Birds of prey are also termed “raptors”, derived from the Latin rapere, meaning to take or seize by force. They are characterised by sharply curved bills, powerful feet with large talons, exceptional eyesight in diurnal species and specially adapted hearing in nocturnal species. The Falkland Islands has seven species of raptor: six of these are represented in this issue; the seventh is the Turkey Vulture, Cathartes aura falklandica, a New World vulture.
31p Barn Owl Tyto a. tuidara
The Barn owl is a nocturnal bird of prey which utilises special adaptations in its hearing to locate its prey in the dark. Asymmetrically placed ear openings mean that sound reaches one ear slightly before it reaches the other, allowing the owl to pinpoint where the sound is coming from, without needing to see the prey. The shape of the bird’s facial disc effectively funnels sound towards the ear openings, and the Barn owl, like other owls, has exceptionally soft feathers with a special comb-like edge to allow completely silent flight. In the Falkland Islands, the main prey species of the Barn owl is the House mouse, but rats also make up a percentage of their diet.
Found in every continent except Antarctica, there are approximately 35 different races of the Barn owl recognised across the globe.
31p Short-eared Owl Asio f. sanfordi
The Short-eared owl is a striking-looking owl with bright yellow eyes. A partly diurnal species that usually inhabits dense stands of grass such as Tussock, Cinnamon or Blue Couch in the Falklands, this owl makes its nest on the ground. Like the Barn owl, the Short-eared owl also preys upon mice and rats, but may take small rabbits or birds if given the opportunity. The Short-eared owl possesses the same special adaptations for hunting in the dark as the Barn owl, but has larger feet and talons for handling slightly larger prey. Owls usually swallow their prey whole.
On New Island, where this photo was taken, Short-eared owls are rare, possibly due to the very large population of Striated caracara, a potential predator, which breed there.
76p Red-backed Buzzard Buteo polyosoma
The Red-backed buzzard is also known as the Variable hawk, due to its individual variation in plumage. Young birds can range from a dark chocolate with bright yellow legs and cere, to russet red, to very pale and mottled. Adult females usually have a white breast and a blue-grey head, with rusty red plumage on their backs, (giving the species its name), whereas adult males are usually white with a blue-grey back and head.
A diurnal bird of prey and the only buzzard species found in the Falkland Islands, the Red-backed buzzard prefers to hunt small, mammalian prey such as mice, rats and rabbits. Like all raptors, the buzzard uses its powerful feet and sharp talons to catch and immobilise its prey. Unlike the nocturnal hunters, diurnal raptors use their exceptional eyesight for locating the prey; a buzzard’s visual acuity may be 6 to 8 times better than ours.
76p Crested Caracara Polyborus p. plancus
The largest of the Falkland Islands’ birds of prey, the Crested caracara, also locally known as the ‘Carancho’, is a close relative of the much bolder, Striated caracara. Quite different in character, behaviour and appearance from the Striated, the Crested caracara is slowly becoming more common and widespread in the Islands, although it is a shy species and susceptible to disturbance. This species usually prefers low, rocky cliffs for a breeding site, but it will also take advantage of large trees where it will build a substantial nest of twigs.
On New Island, where this photo was taken, the Carancho preys mainly on rabbits and Thin-billed prions, but will readily scavenge for carrion.
£1.01 Peregrine Falcon Falco peregrinus cassini
Known as the fastest creature in the animal kingdom, the Peregrine falcon is an incredible aerial hunter, capable of reaching speeds of up to 200mph in a stoop or dive. This falcon mainly hunts birds, perfectly able to take species as large as a Patagonian Crested duck, but more commonly hunting small petrel species, or passerines such as the Falkland thrush. Usually the impact of the strike from a Peregrine would be sufficient to kill its prey, but this species also possesses very powerful talons with enormous crushing power.
Quite an elusive falcon, the Peregrine usually nests on precipitous cliffs, well out of sight. They are, however, quite vocal when defending their territory from unwanted visitors such as buzzards, and the fledged young can quite readily be seen as they practice their hunting skills at the end of the breeding season.
£1.22 Striated Caracara Phalcoboenus australis
The Striated caracara, more commonly referred to as ‘Johnny rook’ in the Falklands, is probably our best-known bird of prey. The Falkland Islands supports the World’s largest population of this characterful bird, which is actually a rare member of the falcon family.
An extremely bold and curious bird by nature, the Striated caracara utilises these unique characteristics in its pursuit for prey, with young birds often forming a ‘gang’ and taking on a pack mentality for hunting. Adult caracaras are extremely proficient hunters and although they are perfectly skilled in the air, they usually take their prey on the ground and can often be observed running; not a typical raptor characteristic! On New Island, Striated caracaras feed almost exclusively on Thin-billed prions and the eggs and chicks of Rockhopper and Gentoo penguins, but this species is an opportunist and will take a huge variety of prey and carrion.
Designer & Photography: Georgina Strange
Printer: BDT International Security Printing
Perforation: 14 per 2cms
Stamp size:30.56 x 38mm
Sheet Layout: 10
Release date: 13 January, 2016
Production Co-ordination: Creative Direction (Worldwide) Ltd