Saturday, April 25, 2009

Camera Critters: Life of a Great Horned Owl

I have been fortunate, over the past few years, to have the opportunity to observe the day to day behavior of great horned owls. Since they are crepuscular, meaning that they are most active at dusk and dawn, they re often difficult to find in the wild, even though they are quite common through out most of North America.

great horned owl in nestThe best time to see great horned owls is during the nesting season. Mating usually begins in January or February. Courtship usually begins with an intimate conversation between prospective mates that can often be heard from a great distance. This is followed by a little foreplay, the birds rub their beaks together and preen each other, and then it is time to find a nest. Great horned owls do not build their own nest they borrow someone else's, usually a hawk, crow, heron or squirrels. Once the eggs are laid the female stays on the nest night and day and incubates them.

great horned owl While the female great horned owl sits on the nest incubating her clutch of 1 to 5 eggs the male spends his days perched near by. When perched the pattern of the feathers on the stomach and chest help it to blend in and camouflage itself next to a tree trunk. This is helpful because any hawks that spotted the owl resting during the day would most likely attack it. Crows also pose a problem during the day. The owls have very little to fear physically from the crows but if spotted the crows will usually mob the owl. This means that they will dive and squawk at the owls which will alert any prey or other predators in the area. Crows are the best way to find owls when it is not nesting season, just follow their racket.

great horned owl The males job is to bring home the bacon, or in this case mouse, rat, squirrel, rabbit, skunk, bird or other prey species, of which there are at least 250 different types identified. They are ambush hunters, meaning that they perch on a branch or snag until they see or hear some prey below then they swoop down silently killing the prey with their talons.

great horned owlLike all raptors, great horned owls swallow their food, it's tough to chew if you don't have teeth. If the prey is small enough they will eat it whole but if it is larger, the preferred food of great horns is rabbit, then the owl will use its talons to hold the food and grab it with its curved beak, pulling back with its strong neck muscles to rip the meat into bite size pieces. They will usually eat everything, even though they can not digest bones, fur or feathers. Six to ten hours after eating the owl will regurgitate the indigestible material in the form of an owl pellet.

great horned owl chicks in nest After 26 to 35 days the eggs finally hatch. The young owl chicks are covered in white down feathers. At this point the female may leave the nest for a short period of time however she stays close so that she can protect the helpless chicks and help to keep them warm, especially in Minnesota where the eggs can hatch in February when the temps are often below zero.

great horned owl chicks in nestEach night or morning the adults deposit food that they have caught into the nest. As the chicks have gotten larger mom spends less time at the nest. She still comes back to feed the young ones who do not yet have the strength to rip prey into bite size pieces.

great horned owl chicks in nest As they get older the chicks down feathers are replaced by adult feathers and they begin to more closely resemble great horned owls and look less like Ewoks. As they get larger and take up more room in the nest mom spends more time away from home, often stopping by only for meals. At 6 to 7 weeks the young owls get antsy and begin to leave the nest to climb and explore neighboring branches. At this point they are referred to as branchers, however they still will not be able to fly for a few more weeks, at about 9 to 10 weeks. Once they are able to fly the adults will continue to feed them for a few more weeks while they learn to hunt on their own. Once they have been weaned off of relying on mom and dad for food the young owls will continue to stay around the nesting territory for the remainder of the summer then come fall they will set off on their own.

great horned owl chicks in nestAll of these pictures were taken at a nest in Lakeville, MN this year. I first photographed the female on the nest on January 31st. While she was on the nest I was frequently able to find the male, who is featured in the second, third and fourth pics, in the woods nearby. The first picture of the chicks was taken on March 28th. They were probably born near the beginning of March but since the nest is fairly deep they could not be seen until they got a little bigger. The last three pics were taken on April 23rd. You can see that much of their down is gone. If they are not already branching, they did not on my last visit, then they will be soon. You can tell that one of the chicks looks a little bit larger and more developed. This chick is more likely the older of the two.


19 comments:

DrowseyMonkey said...

Oh wow! These are amazing photos! And I've never heard of this type of owl before ... very interesting.

Manz said...

You're posts never fail to be interesting.

I paticularly like the nest photos in this series.

*****
On another note, I've set up a "directory" page on the main gritfx website for my cc posts. I'd like to add some links to other cc participants - yourself included. If you're interested in being added, send me a website/blog badge (120pixels wide x 80pixels) to manz76@live.com.
Manz's Camera Critters Page

Chris said...

Magnificent. I love the second one where it's playing hide and seek with you!

LadyBanana said...

Very interesting - lovely owl..

Richard said...

Great series of photos and the education to go along.

Abe Lincoln said...

These are all individual excellent photos. An excellent series too.

Adirondackcountrygal said...

Great photos!

madcobug said...

Very good pictures and an interesting story added to them. They do a good job of blending in with those trees. Helen

Karen said...

Wonderful photos..

I like all the information as well, thankyou :-)

Sue said...

These are great, Jeff. Thanks!!
sue in lakeville

Adrienne in Ohio said...

Always beautiful and informative, your posts are such a treat to read. My daughter and I found an owl pellet in our backyard a couple of months ago under one of our large beech trees. We've never see the owl, but we do find evidence that one has been here occasionally. What fun it must have been to discover the nesting pair and return to photograph the owlets!

Miss Figueroa said...

Are the hatchlings often born at different times? you said one of the hatchlings was older than the other.

Babooshka said...

This is new to me too. Just how intense is that stare.

Pam said...

I drive by the same nest on my to and from work everyday. It has been fun to try to spot the adults and the babies in the nest.

Thrifty Living Mom said...

THANK YOU SO VERY MUCH for the beautiful pictures and thorough description. We have heard the Great Horned Owl outside our windows during the months of January-February for the past several years, but have never, ever seen them. My children and I would wake each other up to say, hear the owl? It's back! We just love to hear them hoot back and forth to each other. Thanks again!

The Explorer said...

they are all cute, and i just noticed that they like to be your model, i like them all.

Anonymous said...

I visited your site seeking information that might explain the unusual behavior I witnessed a few days ago at twilight. I heard two distinctly different great horned owl calls from opposite sides of my 3 acre back yard (lots of mature hardwood trees.) I went out to see if I might visually locate the bird/s and saw one in the SE corner of the yard. Within moments, a second great horned owl swooped down near the ground and then up to land on the same branch as the first slightly larger owl with deeper call.
I watched them for about five minutes. They continued to make their respective calls and moved toward each other and then away - but as they called, the bird bobbed its head up and down and lifted the tail feathers to about 45 degrees from the body. After about five minutes of this behavior, the smaller, higher pitched owl took off toward the SW again. Can you explain what was going on?

Indigo Swallow said...

Hey there,

This post was truly informative and intriguing, I attached two images of the owls you took to my own blog and linked them back here. I sure hope that was okay, and you do not mind in the least... I was hoping to capture my own owls at home this morning yet when I went to go see if they had returned yet I was let down... so then I found you... and your work to boot!

http://spiritoftheprairie.blogspot.com/2010/12/awaiting.html

See you in the wind,
Michaela Dawn

Anonymous said...

I have a pair living right across the street but have yet to locate a nest...