Winging it

The NaMoPaiMo Facebook page is a treasure trove of wisdom in regards to the art of model horse. While most of the information revolves around finishwork, nothing off limits. Today's guest post come from Lupa, a multiyear NaMoPainter who has been collecting model horses since the very early 1990s. After returning to the hobby several years ago, she focused on customizing vintage Breyer and Hartlands using primarily earth pigments. Some of these models end up with real taxidermy bird wings, which is the subject of this piece. You can find more about Lupa’s work on her webpage. 

Thoughts on Winged Horses

by Lupa

Hey, folks! I’ve been making Pegasus customs with real taxidermy bird wings for over a decade. I want to offer some tips for adding wings with an eye toward both equine and avian anatomy. 

Yes, we are trying to turn a quadruped into a sextuped, but for the most part, artists depicting Pegasus in 2-D or 3-D are trying to emulate a bird’s wings as attached to the upper point of the horse’s shoulder. Placing them in the middle of the back is usually seen as imbalanced; placing them too low on the shoulder interferes with the forelegs. So while we have to take some artistic license given these are fictional beings, we can still do our best to create a believable hybrid.

The first thing to consider is comparative anatomy between horses and birds. Both are vertebrates, and while there are certainly differences in their skeletal structures, they have quite a bit in common, especially with regards to the general overall shape of the skeleton. What we often refer to as the “chest” of a horse is really the anterior end of the ribcage; the entire ribcage is really the horse’s chest in total. You also want to consider how the spine and sternum are more or less parallel to each other in the three example species in the first and second images—the American robin, the ostrich, and the horse.

Now, the thing that sets birds apart from most mammals is that the forelimbs have evolved into wings. Whereas legs primarily use a forward and backwards movement parallel with the sides of the body, wings primarily use an up and down movement perpendicular to the sides of the body. While wings certainly do have some range of motion forward and backwards, it isn’t nearly as pronounced as in a horse’s forelegs, or our arms. This video of an eagle swimming shows a pretty decent range of motion, but a lot of the movement we see in more extreme wing positions has more to do with the spread and bend of the feathers than of the skeletal structure itself.

The same goes for rotational movement in the wings—and forelimbs in general. If you draw a line along the inside of your arm from the shoulder, to the inside of the elbow, and to the inside of the wrist, and then twist your hand forward and backward, most people can twist their hands back about 180 degrees and forward about ninety degrees. However, not everything along that line pivots that far; the line close to where your humerus connects to your shoulder doesn’t pivot as far, and the joint doesn’t have as much range of motion. The part of the forelimb between the elbow and the wrist can twist more than that between the shoulder and the elbow due to the twisting of the radius and ulna. In short, the human arm—and the bird wing—are not like the stiff arms of Barbies and other dolls where the entire arm has to move as one uniform piece when you twist the ball and socket at the doll’s shoulder.

Most of the time, the wing is moving in an up and down motion that is perpendicular to the spine and sternum. Even hummingbirds, which are among the most agile of their kind and have particularly mobile wings, still do not deviate too much from that up and down movement of the skeletal structure. This imagae is a good illustration of hummingbird wingbeats, 

while these photos show hummingbirds at various points in their range of motion. Notice that even when the undersides of the wings appear to be facing forward, they are still more or less parallel with the spine and sternum of the bird—NOT the same as the “chest” (anterior end of the ribcage) of the horse. Notice also that there is significant bend in the feathers that exaggerates the appearance of torsion in the wings, and also when the bird has its head bent down to drink that also creates a greater illusion of torsion. Make sure you are looking at the skeletal structure of the wings in relation to the spine and sternum!

Let’s look more closely at how a lot of the more extreme bending and torsion in bird wings is from the deformation and spreading of the feathers, not the muscle and bone of the wing. Look at this video on how bird wings work and this one on realistic structures for craft and cosplay wings, It’s also SUPER important to watch slow motion videos of birds in flight like this one with birds of many species or this one specifically of hummingbirds. Look closely, and you’ll start to see the difference in the range of motion of the skeletal structure of the wing, and the change in shape of the feathers. But even then—there is a LIMIT to how far those feathers can bend. Primary and secondary wing feathers must have a certain amount of stiffness for the bird to be able to fly. While they have flexibility, they are nowhere near as soft as the rest of the bird’s feathers. If you are depicting a secondary or especially a primary feather bent into an acute C shape, that’s not realistic.

An example of a really unrealistic wing movement is the TriStar Pegasus.

Here the entire underside of the wing from the shoulder to the wrist is turned entirely ninety degrees upward/forward, and is more or less flat. While it makes for a dramatic stylized logo, it isn’t realistic at all. No bird can turn its entire wing that far upward/forward like that. Look these photos, which compare the TriStar Pegasus with one of the upright hummingbirds with “forward facing” wings—the chest of the bird is still analogous to the underside of the horse’s barrel, where the sternum is. The upper surfaces of the hummingbird’s wings are facing the bird’s spine; the upper surfaces of the Pegasus’s wings are facing its butt. Do you see the difference?

Now a good example of realistic wing movement is Ray Harryhausen’s stop-motion Pegasus sculpture from Clash of the Titans. He faced the same conundrum we do in equine modeling—how would a quadrupedal mammal sprout a third set of limbs in the form of wings? We already know that it would be physically and evolutionarily possible, but it’s fiction, so we can suspend disbelief. However, we’re also trying to consider some realistic placement and movement of the wings. I mean, I suppose Mr. Harryhausen could always have Pegasus make big “arm circles” with his wings like a couple of tornadoes on their sides, but he chose a more natural bird-like movement, along with a gentle horse-like gallop, which I think is a nice touch. While there is a slight tilt to the wings, their motion is still largely up and down, perpendicular to the spine and sternum.

The last few pictures show a few of the Pegasus customs I’ve made. 

With real wings it’s easiest to dry them flat, and you can’t easily make the individual primary feathers permanently bend beyond their natural “resting” shape, so there’s not as much dynamic motion as in live birds. But you can see the different ways I’ve positioned the wings to give them some variety in response to the horse’s movement, and some wings, like those of domestic chickens, naturally have more bend. 

Notice, though, that the wings are never rotated ninety degrees away from the spine/sternum the way the Tristar Pegasus’ are. The underside of the Fighting Stallion’s wings, for example, are more or less parallel with the spine and sternum, and while the Gem Twist’s primary feathers have some natural curve, they’re not in an acute C shape and the undersides aren’t facing ninety degrees forward.

Anyway, I hope this all helps! Just as we study equine anatomy for our customs’ accuracy, it’s also important to look closely at avian anatomy for our winged models. Just keep repeating to yourself: spine and sternum! Spine and sternum! Spine and sternum!

Disclaimer: This article mentions the author’s use of legally acquired bird wings for customs; these birds either died of natural causes, or were raised as food on small farms, and none were killed just for their feathers.