Tawny owls are one of the most common owl species found in the UK and across Europe. However, even though they are widespread, their populations have declined in recent decades making them a species of conservation concern.
The tawny owl (Strix aluco) is a medium-sized owl found throughout much of Europe and parts of western Asia. It is also sometimes known as the brown owl. Tawny owls are highly adaptable birds that can thrive in both rural and urban environments, provided there is tree cover for roosting and nesting. They are typicallyfound in mixed woodlands, parks, gardens, and even built up areas.
Across its widespread range, the tawny owl is not considered globally threatened. The IUCN Red List categorises it as a species of Least Concern. However, in the UK, tawny owl populations declined by 30% between 1995 and 2008. The species was therefore added to the UK Red List as a species of conservation concern. Recent estimates suggest the UK population is continuing to decline to around 45,000 territories.
UK Population and Distribution
In the UK, the tawny owl has a widespread distribution across England, Wales, Scotland and Ireland. It is found across most of mainland Britain, Ireland and some Scottish Islands. The tawny owl population is estimated to be around 45,000 territories in the UK.
Tawny owls show distinct regional variationsin their distribution across Britain:
- In England, they are widespread and commonly found across most counties.
- In Scotland, they are widespread across mainland areas but more localised on islands. Found on Skye, Mull, Islay, Jura and Arran butscarcer or absent from more remote islands.
- In Wales, widespread across mainland areas.
- In Ireland, found commonly across the island of Ireland, including Northern Ireland.
Within its range, tawny owls occupy a variety of wooded habitats including deciduous and mixed woodlands, parks, gardens, orchards and tree lined waterways. They can also persist in urban areas provided there are trees, parks and gardens offering nesting sites.
Population Declines
As an adaptable generalist species, tawny owls were once considered commonand widespread across Britain. However, breeding bird survey data collected since the mid-1990s onwards revealed concerning population declines:
- Between 1995-2008, tawny owl populations declined by 30%.
- Between 1995-2011, populations declined by 28%.
- The estimated UK population in 2011 was 45,000 breeding territories.
These declines meant the tawny owl was uplisted from the Green List to the UK Red List as a species of conservation concern. The species remains in decline but at a slower rate in recent years:
- Between 2011-2017, populations declined a further 7%.
- The estimated UK population is now around 45,000 territories.
Drivers of Decline
The drivers behind declining tawny owl populations are likely to be multifaceted. Some potential causes contributing to declines include:
Habitat Loss
Loss of habitats such as woodlands, hedgerows and treelined waterways may reduce availability of nesting sites. Conversion of natural mixeddeciduous woodland to conifer plantations likely reduces habitat suitability.
Reduced Prey Availability
Small mammal populations fluctuate naturally but lows can impact owl breeding success and survival. Wider biodiversity declines may be reducing prey availability long term in degraded habitats such as intensively managed agricultural land.
Climate Change
Milder winters benefit small mammal prey, but wetter weather during the breeding season reduces hunting success which could negatively impact owl productivity. Extreme weather events may also impact survival.
Increased Predation
Predators like red fox, pine marten and other owl species may increasingly predate eggs or juveniles. Tawny owl nests on the ground or in tree cavities are vulnerable.
Vehicle Collisions
As tawny owls forage along roadside verges, collisions with vehicles may be a significant cause of mortality for adults and dispersing juveniles.
Secondary Poisoning
Consuming poisoned rodents may cause lethal secondary poisoning,especially from second generation anticoagulant rodenticides(SGARs).
Conservation Status
The tawny owl has the following conservation designations:
- IUCN Red List: Least Concern
- UK Red List: Red list species of conservation concern
- Bern Convention: Appendix II
- Birds Directive: Annex II
In the UK, tawny owls are listed on the UK Red List as a species of conservation concernbased on moderate ongoing population declines. The species is also protected under the Wildlife and Countryside Act 1981 which makes it illegal to intentionallykill, injure or take a tawny owl, take or damage its eggs, or disturb active nest sites.
Rarity Compared to Other Owls
The tawny owl is one of five resident breeding owl species regularly found in Britain. How does its rarity andconservation status compare?
Species | Population Estimate | Population Trend | Conservation Status |
---|---|---|---|
Tawny Owl | 45,000 territories | Declining (-7% from 2011-2017) | Red List |
Barn Owl | 4,000 pairs | Declining (-31% 1995-2011) | Red List |
Little Owl | 5,700 territories | Declining (-64% 1979-2008) | Red List |
Long-eared Owl | 4,400 pairs | Stable | Amber List |
Short-eared Owl | 2,800 pairs | Declining | Red List |
This comparison shows that the tawny owl has undergone less severe declines compared to the barn owl and little owl. However, the tawny is more common than those species. Its large population size means it isnot considered rare. The long-eared owl is probably rarer overall despite being stable.
Reasons Tawny Owls Remain Relatively Common
Several ecological factors explain why tawny owls are still widespread and relatively abundant compared to other UK owls:
- Generalist habits – Tawny owls have diverse habitatpreferences and are not reliant on any specialised or rare habitat types likeold growth forests. They can adapt to urban areas.
- Resident habits – As a non-migratory species, tawny owls don’t face pressures on migration or threats on wintering grounds thatmigratory owl species encounter.
- Prey generalist – Tawny owls can prey switch between small mammals meaning they are resilient to fluctuations in a single prey species.
- Nest site flexibility – Tawny owls will use tree cavities but also readily take to nest boxes allowing them to breed successfully in modifiedhabitat.
- Large clutch size – Tawny owls lay large clutches, typically 2-4 eggs,improving odds of breeding success.
Thanks to these key adaptable traits, tawny owls remain widespread and are not considered rare in a UK context. Nonetheless, moderate but sustained population declines mean they are now a priority for conservation action under the UK Red List classification.
Conclusion
In conclusion, the tawny owl has an extensive range across the UK and Europe. Its large population size means it cannot be considered a rare species. However, UK tawny owl populations have declined by around 30% since the 1990s. Continuing declines haveseen the tawny owl Red Listed as a species of conservation concern. Compared to other UK owls, the tawny remains relatively abundant. Its success is down to its generalist habits and adaptability. But ongoing pressures including habitat loss may see populations decline further without conservation intervention.