Blyth’s Reed Warbler 8th September 2022 – a New Bird for Stanford & Northamptonshire

Chris, our Sightings Officer has written up an account of another exciting warbler which was ringed at the reservoir last year. Remember too, to have a look at previous year's reporting in our rivetting annual reports, which can be accessed from http://www.stanfordrg.org.uk/

Ringing activity at Stanford Reservoir tends to moves up a gear in the autumn.  The 8th September presented perfect conditions to ring, so Mick Townsend (MJT) and Adam Homer (AGH) were out early erecting a number of nets in Blower's Lodge Bay on the Northants side of the reservoir. Chris Hubbard (CMH) was on site to take on the scribing duties for the first couple of rounds, which do tend to be the busiest.

Around 80 birds were brought back from the first round and MJT and AGH commenced the process of ringing these. MJT got to bird number four which was clearly an acrocephalus warbler. It is worth pointing out that the ringing group have ringed over 7000 Reed and 4 Marsh Warblers in their 40 years at the site. Each bird is carefully checked to establish the wing measurements and the position of the P2 notch. On completing the initial check MJT immediately said that the measurements didn’t fit Reed and it could be a Blyth’s Reed!

Before a bird is ringed it should be positively identified so MJT went about gathering key data and referring to Svensson's Identification Guide to European Passerines whilst AGH continued the process of ringing the other birds. Key biometrics were obtained and cross checked with Svensson, confirming MJT’s initial thoughts that this was indeed a Blyth’s Reed Warbler. CMH continued to scribe whilst also documenting the key biometrics on the BTO Rarity Recording Form. The bird was ringed and then a number of photographs were taken, two of which are included below. The bird was subsequently released in Blower's Lodge Bay and the enormity of what had happened began to sink in. The bird was not seen again after it’s release. The record was subsequently accepted by the Northants Records Committee as the first Blyth’s Reed Warbler for Northamptonshire.

Key Identification Points
    • Primaries emarginated P3 to P5 – only P3 in Reed / Marsh.
    • P2 notch =12mm = tertials.
    • Wing length – 63mm.
    • Rounded wing.
    • Short primary projection.
    • Forehead peaking behind the eye.
    • Fairly indistinct supercilium behind the eye.
    • Lower belly whitish. 

A feather that was dislodged in the ringing process was subsequently sent to Martin Collinson at the University of Aberdeen for DNA analysis. The team confirmed the bird was A.dumetorum, Blyth’s Reed Warbler.

Written by Chris Hubbard, Mick Townsend and Adam Homer