Lifestyle

Tuesday, Mar 12 2013 12:01 AM

Pen in Hand: Wonder Bird; a closer look at a Redtail's superpowers

Related Photos

Dragons are real, and they have feathers: a Red-tailed Hawk. Note the eye ridge above the eye, which serves to protect the bird's eyes from weather, debris and glare. Photo by Jon Hammond

Two feet tall with a four-foot wingspan, Redtails are big and tough. Photo by Jon Hammond

Scimitar feet -- a Redtail's grip is many times stronger than that of an adult human. Photo by Jon Hammond

A Red-tailed Hawk's vision is estimated to be six to eight times better than that of a person, hence the term "hawk-eyed" for people with great eyesight. Photo by Jon Hammond

The most common raptor in the Tehachapi Mountains, and throughout North America, is the Red-tailed Hawk (Buteo jamaicensis). This is the iconic raptor of the West and the one that people are most likely to recognize: the large size, broad wings, distinctive brick red tail, dark hood and downward slurring, whistling scream uttered while "making lazy circles in the sky" make this the archetypal bird of prey. Why is this familiar raptor so successful? There are a number of reasons, but it is illuminating to take a closer look at this bird's amazing abilities to understand why it thrives in some many places.

Red-tailed Hawks are so formidable that if a person possessed some of their physical characteristics, that individual would be considered to have superpowers. Let's start with their incredible vision: diurnal (daytime active) raptors have proportionately large eyes, almost 1.5 times as large as similar-sized birds that aren't raptors. They also have about twice as many rod and cone cells inside their retinas as humans, which gives them tremendous visual acuity -- a Redtail's vision is estimated to be six to eight times better than a person's. Rods are more sensitive to light, but give no color information, while the less sensitive cones enable color vision.

This greatly heightened visual resolution comes at a price, however: Redtails have poor vision in low light conditions, so they generally perch after dark and try to avoid flying at night. Owls, on the other hand, have eyes with many rods that are able to function well in low light conditions, but have few cones so they aren't good at distinguishing color, which isn't much of an issue since colors aren't readily discernible at night anyway. Redtails are believed to have less color awareness than humans, and their typical plummage of brown, gray, black and white tones suggests that color is unimportant to them. Most predators are geared more to seeing movement than color so that they can concentrate on seeing prey animals move -- color can often be a distraction, more hindrance than help.

Red-tailed Hawks and other raptors have a prominent eye ridge above each eye that acts like a visor or the brim of a hat, protecting the bird's eyes from wind, dust and rain while also reducing glare. Their eyes have very limited movement inside a bony socket, so they must turn their heads to look from side to side. There is much more that could be said about a Redtail's eyes, but now let's take a look at their main weapons: their curving spike-tipped feet.

Redtails have bright yellow legs with three forward-facing toes and one backward-facing toe. These would look not unlike the feet of a chicken, except for the fact that each toe is equipped with a wickedly sharp curved talon that's about a half an inch long. Redtails can lash out incredibly quickly with their talons, and once they've successfully grabbed something, not much can escape from a set of Redtail talons. I have been grabbed repeatedly over the years by Redtail talons, and I never fail to be impressed at the intense strength of their grip. The hawk on this page managed to squeeze two talons into my hand, and it wasn't the talon that entered the fleshy part of my palm that got my attention as much as the one that effortlessly pierced the nail bed of my right thumb, with blood starting to ooze out of my nail before I'd even managed to convince the bird to let me go.

For the sake of comparison, a human grasping a broomstick is estimated to exert about 20 pounds per square inch (psi), while a Bald Eagle grasping a fish might exert 450 psi. Redtails aren't as strong as eagles, but their grip is almighty strong, trust me. They are also equipped with "ratchet tendons" on the underside of their toes that enable them to keep closing their grip smaller and smaller without exerting more force. This ratcheting mechanism enables them to bind tightly to prey or to maintain a grip on a tree branch while sleeping on a windy night. At times raptors have difficulty loosening this ratcheting feature, and Ospreys (Fish Hawks) are occasionally drowned when they sink their talons into too large a fish and are pulled underwater before they are able to release.

There are many other qualities that make Redtails so successful, including their sharp tearing bill, ability to go days without food, seeming indifference to cold weather, and more. A mature female Redtail (like most raptor species, females are 15-25 percent large than males) is about two feet tall with a roughly four-foot wingspan, and this incredibly tough flight

machine only weighs a little more than three pounds. A falconer who was asked about Red-tailed Hawks described them in this way: "A Redtail is definitely the bird I would recommend flying to anybody. They are about as tough as any bird can get, and if you are willing to be grabbed a few times along the way by a moody giant bird, then you will get a lot in return."

The Redtail in these photos was found near death from starvation, weighing less than a pound, and three weeks and two more pounds later, it flew away without a backwards glance, the picture of health.

Have a good week.

JON HAMMOND has written for the Tehachapi News for more than 30 years. Send email to: tehachapimtnlover@gmail.com.

Photos by Jon Hammond

Print

This Week's Real Estate

Local Advertisers

Social Tehachapi

Updates from local businesses