The Long-eared owl is a rarely seen owl of woodland. Widespread in Ireland and northern England, it is patchily distributed elsewhere and seems to do better where Tawny owls are rare/absent. Despite being famed travellers (one was captured just over 3,200 km / 2,000 mi from its ringing site), a lack of winter migrants has, we think, resulted in a decline in winter roosting birds in Britain in recent years.
That which follows is a summary of Long-eared owl natural history. The detailed article for this species is in preparation.
The Long-eared owl at a glance
Four subspecies recognised, with Asio otus otus the one found in UK.
Size: Medium-sized owl standing 35-40cm (14in) tall and with a tail 12-16cm (5.5in). Wing span up to around 80cm (2.5ft). Weigh up to 430g (15 oz.).
Colour/Appearance: Light/buff brown with dark brown/black streaks and spots, pale ochre face disc rimmed with black. Head feathers primarily dark brown, with paler fringes. Dark brown feathers give the appearance of ears.
Distribution: Reasonably widespread in Britain and Ireland, although not particularly common. Absent from most of south-west England and southern Wales. Apparently suffers from competition with Tawny owls, possibly explaining why it is not found in the New Forest (high Tawny density), but does well over the Solent on the Isle of Wight (no established Tawny population). Most Scottish birds are summer visitors while species is resident in much of Ireland, excluding and area in the central-west of the country. RSPB estimate between 1,500 and 4,780 breeding pairs in the UK.
Longevity: Captive birds may live for 28 yrs, although 15 yrs is probably upper limit in wild.
Sexing: Calls sexually distinctive. Male song is deep ‘whooh’, while female call is weaker and more nasal in character.
Activity: Nocturnal with activity beginning at dusk; spends day roosting against tree trunks. Generally sedentary species.
Territory/Habitat: Open countryside with tree stands, hedges, pasture etc. May roost in deciduous or coniferous forests, orchards, parks, cemeteries and even larger gardens. Territories vary with food supply (typically 50-100ha / one-fifth to one-third of sq-mile), although neighbouring pairs may be as close as 50-150m (160-320ft).
Diet: Predominantly small mammals, with short-tailed voles of particular importance. Will take other vertebrates, including birds up to about pigeon-size, and insects. Birds appear particularly important during the summer.
Reproduction: Often uses abandoned nests of other birds (esp. other raptors) into which 4-5 eggs are laid during March/April. Incubation lasts around 4 weeks and chicks leave the nest flightless at about 25 days old. Chicks can fly by around 35 days old and follow their parents who continue to feed them for another couple of months. Usually one clutch per year; two in good vole years.
Behaviour and Sociality: Monogamous during breeding season and, despite being territorial, several pairs may live close-by – how close determined by food supply. Male and female make tinny ‘watt-watt-watt’ sound when disturbed.
Threats: Locally persecuted (shot) and vulnerable to pesticides and road traffic – in Germany ~25% study population died on roads each year.
Nick Baker’s British Wildlife: A month by month guide - by Nick Baker
New Holland Publishers -- 2003 -- ISBN: 978-1845171131
Wild Animals of Britain & Europe - by Helga Hofmann
Collins -- 1995 -- ISBN: 978-0007627271