I fired off a couple of shots of an 'adult' Black-headed Gull at lunchtime today. After I looked at the images, I was surprised to see the distinctive black leading edges on primaries 8 and 9, which are indicative of a second winter bird (2CY).
Once upon a time I used to draw and sketch birds. The discipline involved in field sketching seemed to induce a heightened awareness of plumage detail and a keener and more accurate type of observation. In contrast, birding with a camera has possibly reduced my field ability, since the instantaneous record of detail can be achieved without recourse to patient or painstaking observation. Maybe I can stem the tide of my decline though, through the careful examination of images to identify subtle fieldmarks that may, as a result, become increasingly obvious when in the field... I'll find out next time a BhG flies past!