Needle in a haystack....

Today was eye-wateringly cold, but despite the chill I went to Wilstone reservoir to see if there were any med gulls in amongst the thousands of black-headed gulls who roost on the reservoir, choosing to spend the night with their arses immersed in freezing-cold water. One or two were possibles but it was a difficult task in the dimming light picking out the subtle features....this is one of the best things about birding: sometimes it is a real challenge. Indeed, it would soon become tedious if every species were too easily observed. I'll be back tomorrow.....