Tuesday, March 25, 2008

Great Horned Owl--Bubo virginianus

Great Horned Owl near the Huntington Central Park Library in Huntington Central Park in Huntington Beach looking back at me.
I was looking through my camera at a Great Horned Owl just before noon in Huntington Central Park over by the library. A lady passing by wanted to know what I was looking at. I pointed out the Great Horned Owl up in the tree. "How did you see that?" she asked. I replied, "I saw an unexpected dark spot in the branches, looked through my binoculars, and there he was." It was the middle of the day, and he was in a tree overlooking a field often seemingly alive with California Ground Squirrels. He appeared to be resting. When he saw me looking at him, he looked back with almost equal curiosity. He was well camouflaged, and I almost missed him. Both the color and barred pattern of their feathers blend in with the tree bark making Great Horned Owls very difficult to spot. Although they do have a small white bib under the chin, it is not enough to make them stand out. In the case of the Great Horned Owl I saw in Central Park, it was just the unexpected shape that made me double check to see what it was. I did not expect a Great Horned Owl since they are hard to spot in the day time.

Great Horned Owl--Courtesy US Fish and Wildlife--Photographer Ronald Laubenstein

I remember one time I was birding with my friend Gloria, and we saw what at first glance appeared to be a cat in a low tree. It turned out to be a Great Horned Owl. Some people call them the "cat owl," They do in some ways look very like a cat--especially the eyes and "ears." The "ears" are tufts of feathers and not ears at all. I have heard theories that the feathers help guide sound onto the facial disk and into the ears and that the ear-like feathers are camouflage to keep the Owl from being seen. The bird's actual ears are holes under the feathers on the side of its head. The ears are placed on the head asymmetrically so the owl can locate sounds more precisely. This is a distinct advantage at night in locating moving prey on the ground.

Presentation on the Great Horned Owl from Cascades Raptor Center in Eugene, Oregon

Great Horned Owls begin hunting at dusk and continue all night long. You may see them just before sunset and near dawn. They hunt by sound, locating prey precisely using their asymmetrical ears, and by sight with their enormous yellow eyes. The must turn their head to see rather than move their eyes because their eyes are so large that there is no room left over for muscles to move their eyes. They have no significant sense of smell. Sometimes they come out during the day, but the harassment from crows and hawks can easily drive them under cover. Sometimes they are found by other birds while sleeping and harassed or "mobbed" out of the area. They often share territory with diurnal birds of prey like the Red-tailed Hawk. The Red-tail has the day shift and the Great Horned Owl has the night shift. In areas with no diurnal predator, they may come out earlier in the day.

"Click" an owl at Wildbirds Unlimited, Huntington Beach brought there by South Bay Wildlife Rehab. Giving me the eye.

Great Horned Owls are large--about two feet tall. Like many raptors, the female is larger than the male. They weigh between 3-4 pounds and have a wingspan of between 3-5 feet. They hunt from perches or fly low along the ground to catch prey. On occasion, they actually walk along the ground to hunt prey. Their biggest asset is surprise which they usually can accomplish with specialized feathers that make their flight virtually silent.

Great Horned Owl in the Orange County Zoo in Irvine Regional Park in Orange, California . His "ears" are laid back. The "ears" are actually tufts of feathers. Check out those feet. Very powerful talons.

Great Horned Owls, like all raptors, grasp and kill their prey with their large talons. The prey has little chance. Armed as they are, a Great Horned Owl's greatest enemy is another Great Horned Owl. They eat rabbits, hares, gophers, other rodents, skunks, raccoons, bats, Great Blue Herons, Red-tailed Hawks, turkeys, geese, ducks, and other birds large and small, reptiles, frogs, and even insects like crickets and worms. They pretty much eat whatever they catch including domestic animals and pets. They are the only animal which regularly eats skunks.

Click, the Great Horned Owl.

Great Horned Owls are so strong that they are able to kill and carry prey that weighs up to three times their own body weight. Small prey is swallowed whole like we swallow popcorn. Larger prey is taken to a perch or safe area. There,the Great Horned Owl tears the prey into smaller size pieces with its hooked, black beak. Several hours after they eat, the owls regurgitate a large pellet of fur and bones and other indigestible animal parts. You can see what they ate by separating out the pieces in the pellet. Sometimes in places where owls have been roosting on a regular basis, you can see lots of pellets.

Short Great Horned Owl Documentary from Berwick Productions on YouTube

Great Horned Owls are found in most of North America. Their range covers all of the United States and then south through Central America and portions of South America. They live in arctic, desert, and tropical climates. They are generally nonmigratory except in the extreme northern regions. If you have forests, parks, or trees and grass near you, it is likely there are Great Horned Owls nearby. They live in remote areas like forests and in neighborhood parks. Great Horned Owls have been able to disperse widely in the Americas. They are one of the most common owls in North America.

Courtesy US Fish and Wildlife Service-- Great Horned Owl Chick--Photographer Gary M. Stolz

Great Horned Owls make a variety of sounds from hoots, to screeching, to loud clicking or clacking. The most well known sound is the hoo-hoo sound that seems so mysterious late at night. The males have lower voices in general than females. Great Horned Owls make noise to find mates, to intimidate rivals, and unnerve prey.

"Click" a Great Horned Owl from South Bay Wildlife Rehab photographed at Wildbirds Unlimited, Huntington Beach. It was fun to shoot photos of all the raptors they brought that day. This owl was very impressive.

Owls live to about 13 years old in the wild and close to 30-40 years old in captivity. Captivity gives them food, shelter, and safety from the hazards of man. It is quite a bird.

A short interview with zookeeper and Olivia, a Great Horned Owl, at the Oakland Zoo.

Great Horned Owls are solitary creatures and mate for the breeding season. Afterward, the revert to their solitary ways. They are very poor nest builders and often recycle the nest of a crow, hawk, or eagle. In January and February they hoot and display to find mates, so listen and see if you can hear any Great Horned Owls in your neighborhood. The reason they nest early like many hawks do, is that Spring is a time of year where there is much prey to be had as other animals and birds raise young. That way the Great Horned Owl and other raptors have plenty of food for their own young.

Side View of "Click."

They lay between 2-5 eggs. Both male and female incubate the eggs and feed the young. The young jump from branch to branch until fully fledged and able to coordinate their movements. Young are covered in white down. No ear tufts are usually visible. I remember being on a field trip to Antelope Valley, and coming across two young Great Horned Owls with their parents at a pool in an agricultural field. They were jumping from branch to branch clumsily, but seemed on the point of learning to fly at any time. It was very cute. Great Horned Owls young stay with the adults until early fall. The parents are very protective and will attack animals or birds or even you if you approach too closely.

Click on his perch.

Don't forget to look carefully during the day when you are birding to see if you see a shape that just might be a resting Great Horned Owl. If there is a ruckus and crows and hawks are mobbing something, check and see if it is the Great Horned Owl. You never know, you just might see a Great Horned Owl yourself.

OC Birder Girl Links

Huntington Central Park
Irvine Open Space Preserve Nature Center
Irvine Regional Park in Orange, California
Mason Regional Park
San Joaquin Wildlife Sanctuary
Tewinkle Park -- Costa Mesa
Barn Owl--Tyto alba

Red-Shouldered Hawk

Red-Tailed Hawk--Buteo jamaicensis

External Links and Resources

All About Birds: Great Horned Owl

Detailed article.

Animal Diversity Web: Great Horned Owl

Great profile full of information from the University of Michigan--student project.

BirdWeb: Great Horned Owl

Desert USA: Great Horned Owl

Very good article on Desert USA.

Great Plains Nature Center

Fun little article that urges people to get out and hoot on winter evenings to see if they have any owls.

Internet Bird Collection: Great Horned Owl

Very good quality videos of Great Horned Owls.

National Geographic: Great Horned Owl Profile

Great photos and facts.

Nature Works: Great Horned Owl

Good Article on the Great Horned Owl.

Orange County Zoo: Great Horned Owl

Short article. Fun page--Great Horned Owl sounds when you bring page up.

Oregon Zoo: Great Horned Owl

Good article.

The Owl Pages: Great Horned Owl

Good information and lots of sounds.

USGS: Great Horned Owl

Short, but good.

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Katie said...

I live right on the Irvine / Newport Beach border and have recently noticed a Great Horned Owl living in some trees a few yards away from our house. I've enjoyed checking on him throughout the day (morning and late afternoon) but recently some abnoxious crows have been harrassing him. I'm a little worried that they're going to hurt him - are they a natural predator? I'm mainly concerned because of their numbers and how close they get to him!!

Orange County Birder Girl said...

Crows often mob owls and other raptors like Red-tailed Hawks to protect their territory and young. A Great Horned Owl is the stronger of the two species by far. While it is conceivable that a large group of crows might succeed in harming an owl, it is unlikely that they would seriously try it since the Great Horned Owl is so much more powerful, and they know it.

Mark said...

Another great post OC Birder Girl! I'm working my way around OC photographing rare birds. Last night I saw a guy throwing rocks up at some great horned owls in what looks like an attempt to catch them in flight. When I walked up and called him out on it, he got super aggressive and started going off, I'm not sure what I can do about it, but I ended up walking away and coming back 15 minutes later and the owls were gone. I managed to get a photo of the idiot.

Orange County Birder Girl said...

Mark, thank you for your kind words. People who are cruel to animals usually extend their callousness to people as well. And entitled people usually react with aggressive hostility as well--as I know from experience. I no longer confront people while out birding alone. If this were done while a Great Horned Owl was nesting, it would be a violation of the federal Migratory Bird Treaty Act. They nest in the winter, but it could still be a violation of local laws. Possibly cruelty to animals. Or harassment of wildlife. You might consider calling or going in for an informal chat with the local police to see if any laws were broken and if there is anything they can do. Sea and Sage Audubon may have more ideas. Or California Fish and Game Department or the US Fish and Wildlife Service. Hope this helps. Good luck with your photographs! OC Birder Girl