Late yesterday morning Mark Piper discovered a juvenile Black-throated Diver at the feeder stream end of Stanford Reservoir. It remained quite elusive, diving for long periods of time until it was flushed by a fisherman at 11.35 after which it flew off at tree-top height toward the dam. Subsequent searching failed to relocate it. This morning it was present again close to the Leicestershire side of the reservoir, where Chris Hubbard took the photo below.
It then moved again to the small feeder pool on the opposite side of the road to the reservoir before flying again to the main body of water, remaining in the vicinity of the raft during the early-mid afternoon.
The white flank patch, visible just above the water, rules out Great Northern Diver (as does the relatively narrow bill, absence of both neck patches and bulging forehead) and vagrant Pacific Diver (as does the large bill and absence of chin strap or vent strap).
This is only the nineteenth record for Northants, the last being one at Thrapston GP on 18th November 2001. Ten of the previous eighteen have been at Pitsford Reservoir. It is also the 40th for Leicestershire/Rutland, with most between November and February and 60% of records from Rutland Water, since it was constructed, (Steve Lister in litt).