The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa.
The realm consists of several bioregions: the Mediterranean Basin; North Africa; North Arabia; Western, Central, South and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions.
The white-tailed eagle (Haliaeetus albicilla), sometimes known as the "sea eagle", is a large bird of prey, widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which also includes other diurnal raptors such as hawks, kites, and harriers. One of up to eleven members in the genus Haliaeetus, which are commonly called sea eagles, it is also referred to as the white-tailed sea-eagle. Sometimes, it is known as the ern or erne (depending on spelling by sources), gray sea eagle and Eurasian sea eagle.
While found across a wide range, today breeding from as far west as Greenland and Iceland across to as far east as Hokkaido, Japan, they are often scarce and spottily distributed as a nesting species, mainly due to human activities. These have included habitat alterations and destruction of wetlands, about a hundred years of systematic persecution by humans (from the early 1800s to around World War II) followed by inadvertent poisonings and epidemics of nesting failures due to various manmade chemical pesticides and organic compounds, which have threatened eagles since roughly the 1950s and continue to be a potential concern. Due to this, the white-tailed eagle was considered endangered or extinct in several countries. Some populations have since recovered well, due to governmental protections, dedicated conservationists and naturalists protecting habitats and nesting sites, partially regulating poaching and pesticide usage, as well as careful reintroductions into parts of their former range.
The little owl (Athene noctua), also known as the owl of Athena or owl of Minerva, is a bird that inhabits much of the temperate and warmer parts of Europe, the Palearctic east to Korea, and North Africa. It was introduced into Britain at the end of the 19th century and into the South Island of New Zealand in the early 20th century.
This owl is a member of the typical or true owl family Strigidae, which contains most species of owl, the other grouping being the barn owls, Tytonidae. It is a small (approx. 22 cm long), cryptically coloured, mainly nocturnal species and is found in a range of habitats including farmland, woodland fringes, steppes and semi-deserts. It feeds on insects, earthworms, other invertebrates and small vertebrates. Males hold territories that they defend against intruders. This owl is a cavity nester, and a clutch of about four eggs is laid in spring. The female does the incubation and the male brings food to the nest, first for the female and later for the newly hatched young. As the chicks grow, both parents hunt and bring them food, and the chicks leave the nest at about seven weeks of age.
The Eurasian wren (Troglodytes troglodytes) or northern wren is a very small insectivorous bird and the only member of the wren family found in the Old World, specifically in Eurasia and Africa (Maghreb). In Anglophone Europe, it is commonly known simply as the wren. It has a very short tail which is often held erect, a short neck and a relatively long thin bill. It is russet brown above, paler buff-brown below and has a cream buff supercilium. The sexes are alike.
The species was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes pacificus of western North America as the winter wren. The Eurasian wren occurs in Europe and across the Palearctic – including a belt of Asia from northern Iran and Afghanistan across to Japan. It is migratory in only the northern parts of its range. It is also highly polygynous, an unusual mating system for passerines.
The ruff (Calidris pugnax) is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia. This highly gregarious sandpiper is migratory and sometimes forms huge flocks in its winter grounds, which include southern and western Europe, Africa, southern Asia and Australia.
The ruff is a long-necked, pot-bellied bird. This species shows marked sexual dimorphism; the male is much larger than the female (the reeve), and has a breeding plumage that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers that inspired this bird's English name. The female and the non-breeding male have grey-brown upperparts and mainly white underparts. Three differently plumaged types of male, including a rare form that mimics the female, use a variety of strategies to obtain mating opportunities at a lek, and the colourful head and neck feathers are erected as part of the elaborate main courting display. The female has one brood per year and lays four eggs in a well-hidden ground nest, incubating the eggs and rearing the chicks, which are mobile soon after hatching, on her own. Predators of wader chicks and eggs include mammals such as foxes, feral cats and stoats, and birds such as large gulls, crows and skuas.
The Eurasian magpie or common magpie (Pica pica) is a resident breeding bird throughout the northern part of the Eurasian continent. It is one of several birds in the crow family (corvids) designated magpies, and belongs to the Holarctic radiation of "monochrome" magpies. In Europe, "magpie" is used by English speakers as a synonym for the Eurasian magpie: the only other magpie in Europe is the Iberian magpie (Cyanopica cooki), which is limited to the Iberian Peninsula. Despite having a shared name and similar colouration, it is not closely related to the Australian magpie.
The Eurasian magpie is one of the most intelligent birds. The expansion of its nidopallium is approximately the same in its relative size as the brain of chimpanzees, gorillas, orangutans and humans. It is the only non-mammalian species known to pass the mirror test.
The black-headed gull (Chroicocephalus ridibundus) is a small gull that breeds in much of the Palearctic in Europe and Asia, and also locally in smaller numbers in coastal eastern Canada. Most of the population is migratory and winters further south, but many also remain in the milder areas of northwestern Europe. It was formerly sometimes cited as "common black-headed gull" to distinguish it from "great black-headed gull" (an old name for Pallas's gull).
The genus name Chroicocephalus is from the Ancient Greek words khroizo, "to colour", and kephale, "head". The specific name ridibundus is Latin for "laughing".
The Pacific wren (Troglodytes pacificus) is a very small North American bird and a member of the mainly New World wren family Troglodytidae. It was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes troglodytes of Eurasia as the winter wren.
It breeds along the Pacific coast from Alaska to California and inland as far as Wyoming and the Black Hills of South Dakota. It migrates through and winters across the western half of the United States and Canada.
Cottus is a genus of the mainly freshwater ray-finned fishes belonging to the family Cottidae, the typical sculpins. They are often referred to as the "freshwater sculpins", as they are the principal genus of sculpins to be found in fresh water. They are native to the Palearctic and Nearctic.
They are small fish, mostly less than 15 cm (6 in) in length, although a few species can reach twice that size.
The pied wheatear (Oenanthe pleschanka) is a wheatear, a small insectivorous passerine bird that was formerly classed as a member of the thrush family Turdidae, but is now more generally considered to be an Old World flycatcher (family Muscicapidae). This migratory central Asiatic wheatear occurs from the extreme southeast of Europe to China, and has been found wintering in India and northeastern Africa. It is a very rare vagrant to western Europe.
The male is a boldly marked white-and-black bird. The white crown tinged with brown contrasts with the black face and throat and white rump. The female is browner, and the head is washed with sandy buff. Females are darker than the females of the northern wheatear, look smaller and show less white on the rump. The tail feathers are white with characteristic black markings, which form an inverted black "T" pattern that resembles the tail of the western black-eared wheatear. This 14 centimetres (5.5 in) bird nests in open, stony, sparsely vegetated regions, laying four to six eggs in a hole, under a stone or in a rock crevice. The pied wheatear primarily eats insects but will also take seeds.