Wings

One of the delights of living near the US Air Force Academy is watching the various ways the cadets get into the air. There are the small training planes, the gliders, and the air mattress-like parachutes. Every so often, most often during football season and at graduation, we’re treated to an old bomber or two. And then there are the incredible Thunderbirds, whose aerial display comes right over our house. What a view!

Of course, you can immediately tell when the Thunderbirds are in town—you can hear their screaming engines echoing off the Front Range mountainsides. (If you want to actually see the jet, look far ahead of the point  where the sound seems to be originating.) But let’s eliminate the sound for a moment. How can you identify a single-engine prop plane from a glider from a parachute from a jet? Easy—look at the shape of the wing.

Gliders, which have to stay aloft without the benefit of an engine and propeller, have long wings for added lift. The trainers have shorter wings, since they have the added advantage of a propeller. Jet wings are swept back into a triangle shape for maximum speed and minimal air resistance. And parachutes are shaped for maximum air resistance to ensure a gentle landing.

Bird wings also have different shapes for different purposes. I have learned to identify a Swainson’s Hawk, even when silhouetted against the sky, by its extra-long, thinner wings. Like a glider, the hawk needs the additional lift for its hemisphere-spanning migration between the US prairies and the grasslands of Argentina. Red-tailed and Ferruginous Hawks, on the other hand, have broader, shorter wings. They don’t migrate, and the shape of their wings gives them added speed and maneuverability for hunting.

Ornithologists have categorized wing shapes into various types based on shape and how they are used. The problem is that different ornithologists have differing, and often conflicting, categories!  The Cornell Lab of Ornithology lists five: passive soaring, active soaring, elliptical wings, high-speed wings, and hovering wings. Other resources include “High aspect ratio wings” and “Soaring wings with deep slots.” I sorted through all the lists and came up with this summary, which makes sense to me. I hope it makes sense to you as well.

High Lift/Broad Soaring Wings create good lift with little effort, allowing the bird to slowly drift across the sky, taking advantage of thermals while searching for prey. The shorter length of these wings allow the birds to maneuver in a confined area. As an added benefit, many of these birds can spread out their long primary feathers, increasing lift. These broad wings exert a lot of force when the bird is taking off, enabling raptors to lift a heavy meal. Some examples of birds with broad soaring wings include hawks and eagles, vultures, pelicans, geese, and storks.

Long Soaring Wings allow a bird to stay aloft for extended periods without flapping, which is why we also see them on gliders. As the name implies, they are long and narrow. While species with this wing type expend very little effort to stay in the air, the trade-off is a loss of maneuverability. Moreover, these birds often have a difficult time at take-off, requiring a headwind and a long runway. Birds that have long soaring wings include gulls, albatrosses, and frigatebirds.

Red-winged Blackbird_ColumbianDeerNWR-WA_LAH_4298

Elliptical Wings are found on birds that need to maneuver quickly and accurately, either to flit through close vegetation or to nab prey. They offer a quick take-off, but are not built for endurance. Their rounded shape minimizes air resistance. This built-in agility has a cost. The birds typically have a rapid wing-beat. Examples: sparrows, thrushes, crows, pheasants, and this Red-winged Blackbird.

High Speed Wings tend to be of medium length, and narrow with a tapered point. They beat rapidly, allowing the bird to move quickly, but at a cost—all that effort takes a lot of energy. Still, compared to birds with the high-agility elliptical wings, these birds can fly well enough to migrate long distances. You’ll find these wings on species that grab dinner mid-flight, such as swallows and falcons, as well as terns, shorebirds, and ducks.

Black-Chinned Hummingbird_RedRocksRanch-Hwy115-CO_LAH_3761fHovering Wings are specific to hummingbirds. They’re relatively small but move incredibly rapidly, allowing the birds to hover in mid-air, as this Black-chinned Hummingbird is doing.

It helps to learn the different types of wings. Paying attention to the various shapes and proportions allows you to easily tell a gull from a tern, or a falcon from an accipiter. You’ll also learn something about the bird and its lifestyle. I find that makes birding a whole lot more interesting.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s