Birds & Birding

Osprey Cam’s Nest Is Occupied – By an Owl!

April 18, 2018

Editor’s Note: Osprey Cam has been a popular feature for five years on The Nature Conservancy’s web site. Viewers enjoy a 24/7 look at the life of nesting ospreys. This year, though, a surprise occurred. A bird was nesting, but it wasn’t an osprey! What’s going on?

David Mehlman, Director of the Conservancy’s Migratory Bird Program, shares more information on why there’s an owl on Osprey Cam.

You’re seeing things correctly. This year’s Osprey Cam nest is occupied by an owl! A Great Horned Owl has occupied the Osprey’s nest, which I personally find fascinating.

As someone who studies the geographic ranges of birds, the Great Horned Owl has always intrigued me because of its enormous range. It is found throughout the Americas, all the way from far northern Canada and Alaska, through Mexico and Central America, to very southern South America in Patagonia. And, it is found from sea level to well over 4300 meters (over 14,000 feet)!

That distribution is one of the most widespread of any native species that we have. It also has an equally large diet, eating everything from insects to medium sized mammals and large birds; having said that, about 90% of its diet is mammals. In many parts of North America, they are famed for having an inordinate fondness for skunks. To top that all off, although the Great Horned Owl, like most owls, is primarily a nocturnal predator, it is known to forage in the daytime. Nothing is safe!

Great horned owl and chicks. Photo © Scott Copeland

One unique feature of the Great Horned Owl, though, is that it does not build its own nest. This is the primary reason that we are seeing it in the Osprey’s nest – it has taken that nest over from its true owner. Most commonly, Great Horned Owls nest in nests that were actually built by other tree-nesting birds, such as hawks, crows, and ravens. If there are no trees, the Great Horned will nest on rock ledges, snags, buildings, artificial platforms, and even on the ground.

Since the Great Horned Owl is so widespread and found in so many habitats, they are somewhat nest site limited so are forced into using whatever is available to them where they are.

But, lest you think that the owls are nest thieves, there is one aspect of the Great Horned Owl’s biology that makes it likely that the owl did not “steal” the nest or displace another occupant. Great Horned Owls generally begin nesting very early in the year, often in the middle of winter.

At that time, most of the species which build the nests are many months from beginning to nest. So, Great Horned Owls are almost always either using an abandoned nest from prior years or an old nest from the previous season.

In the latter case, if the rightful owner comes back and finds an owl in its place, the nest builder can go off and easily build another nest in a nearby tree. I suspect that is what happened in this case, that the owl began to nest early, before the Osprey had returned, and that’s why the Osprey nest turned into a Great Horned Owl nest. We’ll have to wait until next year to see if the Osprey comes back or whether the owl renews its “lease.”

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12 comments

  1. GHO are also birds of habit. We had a pair that nested at our farm stead for about 20 years. They didn’t always use the same nest, but were always in the same area. They have utilized magpie, hawk and eagle nests over the years. The original couple stopped coming (we assumed they died) and about 3 years later a new couple of GHO arrived and took over a hawk’s nest. They have been returning every year since. They have absolutely no fear of us no matter how close we get to their nest. We occasionally get some great pictures.

  2. I love them and to me they used to be more common, now I see and hear a lot more Barred Owls.

  3. We had the same thing happen last year in the spring of 2017 we noted that a great horned owl was nesting in the local osprey nest! The osprey came back and looked quite puzzled but then moved a few poles down and built a kind of pathetic new nest. That year saw baby great horned owls and osprey. This year we were curious to see what happened! The owls did not come back and when the osprey did they did not go back to their original nest (which is quite nice) but went to their new nest! So far no one is in their old nest!

  4. Hello! I just watched the fledging video of Wolfie, which was brought to my attention via an email from Nature Conservancy. Can you tell me if Wolfie had siblings? Just curious as to what happened. Thank you.
    I am currently watching a Barn Owl nest courtesy of CARRIE out of Lafayette CO. In late April 2018 it is suspected that a GHO killed the male Barn. The wing was seen hanging out of the GHO nest and the male never returned. The mama Barn is caring for 5 owlets. CARRIE just started supplemental feeding. I have been watching nest cams for 3 years and the GHO seems to have gained a Bad Boy reputation. He knows what he wants and he gets it. 🙂 A very successful owl species. All the power to them I guess. Thank you for the video. Good luck Wolfie and happy hunting!

    PS. Any chance you might have a SawWhet owl cam in the future?

    1. Hi Jeannie, The owl that you see in the video did have a sibling. Sadly, the sibling was taken by an eagle. Eagles sometimes take the chicks of other species to feed their own young.

      I do not know of any plans for a SawWhet owl cam at the moment, but it is a good idea. Thank you for your interest!

  5. I have heard from docents at the World Center for Birds of Prey that falconers have a very dim view of Owls. (a real hazard to falcons) I really enjoyed seeing them fly their large European owl.

  6. This is so moving I had tears in my eyes. I want to come back as Owl

  7. I had no idea of the range of what I think is the most awesome of all owls!…Just imagining the differing habitats this owl must visit blows me away…wow, what an opportunist! From high mountains to desert, to coast, to dense woods, fields, streams and rivers. And such a diet; again very opportunistic. Great survival strategy. And what a sight they are to see hunting! How they can maneuver in dense woods also amazes me.

    We startled a Great Horned as it was waking up for dinner on the Tualatin river here in NW Oregon, west of Portland in Washington county. It was about 5:30PM on a warm July day. The bird’s nest was in a high Oregon ash tree right by the river. It was a very protected section of the river – we could not go far up or down due to big log jams, so this section of the river is rarely visited. When we startled the bird it let out a squawk of sorts and flew downstream across the river into the dark woods. I wondered how it could maneuver so silently through the immense dense tangled branches of the riparian forest. Amazing! Its short flight was both silent and majestic.

    What a bird!

  8. This is one of my favorite birds of prey! As the town I live in has grown tremendously in the last 30 years, these birds seem to have become more numerous. I’m sorry to say the barn owl population has declined a lot. Interesting how some species can adapt and others can’t .