Saker falcon

The saker falcon (Falco cherrug) is a large species of falcon. This species breeds from central Europe eastwards across Asia to Manchuria. It is mainly migratory except in the southernmost parts of its range, wintering in Ethiopia, the Arabian peninsula, northern Pakistan and western China. This species belongs to the close-knit hierofalcon complex. In this group, there is ample evidence for rampant hybridization and incomplete lineage sorting which confounds analyses of DNA sequence data to a massive extent; molecular studies with small sample sizes can simply not be expected to yield reliable conclusions in the entire hierofalcon group. The radiation of the entire living diversity of hierofalcons seems to have taken place in the Eemian interglacial at the start of the Late Pleistocene, a mere 130,000–115,000 years ago; the saker falcon represents a lineage that expanded out of northeastern Africa into the interior of southeastern Europe and Asia, by way of the eastern Mediterranean region. In captivity, lanners and sakers can interbreed, and gyrfalcon-saker hybrids are also available (see bird flu experiment described in 'Ecology and status').The specific part of the scientific name, cherrug, comes from the Sindhi name charg for a female saker. The common name saker comes from the (Arabic: صقر‎, romanized: Ṣaqr) meaning 'falcon'. Saker falcons at the northeast edge of the range in the Altai Mountains are slightly larger, and darker and more heavily spotted on the underparts than other populations. These, known as the Altai falcon, have been treated in the past either as a distinct species 'Falco altaicus' or as a hybrid between saker falcon and gyrfalcon, but modern opinion (e.g. (Orta 1994)) is to tentatively treat it as a form of saker falcon, until comprehensive studies of its population genetics and ecology are available. The saker falcon is a large hierofalcon, larger than the lanner falcon and almost as large as gyrfalcon at 45–57 cm (18–22 in) length with a wingspan of 97–126 cm (38–50 in). Males weigh between 730–990 g (26–35 oz) and females 970–1,300 g (34–46 oz). It resembles a larger but browner gyrfalcon. It is larger and more heavily built than the related lanner falcon. Saker falcons tend to have variable plumage. Males and females are similar, except in size, as are young birds, although these tend to be darker and more heavily streaked. The call is a sharp kiy-ee or a repeated kyak-kyak-kyak. The saker falcon is a raptor of open grasslands preferably with some trees or cliffs. It often hunts by horizontal pursuit, rather than the peregrine's stoop from a height, and feeds mainly on rodents and birds. In Europe, ground squirrels and feral pigeons are the most common prey items. This species usually builds no nest of its own, but lays its 3–6 eggs in an old stick nest in a tree which was previously used by other birds such as storks, ravens or buzzards. It also often nests on cliffs. Saker nests support a species-rich assemblage of commensal insects.