Press Releases - May/Jun 2006 - Item 4

No. 2006/05/21
May 2006

Tawny Owl ate my goldfish!

It’s not just the Barn Owls on BBC’s Springwatch that are having problems breeding this year, Tawny Owls are also not having a good 2006. Low numbers of prey have meant that many owls aren’t bothering to breed this year and many of those that are, have been forced to be more catholic in their diet, bringing unusual items to young chicks.
What effect will this have on the owl population?

Tawny Owls are traditionally one of the UK’s earliest breeding species but they appear to have got off to a very poor start in 2006. Volunteers collecting information for the British Trust for Ornithology’s (BTO’s) Nest Record Scheme have reported declines of up to 80% in the number of sites containing breeding owls this spring from sites as far a field as Cheshire, Manchester, Lancashire, Lincolnshire and Norfolk. Those that have attempted to raise a brood started late, laying relatively few eggs and raising fewer chicks. The high number of unusual prey items found at nest sites – including birds, frogs and even a goldfish! – suggest that low numbers of their more traditional rodent prey might be responsible for their poor breeding performance in 2006.

“Poor weather conditions during the winter made it hard for the owls to hunt. This weather also reduced the size of mouse and vole populations, leading to owls having to feed on more unusual prey such as goldfish,” says Dr Dave Leech, Head of the BTO’s Nest Record Scheme.

But what does this mean for breeding Tawny Owls?

“If the birds start the year in poor condition, they may delay their breeding until the following year when they have more hope of raising a family. This certainly seems to be what we are seeing at the moment with many nest sites deserted and pairs just not breeding,” Dave adds.

Concerns were already growing for the species, as circumstantial evidence suggested that Tawny Owl numbers might have declined during the last decade. In an effort to find out what was really going on, the BTO launched its Tawny Owl survey in 2005, a repeat of a survey run in 1989. The results, which are soon to be published, will provide the first estimates of Tawny Owl population changes in the UK.

Notes for Editors

1) Tawny Owl Facts. Tawny Owls normally lay 2-3 eggs which are brooded entirely by the female. They are early nesters, laying their first egg from mid to late March. Tawny Owls typically live for 5 years but the oldest recorded wild individual was 21 years and 5 months old. Tawny Owls set up their territories in the autumn and it is at this time that they are at their most vocal. The well known “hoot” call is mainly given by the male and the ‘kerr-wick, kerr-wick’ call by the female. Data from the 1989-1991 Breeding Bird Atlas estimated a British population of 20,000 pairs. However, this information is now fifteen years old and more recent evidence from general bird surveys, aimed largely at day-flying birds, suggest that numbers may have fallen by up to a third since 1994. The recent BTO Tawny Owl survey seeks to get a more accurate population estimate.

2) Barn Owl Facts. There are 4,000 pairs of Barn Owls nesting in the UK. Barn Owls are birds of farmland, especially in southwest Scotland, northwest England, the English/Welsh border, western Wales, southwest England and East Anglia. A pair of Barn Owls needs to find about 4,000 small rodents (each weighing around 20g) in order to successfully raise a brood of young. The oldest recorded Barn Owl was 13 years and 4 months old. Sadly, lots of these owls meet untimely ends as they try to get to grips with a world dominated by man. For instance, a large proportion (45%) of ringed Barn Owls are reported as road casualties. A slightly less predictable cause of death is drowning in water troughs; this mainly seems to be a problem for breeding females, desperate to bathe after weeks sitting on their eggs

3) Colour photographs. Images of Tawny Owls are freely available for use in association with this press release. Please contact

4) The BTO has an ISDN line available for radio interviews.

For further information please contact:

Martin Fowlie or Dave Leech on 01842 750050 or email (during office hours)
Out of office hours, please telephone: 07704 847935 (mobile)

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