ANIMAL ESTATE client 8.11: Peregrine Falcon (UK)
FROM ANIMAL ESTATES 8.0: LONDON
SCIENTIFIC NAME: Falco peregrinus
PROFILE: Peregrine Falcons (a.k.a Duck Hawk, Game Hawk, Great-Footed Hawk) are about the size and weight of a crow (length 34-58cm; wingspan 80-120cm; weight 440-750g). Females (‘falcons’) are up to 30% larger and more powerful than males (‘tiercels’). Adults have slate dark blue-gray wings and backs barred with black, pale undersides, white faces with a black stripe, a ‘moustache’, on each cheek, and large, dark eyes. Their wings are long and pointed and they have a relatively short tail. The RSPB estimates there to be 1,402 breeding pairs throughout the UK.
RANGE: In the UK, the peregrine has a widespread but sparse population range, found more commonly in the upland areas of western England, Scotland and Wales, as well as Ireland. The southeast and east of England play host to much smaller but growing populations. Peregrines are now an established species in the city of London, having a recorded presence since at least 1995, close to Deptford. Since then, they have been recorded further up river, at Silvertown, Greenwich and more central locations such as Marylebone and Westminster. Worldwide, the peregrine is very widespread and can be found on all the planet’s continents except for Antarctica. The home range, or undefended territory, of a Peregrine can extend to up to 27km from the nest, which is normally at least 1km from other nest sites to ensure adequate feeding potential. Peregrines are not migratory birds in the UK and normally spend their whole lives within 100km of their birth place.
HABITAT: Due to their nesting habits, peregrines require very high, stable structures and so can be found more frequently in rocky coastal areas, mountains and hills and sites such as quarries. The similarity of high buildings in cities to these structures has enabled their habitation of urban locations in the UK. It is rare for them to nest in trees. Although they usually require open areas for hunting, this is less significant than the amount of appropriate prey available.
BREEDING AND REPRODUCTION: The Peregrine Falcon mates for life. The breeding season is from August to December and as it nears, unmated males make circling display flights to court females. Mated pairs perform "sky dances" where they swoop and tumble over one another. Pairs nest in crevices in rocks or on the ledges of buildings, often using the abandoned nests of other birds.
Between two and four eggs are laid at a time and if a clutch is lost, another can be laid during the same breeding season. Incubation lasts around 33 days and is predominantly undertaken by the female but the male takes over when the female goes off to feed herself and preen. It takes between 38 and 40 days for newly emerged chicks to fledge and it is at this point when they are particularly vulnerable (see THREATS below)
PREDATION AND HUNTING: The peregrine is one of the most remarkable hunters in the animal kingdom. Whilst cruising horizontally, the peregrine travels at between 40 and 55 mph. However, it has been clocked at over 200mph whilst in a ‘swoop’ for prey and is therefore the fastest animal on record. It usually preys on smaller birds such as doves and pigeons, songbirds, waterfowl, waders and smaller raptors such as kestrels. In London, the prevalence of the feral pigeon makes it a major part of the peregrine’s diet. Although they usually hunt at dawn and dusk, when its prey is most active, researchers have found that they also hunt at night in cities, particularly during migration. This may be because of the effect of city lights or the presence of different prey such as woodcocks or bats. Peregrines usually hunting birds in flight and often kill with the first strike, collecting the victim in the air after having circled around after the initial attack.
THREATS: Like many hawks, the peregrine population was decimated through hunting by gamekeepers in the nineteenth century and although it is now afforded legal protection and increased concern in terms of conservation, this remains an issue. This is particularly of concern in Scotland and in areas where moorland game resides.
The population was also significantly affected by organochlorine pesticides, e.g. DDT, which had destroyed around 80% of the UK population by the early 1960s. Biochemical threats may now be posed in the form of marine pollutants, such as PCBs and mercury, found in seabirds, a constituent part of the peregrine’s diet in coastal areas. In towns and cities, a threat to fledgling peregrines is the lack of intermediate perching space and the sheer sides of the tall buildings where they tend to nest. Young peregrines glide from the nest but, unable to regain height, end up sliding down buildings to ground level, where they encounter various potential threats such as traffic or predators. Although not endangered on a global scale (and are therefore considered of ‘least concern’ by the IUCN), in the UK they are less common and particularly so in the south and southeast. Therefore they are afforded Schedule 1 status under the Wildlife and Countryside Act, 1981.
INTERESTING FACTS: Although peregrine means ‘wanderer’ in Latin, in the UK they tend not to be migratory birds. Peregrines have a strong historical and cultural association with humans. In Medieval England, different orders of falconry were associated with the different strata of feudal society. Easily tamed and adept at hunting, the Peregrine was associated with Princes.
CONSTRUCTING A PEREGRINE NEST BOX: A standard mount nest box is 22" deep, 22" high in the back, 20" high in the front and 34" wide. Use T-111 cedar siding for the outside. T-111 siding is lightweight, easy to get, and very durable. A long arm provides a perch for the falcons. It is important to have about 4" to 6" of pea gravel for nesting substrate. Too little gravel could cause egg punctures. Too much gravel will interfere with drainage, causing the box to rot quickly. Drill 15 to 20 small evenly-spaced holes in the bottom for drainage.
REFERENCES:
Wikipedia
RSPB
BBC Nature
London Peregrine Partnership
The Raptor Resource Project
DEFRA, Wildlife and Countryside Act
Metropolitan Police Wildlife Crime Unit
Hawk and Owl Trust