Sparrowhawk

Adult Sparrowhawk in the hand

Sparrowhawk in the hand
Photo: Mike Price

Sparrowhawks can be found over a wide range of habitats from dense forest to open country. They prefer to nest in mature woods, using either broad-leaved, mixed or coniferous woods but can also be found in scrub, windbreaks, large gardens, parks or scattered trees including urban areas, provided there is suitable numbers of prey (small birds).

The Sparrowhawk is one of the most common and widespread birds of prey in the UK. Adults are considered sedentary in the UK and Ireland.

Ringed Sparrowhawk pulli

Ringed Sparrowhawk pulli
Photo: Mike Price

The male Sparrowhawk specialises on small songbirds, sparrow sized passerines forming the most part of its diet, while larger prey is usually taken by the bigger and heavier female (the female is up to 50% larger than the male). They will also occasionally take small rodents if the opportunity presents itself. The birds hunt using a variety of methods including a sit and wait method but usually by taking prey by surprise from flight.

A new nest is normally built each year, and in the upland areas nest sites are usually in large woods with a preference for conifer trees, but will use less favoured habitat when preferred sites are not available.
Nests are usually built in the lower canopy and placed in a fork in the tree or next to the trunk where 2 or more branches grow at the same level. Clutch sizes vary between 3-6 eggs, occasionally 7, hatching around 33 days later and normally fledging around 24-30 days.

sparrowhawk eggs

Sparrowhawk eggs
Photo: Mike Price

The British population of Sparrowhawk is estimated to be 39,000 pairs in 2000, (Baker, H et al 2006). This figure would suggest there is no immediate cause for concern with this species. Along with other raptors Sparrowhawks suffered severely from the effects of organochlorine pesticides over the 1950/60’s. The population recovered quickly when these chemicals were withdrawn and is now believed to be stable. For this reason the species is now listed as of “Green” conservation status.
The species is well represented throughout Northern England.

Sparrowhawks occur as a breeding species throughout the NERF region but are not monitored as a matter of course by the majority of the members. Two NERF member Raptor Study Groups are/have been involved with long-term studies.
Although historically subject to direct persecution by the shooting fraternity this is no longer a significant factor concerning the species’ welfare. Sparrowhawk chicks can be predated by both pine marten and larger raptors such at Goshawk, Buzzard and Tawny Owl.

There are two further issues that result in localised threats; firstly there is a belief amongst some pigeon fanciers that Sparrowhawks are responsible for high mortality rates in some lofts, and secondly there is the erroneous belief, held by some people, that Sparrowhawks are responsible for the long-term declines in songbird populations. As a result of these beliefs there are calls from some quarters for the Sparrowhawk population to be controlled, although there is very little scientific evidence to support these allegations.

The Centre for Ecology & Hydrology are presently monitoring for Polybrominated Diphenyl Ethers (PBDEs) both in infertile/unhatched eggs and the livers of dead birds. More details are available from the Predatory Birds Monitoring Scheme.

References

Baker, H., Stroud, D., Aebischer, N.J., Cranswick, P.A., Gregory, R.D, McSorley, C.A., Noble, D.G. & Rehfisch, M.M. (2006) Population estimates of birds in Great Britain and the United Kingdom. British Birds 99:25-44.