland
– Coastal cliffs in southwest England and Wales
– Quarries in the Cotswolds
– Large cities, especially along major rivers (London, Bristol, Liverpool, Manchester etc)
So while the peregrine has recovered well overall, it remains scarce or absent across significant areas of lowland Britain.
Threats and conservation issues
While peregrines have rebounded strongly, they still face a range of ongoing threats and conservation issues:
Illegal persecution
Peregrines are still deliberately killed or have their nests destroyed in some areas, usually on pheasant and grouse shooting estates. However, the rate of illegal persecution has declined significantly since the 1990s.
Disturbance
Outdoor recreation activities like climbing and caving can disturb sensitive nest sites, causing breeding failure. Many popular nesting cliffs receive protection during the breeding season.
Declining prey populations
Peregrine populations may be limited in some regions by declining prey populations. For example, major declines in upland wading birds could restrict peregrines on moorlands.
Pollutants
While organochlorines are banned, peregrines are still exposed to other pollutants like flame retardants from electronics waste. The impacts are unknown but concerning. More research is needed.
Climate change
How climate change may affect peregrine populations is unclear. Changing precipitation and vegetation patterns could potentially reduce habitat suitability in some regions.
Urban threats
City-nesting peregrines face hazards like wall-ledges being repaired, nests being disturbed, and fledglings colliding with windows. However, most city populations remain stable or increasing.
Legal protection and conservation actions
Legal protections and conservation efforts have been critical in the peregrine’s recovery:
Full legal protection
Peregrines receive full legal protection under the Wildlife and Countryside Act 1981. It is illegal to intentionally harm, disturb or interfere with peregrines, their nests, or eggs. Stronger penalties apply during the breeding season.
Ban on organochlorines
The banning of harmful pesticides like DDT allowed peregrine breeding success to return to normal levels and populations to recover.
Listed as a UK BAP priority
Peregrines were designated as a priority species under the UK Biodiversity Action Plan (UK BAP) from 1995-2006. This required conservation actions to support the recovery.
Reintroduction programs
The release of over 2000 captive-bred peregrines from 1975-1994 helped restore populations across the UK. Urban reintroduction projects helped colonise cities.
Monitoring and research
Monitoring of breeding populations guides conservation actions. Tracking studies have provided insights into peregrine movements, survival rates and causes of mortality.
Nest site protection
Many important nesting cliffs are given seasonal access restrictions to prevent disturbance. Some urban nest sites also receive direct protection.
Future outlook
The peregrine falcon has made a tremendous recovery in the UK over the past 50 years. Populations are now relatively secure, and some further growth is expected in certain regions. However, peregrines face ongoing threats including illegal killing, disturbance, declining prey populations and exposure to pollutants. Continued monitoring and conservation action will be needed to ensure their populations remain healthy in the long-term. Key actions include:
– Continuing legal protection and enforcement against persecution
– Monitoring breeding populations and productivity
– Managing disturbance at sensitive nest sites
– Research into pollutant impacts and prey availability
– Protecting upland habitats and restoring degraded habitats
– Maintaining urban nest sites through cooperation with land owners
– Public education and engagement campaigns
If such conservation efforts continue, the future prospects look positive for the peregrine to remain a widespread and iconic predator in the landscapes and cities of the UK. Their remarkable recovery stands as a true conservation success story.
Year | UK population estimate | Status and key events |
---|---|---|
Pre-20th century | 500-1000 pairs | Common and widespread |
Early 1960s | 10-20 pairs | Catastrophic crash due to pesticides |
Early 2000s | 1500-1700 pairs | Recovered due to legal protection and reintroductions |
Present | 1300-1600 pairs | Relatively secure, but some ongoing threats |
Summary of current status:
- Around 1300-1600 breeding pairs in the UK
- Widely distributed, but variable across regions
- Higher densities along uplands, coasts and quarries
- Increasing in urban areas
- Recovered from pesticide crash, but some ongoing threats remain
- Given full legal protection
- Conservation dependent, but future prospects are positive