Northern Harriers perform a pretty neat trick with their unusually long, slender legs and feet while they’re in flight.
This older photo of a harrier just after take-off at Farmington shows just how long their legs are. It seems logical that those legs and feet could present a potential problem when they’re at cruising speed because anything that might disrupt airflow over their body profile would decrease aerodynamic efficiency and thus require more effort and expenditure of energy to stay airborne. Like most birds, including other raptors, harriers tuck their legs up and against their rump and tail while in full flight but just how effectively do they do it?
1/4000, f/6.3, ISO 500, Canon 7D Mark II, Canon EF 500mm f/4L IS II USM + 1.4 tc, not baited, set up or called in
I photographed this Northern Harrier two days ago as it hunted the edges of Goose Egg Island at Farmington Bay MBR. The image demonstrates how amazingly well their legs and feet become incorporated into the sleek profile of the hawk in flight. Those unusually long appendages seem to virtually disappear, even in such a slender bird. I suspect that their relatively small feet (for a raptor) make this disappearing trick a little easier – in my experience the feet of most other raptors, when tucked, tend to be more conspicuous than those of harriers.
I know I’m not pointing out anything new to most observers but it seems to me that many of us take this disappearing act of bird legs and feet for granted. Some species do it better than others and harriers are some of the best at it.
The adaptations of birds for flight are amazing and this is one I often marvel at in the field, especially in harriers.