It’s easy. Experienced birders do it subconsciously, using clues from the wingbeats, rhythm, and path of a bird’s flight. These are usually described in vague terms – the roller-coaster flight of a goldfinch, the slightly undulating flight of a blackbird – but I don’t know of any published effort to really define what is different about each species. To remedy that I thought I would make a start here on a more objective and detailed description of bird flight.
There are several things to watch for:
- The path of the bird through the air, does it travel in a straight line, swoop up and down with bursts of wingbeats, or dart about on an erratic path?
- How many wingbeats are in each burst, and how long is the subsequent pause? Try to get a rough sense of how much of the bird’s time in the air is spent flapping.
- How does it approach the landing? Different species deal with braking and landing in different ways, and this can offer some really good clues for identification.
Three species are shown here as examples, watch for these differences and more, and you’ll discover a wealth of new identification clues.
Song Sparrow (like all Emberizine sparrows) has a flowing and bounding flight style, a few irregular quick wingbeats are followed by a short swooping glide without fully closing the wings. On short flights the tail is pumped vigorously up and down along with each set of wingbeats. As it approaches the landing the bird simply swoops up, swings the tail forward to brake, reaches out with the feet and grabs the perch. A flock of Song, White-throated, White-crowned, etc sparrows all “dive” straight into cover very quickly.
House Sparrow has a more labored and direct flight, with bursts of quick wingbeats and relatively short freefalls. It follows a path with little undualtion and none of the swooping and tail-pumping of Song. When approaching its landing a House Sparrow flaps more quickly and almost hovers before stalling onto the perch. Almost as if the feet are useless and it has to set itself on the perch using just its wings. When a flock flies up into a hedge they hover and buzz around the perches momentarily like a swarm of bees, rather than diving straight in.
Common Redpoll (like all the small finches) has a strongly undulating flight often described as “bounding” or a “rollercoaster”. This path results from the bird giving a very short burst of wingbeats and rising quickly, then folding the wings into a relatively long freefall. Slight changes of direction with each burst of wingbeats give it a subtle zigzag path very different from the straight-ahead path of House Sparrow and some others. When approaching a landing the redpoll swoops, gives just one or two correcting or braking wing flaps, and grabs the perch.