Early this morning I found a lone gull perched on a straw bale at Mercers Lake at Holmethorpe Sand Pits. Just a Black-headed Gull but it looked good perched there with its mirror-image reflected on the water. A couple of quick digiscoped shots and on I moved on.
A few more shots of a Garden Warbler and a while spent listening to the rattling songs of Lesser Whitethroats and the rhythmic outpourings from a couple of Reed Warblers before the steady stream of dog-walkers and joggers started to spoil the tranquility of the morning.
Then the question came that I always dread: "Seen anything good?" which is always followed, before I get chance to answer, by the intricately detailed account of how last week they saw a big bird with grey and black and white on it and how it must have been a stork because it was eating the goldfish in their back garden pond!
As I get older I find myself becoming less tolerant of my fellow humans and resort to telling them that it probably was a stork in the hope that this will satisfy them and they will quickly b*gger off and leave me alone!
Rant over, back to the subject I was originally posting. It wasn’t until I returned home later in the morning and downloaded my photos, that I realised that the bird that I had presumed to have been a Black-headed Gull, appeared on the photo to have a black hood and black bill, not a chocolate-brown hood and red bill. It also showed no white spots on the primaries and surely the grey on its wings was too dark to be that species.
I knew that the bird was back-lit when I took the photo, but the evidence was there before me. Could this possibly be a Bonaparte’s Gull? This bird just didn’t look quite right to be a Black-headed Gull going by the photo. No other gulls on the lake at the time meant that size comparison was impossible.
The tension and excitement built, but I am always realistic about such matters. If it was a rare gull, how come I didn’t notice anything unusual about it when I took the photo? I told myself to keep calm, and do my homework on this gull before reporting it.
A few text messages, phone calls and emails later and I had contacted everyone that I knew had a knowledge of gulls (I am useless at identifying them myself).
Slowly the trickle of replies came back and by 8.30 p.m. it became clear that this bird’s legs were too long and its bill too thick to be a Bonaparte’s Gull and its hood didn't extend far enough down the rear of the crown. It was just a Black-headed Gull whose photo had been taken in adverse lighting conditions.
So the black hood and black bill were just effects of the lighting conditions and the camera’s attempt to set it’s own exposure.
Again this proves both the value of, and the problems that can occur, in getting photographic evidence. It provides the chance to prove or disprove a sighting, but it also shows how easy it is to fool one's self into believing that the common species you were observing is something a lot rarer. Digiscoping has its limitations.
Was I disappointed? After all this would have been a life tick for me had it been a Bonaparte's. No, not really, it is just another species to look for in the future.
My sincere thanks go to Dave Harris, Johnny Allan, Gordon Hay, Steve Gale, Matt Farmer and all the other birders who took the time and trouble to study the photos and identify the bird correctly for me.