Birds of Britain come in all shapes, sizes and dispositions--from raucous, slender-winged seabirds on the coasts, diminutive warblers and sparrows in backyard gardens, placid, bottom-heavy ducks on lakes to fierce, nocturnal eagle owls. Birders and other wildlife enthusiasts follow basic methods to help identify avian fauna.
Birds are some of the most frequently observed of British wildlife, whether you're looking in a city park, farm field, woodlot or moor. Many kinds are resident to the British Isles, like snipes and robins. A slew of other species, like the little tern and the fieldfare, migrate through or inhabit areas seasonally. They range widely in size: The Dartford warbler may be five inches long, according to the web magazine Birds of Britain, while golden eagles and white-tailed sea eagles have wingspans of more than six feet.
You can find birds anywhere in Britain, but certain general habitats may reveal more diversity. As a general rule, one equally applicable to mammals and many other creatures, the boundaries of different habitats are typically the richest in terms of species variety--an ecological truth known as the "edge effect." Scan hedgerows, the margins of wetlands and the intersection of field and wood. Think about different birds' activity patterns, too, if you're searching for specific species; you won't likely find a barn owl in flight during the afternoon, for example, but might spot one in the dead of night.
Take note of basic physical characteristics like plumage colour and pattern and the size and shape of such features as the bird's bill, wings, tail feathers and feet. Some species with unmistakable, distinctive traits will be obvious even through a quick glance: the common and widespread rook, for example, with its black plumage and heavy beaks. Differentiating between other species may be more difficult: The Kentish plover and the little ringed plover, for example, share many characteristics and the same basic colour pattern of tan, white and black.
Watching a bird's behaviour can also suggest its identity. Even a faraway kestrel, silhouetted black against the sky, gives itself away by hovering in place, pumping its sharp wings furiously as it looks for prey below.
A good field guide and a set of binoculars are the classic tools of the birdwatcher. Magnification is usually essential for discerning identifying characteristics like plumage intricacies and body proportions, and also allows you to observe a bird from a distance, lessening the chances you'll frighten it away. Use an illustrated field guide to select likely candidates for the bird you're observing. Most portray idealised birds---those possessing the most common physical traits---but typically also include colour variants and both immature and mature appearances.