After a 16-year absence since the last record of this species on our reserve, an overwintering female on the Old Heath, we are delighted that we have not one, but two Dartford warblers currently wintering on the site. 

From a glance (which many a visitor has discovered, is quite often the only views you get), the Dartford warbler can appear as a small, brownish bird with a distinctively long tail. However, for those who are treated to that characteristic tail-cocked pose, you can soon see the detail that makes this bird rather striking (especially if you're lucky enough to see one in spring). The distinctive red eye ring, the greyish head and that cherry red breast. 

Dartford warblers are a lowland heathland specialist, that requires mature heathland (tall, dense heather and gorse) to breed in, making them one of the latter beneficiaries to any heathland creation or restoration works. They are a species that feed on insects alone and are often seen darting around the heather and scrub in search for scrumptious spiders and other insects.  

This species of warbler is a year-round, UK resident and therefore does not migrate abroad in search of warmer climates over winter, like so many other species. As a result, their numbers and population trends are closely related to the UK weather. Unfortunately, the Dartford warbler is very susceptible to cold winters and especially periods of prolonged snow which drastically reduces their food availability. Unsurprisingly, the UK distribution of Dartford warblers is heavily concentrated south of the Thames due to the warmer climate and available habitat, with sites like RSPB Arne and RSPB Farnham supporting good breeding and wintering populations. It is in these cold spells where they become dependent on areas/blocks of dense gorse to provide the necessary shelter and warmth to survive 

The recent mild winters of the past few years has likely resulted in an increased population as more adults survive and enter the breeding season. This naturally produces more fledged birds, who then spill out in search of their own territories and in this case, with us at The Lodge, at the northern fringe of their range.  

Both birds were recorded within a day of each other. The first bird was located on the 16th October and can be seen or heard from the Skylark Trail, having taken up residency in a dense block of bramble within one of the arable fields.  

The second bird, first sighted on the 17th Octobercan be seen from the seasonal Heathland Trail on our New Heath. This is an area that just days before, was cleared of dense, encroaching birch by our amazing team of volunteersBoth birds are often seen alongside stonechats, which is a species they tend to associate with. We will be closing the seasonal Heathland Trail come January as we look to reduce disturbance to the heathland in the hope of attracting breeding woodlark to the site. So why not come down and see if you can spot this cracking bird! 

Image: Dartford warbler from Skylark Trail 2020 by Steve Rooke

Blog by Alan Kell, Warden