Pel's Fishing-Owl

Identificazione

Pel's fishing owl is one of the largest owl species in the world. Among the world's owls, it ranks as the fifth-heaviest on average, the seventh-longest in length and measured wing chord, and fourth-longest in mean wingspan, although not all large species have had measured wingspans. It measures 51–63 cm (20–25 in) in length, spans around 153 cm (60 in) across the wings and weighs up to at least 2.35 kg (5.2 lb). One male was found to weigh 1.72 kg (3.8 lb) and four females averaged 2.19 kg (4.8 lb), it may outrival the snowy owl (only around 4% lighter on average in six datasets) as the fifth- or sixth-heaviest living owl on average. Under current classification, it is the heaviest extant owl outside of the genus Bubo, although some authors may also include the fishing owls in Bubo. Among standard measurements, the wing chord is 40.7–44.7 cm (16.0–17.6 in) and the tail is 20.7–24.3 cm (8.1–9.6 in) long. They are well adapted to their aquatic lifestyle. Unlike most owls, they have minimal feathering on their toes and the tarsi, thus minimizing the amount of plumage that gets wet while fishing. Like diurnal raptors that specialize in fish, they have spiky scales on the bottoms of their feet that help them grip slippery fish. Since hearing and auditory stealth is not important to its hunting techniques, this owl does not have strong hearing and does not have the soft edges to its flight feathers that most owls share, which makes them almost impossible to hear in flight.<p>Adults are colored a rich ginger-rufous with dense dark bars to the upperparts and scaling to the underparts. The feathers around the head are loose and long, giving the head a shaggy appearance. The tarsi and toes are unfeathered and straw-colored. The white throat is often largely obscured, but can be puffed up in displaying birds during courtship. The flight and tail feathers are barred with lighter and darker feathers. The eyes are distinctly dark, often blackish in color. The two adult sexes are similar looking, but females are generally less rufous in color and have a more indistinct facial disc. Considerable variation exists in coloration and barring in adult birds, with some birds having extensive pale feathers with others having several blackish markings. Juveniles are more uniform buff than adults. Unlike the eagle-owls, the ear tufts of the Pel's fishing owl are barely visible, giving it a very round-headed appearance. The two related fishing owls are smaller and lack the dark barring and scaling (though they do have dark streaks below).<p>The song of the male Pel's fishing owl is a deep, sonorous, horn-like boom, first a single and then a higher pitched huhuhu. The male also utters a ringed hoot, much higher pitched than those of most eagle-owls, followed by a deep, soft grunt: whoommmm-wot or hooomm-hut. The calls of the male are repeated every 10 to 20 seconds and can be heard from up to 3 km (1.9 mi) away. While singing, the male's throat and breast are often highly inflated. The female's songs are similar, but are higher pitched and even in a double-note, i.e. hoot-oot. Females and young at the nest wail a shrill wheeoouu while anticipating food.

Tassonomia

The species' common and specific name honours Hendrik Severinus Pel, who was governor of the Dutch Gold Coast (now Ghana) from 1840 till 1850.

Nome scientifico

Scotopelia peli

Autorità

Bonaparte, 1850

Ordine

Strigiformi

Famiglia

Strigidae

Genere

Scotopelia

Areale e habitat

It is found throughout a large part of sub-Saharan Africa, but it is generally rather local, uncommon, and absent from drier regions. It is patchily distributed in Nigeria, Senegal, the Gambia, Guinea, Sierra Leone, and in central Africa from the coast to eastern Zaire and discontinuously to South Sudan, Somalia, Kenya, and Tanzania and southwards to Zambia, Zimbabwe, Botswana, and eastern South Africa.<p>Pel's fishing owl is found in forests along rivers and lakes. It can be found in swamps and estuaries at sea level up to an elevation of around 1,700 m (5,600 ft). Its favorite habitat is riverine forests with large trees, although large numbers are also found on islands with large, old trees within larger rivers, swamps or lakes, so long as the islands are not too far from the bank. The species is largely residential and has no seasonal movement, although young, nonbreeding birds may wander somewhat before claiming their own territories. Pel's fishing owl may move outside of its own range in pursuit of prey.

Migrazione

Specie stanziale

Comportamento

Comportamento migratorio: Specie stanziale.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione