Cooper’s Hawks – Common but cool

Cooper's hawk 21Oct2016

Cooper’s hawk, Accipiter cooperii

Apparently some hawks think our backyard water feature is their personal smorgasbord. I often see a swoosh of wings go by as songbirds scatter. The Cooper’s hawk, and the very similar sharp-shinned hawk, are frequent visitors to our backyard. Like the jays that always seem to follow me, the Cooper’s hawk has now decided it must be one of my totem animals. I have seen them in a wide variety of habitats here in central Oregon. They always pose nicely for my camera. Here’s a bit more about them…

Range: Cooper’s hawks live throughout the United States, southern Canada, and Mexico. Their breeding range extends from southern Canada southwards to the northern parts of the U. S. They winter and live year-round in the southern and central parts of the U.S. and in Mexico.

Cooper's Hawk 17Nov2016

Identification & unique characteristics: This medium-sized bird has the rounded, broad wings, and relatively long legs that help to identify it as an accipiter hawk. Adults are gray on their backs and on the upper side of their tails and wings. Their head has a darker “cap” and they have red eyes. There are thick dark bands on the tail. Their breasts have orange-reddish bars. Juvenile birds are brown on their upper parts and their breasts are streaked with brown. Their eyes are yellow. This hawk has a length of 14-18 inches and a weight of 8-14 ounces. Females are always larger. Cooper’s hawks fly in a distinctive way – a couple quick flaps and then long glides. This bird is silent much of the time though it does sometimes vocalize with a cak-cak-cak call during the breeding season.

It can be very challenging to figure out if you are seeing a Cooper’s hawk or a sharp-shinned hawk. Cooper’s hawks have a larger head, thicker legs, bigger feet, a paler back of the neck, and a rounded tail with a thicker white tip. The Northern Goshawk looks similar but it is much larger and it has a more distinct white eye stripe.
Cooper's hawk 21Oct2016

Behavior & life history: The breeding season begins as early as March. Courtship includes aerial chases and displays with gliding flights with their wings held up in a ‘V’ position. In bonded pairs, the male does a bowing display to the female before and after building the nest. Cooper’s hawks prefer to build their stick nests 25-50 feet above the ground in trees located in areas with flat habitat. Eggs are incubated for 30-36 days and the young birds are in the nest for 27-34 days. They lay 2-6 eggs. This skillful flier often sits in wait and in a sudden burst of speed captures its unsuspecting prey. They mainly eat birds but also prey on small mammals and, occasionally,  frogs, snakes, and lizards. Bird prey ranges in size from warblers to robins on up to grouse (and chickens!). Cooper’s hawks live up to 12 years in the wild and as long as 20+ years in captivity. Predators of this bird include red-tailed hawks, great horned owls, and raccoons.
CoopersHawk

Habitat needs: Cooper’s hawks live in a wide variety of habitats that include mature forests, mixed woodlands, edges near wetlands, and in open country. They prefer to live in forested lands but are now common in urban and suburban areas. This may be due, in part, to the abundance of rock pigeons, one of their favorite prey species. This bird and other birds of prey are also attracted to backyard feeders.

Status & conservation: This hawk’s population is considered stable at this time. In the past, Cooper’s hawks were adversely affected by the pesticide DDT but after it was banned in 1972 their numbers increased. Since they prey on chickens, they were heavily hunted in the past. One of their names is “chicken hawk.” Cooper’s hawk populations may be affected by habitat loss and degradation.

Interesting fact: Cooper’s hawks do not have the notched bill that helps falcons kill their prey. They kill their prey by squeezing it and sometimes they even hold it under water to drown it.

Buzzsaw Sharks Exhibit

Buzzsaw Shark at HDM September2016

Weird Science

Fossilized teeth that form a shape like a buzzsaw were found in the 1800’s but the type of creature they belonged to was not determined until 2013. A research team consisting of people with backgrounds in art, science, and digital technology solved the mystery. The whorl of teeth belonged to Helicoprion, the buzzsaw shark or whorl toothed shark. This exhibit brings the findings of that research to life through the artwork of Ray Troll and the sculptures of Gary Straub.

Buzzsaw Shark at HDM September2016A massive sculpture of the huge head of a buzzsaw shark bursts through the wall outside of the exhibit at the High Desert Museum and there are additional sculptures and detailed images inside the gallery. A large sculpture of a buzzsaw shark hangs over your head as you enter the gallery. The walls are covered with murals of waves and members of the shark family. Large colorful paintings show the shark family tree and how buzzsaw sharks swimming in the deep may have looked. Glass cases enclose fossils of the odd-shaped whorl of teeth. Projections of that whorl spin across the floor. Framed drawings of buzzsaw sharks hang on the walls. An interactive model of a buzzsaw shark skull shows the action of those formidable-looking teeth. You can sit on a comfy couch (emblazoned with a whorl pattern) and watch a video about the now-extinct shark.

Cheeseburgers?

When I was at the exhibit, I heard a five-year old boy entering the gallery with his family remark, “Wow! Mommy look at that!” Yes, this is a dramatic exhibit that contains a lot of visual interest and fascinating information. The whorl pattern is repeated throughout the exhibit. The artist also had a little fun with the exhibit by hiding several representations of cheeseburgers in the displays. Can you find any of them in the gallery?

Scientific research and art intertwine

buzzsaw3-sioAt first scientists could not figure out what the creature was that possessed the whorl of teeth or where exactly on the animal they were located. The 2013 research team, Team Helico, used CT scans and 3D digital modeling to figure out that it fit into the lower jaw of an ancient shark. Alaskan artist Ray Troll, has been obsessed with the buzzsaw shark for over 20 years and lent his expertise to the team at Idaho Museum of Natural History. Ray is a well-known natural history artist who has lectured at places such as Harvard and Yale. His work has appeared at the Smithsonian and is featured in the current High Desert Museum exhibit.

As part of their research, Team Helico tried to determine exactly how the buzzsaw shark’s jaw worked. It didn’t slice through the head of the shark because it was blocked by small “stops” on the jaw. The team thought it likely that it ate soft-bodied prey because there wasn’t much tooth wear. It probably grabbed and sliced its prey between its tooth whorl and upper jaw and then swallowed it down its gullet.

Buzzsaw Shark at HDM September2016As more and more of the distinctive whorl-shaped fossils were found in the early 20th century, scientists delineated many as separate species. Leif Tepanila and Jesse Pruitt, of the Idaho Museum of Natural History, did further analysis on the fossils and figured out there were only three distinct buzzsaw sharks species.

The teeth themselves are unique among sharks. Unlike other sharks, they formed a whorl as they grew and were never shed. A mature shark could have 150 or more teeth. New teeth form in a “tooth pit” in the back of the mouth and push the whorl forward when they erupt. They switch from being baby teeth to adult teeth at around tooth number 85. No one knows why their jaw has this unusual form.

A team effort

We are always thankful for the work of our staff on setting up exhibits but this particular exhibit was a little different. The artist wanted lots of participation from staff and volunteers on the background work. Images were projected onto the walls and then painstakingly painted by numerous people at the Museum. If you were one of the people who worked on the display, be sure to go into the exhibit to see the final product. The people who participated in this project had a variety of skill levels and some were nervous about doing it “right.” Everyone should be proud of their work because it all came together into a wonderful looking exhibit!

I am reprinting this article I wrote for the October 2016 issue of High Desert Voices, a newsletter for volunteers and staff at the High Desert Museum. The exhibit will be at the Museum until April 23, 2017. NOTE: This exhibit is no longer at the Museum.

To see a fast-speed video of the installment of this exhibit, go here.

Mendel’s Garden

MendelsLupineI think the Gene Jeannie has been at work in my backyard. I planted one purple and white lupine and it has multiplied.  Now I have a violet and purple one, two purple and white ones, a violet and white one, and an all white one.