August at Nanjizal

Whilst September is the official start of autumn, migration has been in full swing at Nanjizal during August. During the month, there was no coverage from the 14th-20th (peak Sedge Warbler passage) due to family holidays and a short period at the start of the month. None the less, a non-too-shabby total of 1,698 new birds was achieved. Unlike a lot of coastal sites, good numbers of birds at Nanjizal usually coincide with still clear nights where the birds can pick good habitat, rather than being happy to land on the first bit of land they see whilst flying through inclement weather. As you can see from the totals the main species trapped are species that have a tendency to migrate SSW in autumn, with Sedge Warbler and Blackcap both funnelling down in big numbers. This funnel affect also brings a good number of dispersing British Robin, as we always get good numbers at the end of August into September. Other species such as Willow Warbler are never in such large numbers.

Top 10 species ringed in August

Sedge Warbler	837	Reed Warbler	80
Whitethroat	192	Grasshopper Warbler	56
Willow Warbler	176	Robin	56
Blackcap	107	Wren	25
Chiffchaff	102	Garden Warbler	14

Ringed birds recaught during the month came from Scotland, Leicestershire, Wales, Cheshire and Belgium, all bar one being Sedge Warblers. Most species seem to have done OK, with Whitethroat, Blue Tit, Great Tit and Grasshopper Warblers picking up after a slow start. Song Thrush seem to have done very well locally. Other unusual species ringed included seven Tree Pipit, two Firecrest and two Spotted Flycatcher.

The month also saw a few rare and scarce birds appear in the nets, predominantly birds from the south, as there hasn't been much arriving on the east coast to filter down. A blast of south-eastlies on the 22nd seemed to do the trick and a good run started with a Wryneck on the 24th, white-spotted Bluethroat on the 25th (one of 224 birds ringed that day). The 26th then produced the second Melodious Warbler of the month (the first was on the early date of 10th) and for the second month in a row a Blyth's Reed Warbler, this time a first-year bird.

Blyth's Reed Warbler at Nanjizal - a first for Cornwall

In what didn't look like overly-promising weather, the regular autumn mist-netting at Nanjizal continued this morning, producing 93 birds, including five Reed Warblers, four Grasshopper Warblers, three Garden Warblers and what must surely be one of the birds of the autumn in the county! Blyth's Reed Warbler is a long-overdue bird for Cornwall (with a single record from Devon eclipsed by five in Dorset and no fewer than five on the Isles of Scilly), but this didn't detract from the excitement of finding one in a mist-net!

So here are just a few photos and details of the bird, with no doubt more to follow...

Blyth's Reed Warbler will always be a difficult bird to identify in the field, but the rounded wing,
with very short primary projection, can be seen in this bird. Also note the indistinct supercilium,
broad-based bill and the forehead peaking behind the eye.

The identification clincher can be seen in the open wing, with both P3 and P4 (primaries) emarginated:
the narrowing of the outer web of the feather towards the tip of the wing.
On other 'reed' warblers this emargination is only seen on P3.

As if we need to plug the site even more, but any visiting ringers wanting to join the ringing group at Nanjizal can find out more details elsewhere on the blog.