Great Gray Owl Nest Log #5by Dan Hartman
July 19, 2022June 27th Arrived at 7:30 am. Fresh bear scat on the trail up. Also moose.
When I got to the nest, my heart sunk. The female was off the nest, perched high, making begging sounds. No sight or sound of the chicks from the nest.
I just stood there staring, not willing to accept it was over. Then I heard the female begging louder. Even though I couldn't see the chicks, I figured she wouldn't be begging so insistantly if the chicks had died.
So I waited, staring at the nest, watching for some sign of life.
I found myself kicking at the dirt, not realizing what I was doing. My mind was numb as was my body. Two and a half hours later, I gave up and hiked down.
It was really over.
This is the 24th time I have observed a great gray nest. Never before had one completely failed. I'd always gotten at least one chick to fledge. My average was two fledglings, with enough nests having three to make up for the ones who had only one survive.
I knew the nest was in trouble, but on my last visit the chicks both seemed strong and active. Chicks wouldn't both starve at the same time. It just didn't make sense.
Terrible weather, lots of competition for food, predators, especially the marten all threatened the success of the nest.
But even though the male was seldom seen bringing in food, the chicks were growing, even starting to turn gray.
What had happened?
What killed the boreal owl Gary and I found near its' nest back in late April? Why did our golden eagle chick die in our nest near Bridger, just as it begun to change form white to dark markings?
There is an on going avian flu epidemic, effecting raptors. That's a possibility.
But I don't think so.
I think the same drenching weather that closed Yellowstone with the 500 year flood, wiped out the pocket gopher population and effected the voles.
What was evident in the prey I witnessed coming to the nest. Only two gophers, when gophers are usually their main prey. I never did see a vole arrive. What I did see were mice, which are very hard for great grays to capture. Mice are quick, more suitable prey for owls like pygmy, saw-whet and even great horned. Great grays are methodical hunters and gophers more match their abilities.
Now since the chance of both chicks dying at the same time from starvation would be almost impossible, as bad as the food supply was, I don't think that's what happened. Simply because when a chick dies he is fed to the surviving chick. That would keep it alive for at least a couple more days.
Still, I think lack of food is what killed the chicks.
I had observed the female moving farther from the nest in search of prey. And I'm afraid it was during one of these hunting expeditions the marten found the nest unguarded and killed the chicks.
On previous nests the female always perched near the nest to protect it from predators. Our female was helping the male search for food because of the dire weather events. And it was working, until it didn't.
Now you can't blame the marten. She was faced with the same challenge as the female owl.
Once the marten located the nest, it was a matter of waiting for her chance to catch the nest unguarded.
So my project filming the nest from start to fledging has come to an unexpected end. Just one more set back in this unusual and trying year.
Female Great Gray Owl