A routine ringing session at Stanford Reservoir this morning produced Northamptonshire’s fourth-ever Marsh Warbler.
It was trapped, ringed and released along the rear edge of Blower’s Lodge Bay at approximately 11.00. Thanks to Chris Hubbard for the images below.
The lack of contrasting rufous rump (of Reed Warbler) is an immediate pointer to identification, as are the pale-tipped primaries, although they are not as obvious as on some Marsh Warblers. Also pale fringes to tertials are more obvious than on Reed Warbler.
Marsh Warbler’s slightly shorter bill, plus eye-ring and supercilium equally distinct compared to Reed Warbler’s, are just about visible in the above image. Visually, though, they are still difficult to tell apart!
Marsh Warbler is just about hanging on as a rare breeding species in the UK, with perhaps only eight pairs restricted to sites on the east coast. Otherwise, it is a rare migrant.
Interestingly, two of the previous three records are from Stanford and include one trapped on 17th June 1984 and a singing male on 16th May 1989. The third was a singing male at Stanwick GP, twenty years ago, on 7th-9th June 1998.
Please note access to Stanford Reservoir is by permit only, issued by Severn Trent Water Authority.