The Wisconsin DNR recently shared a stunning photo captured by a trail camera in the Snapshot Wisconsin program. The reddish feathers of the Red-tailed Hawk are impressive, but my eye was quickly drawn to the bird’s wide wings and a rarely-seen group of feathers.
See the original photo here.
The alula feathers (indicated by the arrows in the photo) usually lay flat on the wing and camouflage with the other flight feathers. Aptly named as a “winglet” in latin, this section of feathers connects to a separate bone, akin to our thumbs, that can move independently. While landing, as in this photo, the alula spreads to increase the surface area of the wing. The small change in wing shape increases lift to assist with landing on a perch, dropping down on prey, or slow flight. Even airplanes have been designed with this feature in mind: slats on the leading edge of aircraft wings extend when landing on the runway.
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