Words: Kate Risely, of the British Trust for Ornithology (BTO)
A Hobby is always an exciting sight – hunting low over a pond or reedbed, or as a Swift-like silhouette high overhead. Seeing just one is enough to make my day, so I was amazed to hear of 61 birds seen together at Lakenheath in May this year.
Hobbies are known to congregate at good feeding sites when they first arrive back in the UK, before dispersing to their breeding grounds, but I doubt that many people are lucky enough to see so many together.
The breeding Hobby population in the UK is mostly restricted to England, though the range is expanding as the population increases. In the 1950s, the UK population was estimated to be around 100 pairs, mainly on southern heathland and downland, and the 1968-1972 Breeding Atlas showed that these birds were restricted to western parts of southern England at that time.
Since then, Hobbies have spread northwards, possibly due to changes in dragonfly and beetle populations, their main food supply. They are also increasingly found in farmland, seemingly less dependent on their traditional heathland habitats.
By the time the 1988-91 Breeding Atlas was published, Hobbies were breeding across much of England, having colonised eastern areas, and spread north to the Humber.
Today, maps of Hobby sightings submitted to BirdTrack look similar to the 1988-91 distribution map, but for the best current information we will have to wait until the 2007-11 Bird Atlas is completed. It appears, however, that Hobby numbers are increasing, even if their distribution is not changing significantly – the latest results from the Breeding Bird Survey show that Hobbies have increased by 23% since the start of the survey in 1994.
The last population estimate, in 2001, put the population size at 2,200 pairs, but numbers are now almost certainly higher than that.
Since their diet consists primarily of insects, Hobbies spend the winter in Africa, unlike any other British falcon, but in common with the European species Lesser Kestrel, Red-footed Falcon and Eleonora’s Falcon.
It is interesting that their populations are increasing, unlike so many of our other sub-Saharan migrants, which are showing severe declines. It would appear that Hobbies, as birds of prey, have not encountered the same problems on migration and on their wintering grounds as our migrant songbirds.
It is not known exactly where British Hobbies spend the winter, as there have never been any ringing recoveries south of Spain – and no Hobbies ringed anywhere in Europe have been recovered south of the Sahara. Most ringed Hobbies recovered in Europe on migration appear to have been heading in a south-westerly direction, towards West Africa, but the main wintering area for this species is believed to be the Zambezi basin.
On their breeding grounds in the UK, Hobbies generally lay their eggs in June, meaning that the chicks hatch in July, and, all being well, fledge in August. Since this species is secretive when breeding, one of the easiest ways to confirm breeding is to watch and listen for groups of newly-fledged young, sitting together on branches near the nest site.
All breeding records will be useful for the 2007-11 Bird Atlas, particularly in order to detect any expansion of the breeding range. I’ll be keeping an eye out for recently fledged young in Thetford Forest – and I’m also planning to visit Lakenheath in May next year!