Survival of the owlestPosted on March 10th, 2011 7 comments Add a comment >>
The phrase “survival of the fittest” that we associate with Charles Darwin’s Theory of Evolution, is playing out in real time this late winter season in the Adirondacks.
One of my students in ornithology lab told me of finding two dead barred owls under a tree recently, and also of a dead barred owl on the side of a NY State highway.
Today I received a call from friends saying they know of a recently deceased barred owl in their neighborhood, and about 6 hours later I hear reports of a barred owl feeding on chickens in a village residents’ backyard!
Hmm, I’m sensing a pattern here. And that pattern is lack of food, too much snow, and a poor winter for rodent populations.
Reports are coming in daily about barred owls staking out tree branches in many northeast US backyards and keeping a sharp eye on the ground under bird feeders. Here they’re hoping to catch a mouse that runs out from the snow cover to grab a few fallen sunflower seeds.
Speaking of snow cover…we’ve got plenty of it here in the Adirondacks and it’s getting hard for an owl to find their preferred food which is snug under 3 feet of snow. Owls will pounce on a mouse or vole if it comes to the surface of the snow but some recent thawing and re-freezing has left a solid layer of frozen snow/ice that a vole finds hard to get through.
In addition to hard conditions(heavy snows) for mice, we also hear that it’s been a bad season for reproduction in rodent populations. So owls face a double whammy of cold temps/heavy snow and too little food source. All the fixings for starvation.
I was recently given a dead barred owl to take into ornithology lab where our students can investigate this truly beautiful bird of prey, and if possible, prepare this owl as a museum specimen so future students can learn from it.
Before the bird went into the freezer for safe keeping, I was able to snap a few photos of it to show the details of why it’s known as a bird of prey.
Talons for catching a rodent:
Tiny extensions on their primary(wing) feathers for turbulence reduction-which allows for silent flight:
Pretty sharp beak for tearing flesh:
Well, the spring forecast calls for rain, warming temps, and a growing litter of mice:-)
Photo Credits: Barred Owl(top)-Wikipedia, all other photos by Brian McAllister
There is an interesting mixture of both correct and misleading information in these comments. Here is my two cents.
I have to agree with Mike and with the moderator of owlpages.com; large owls do just fine busting through deep snow and even ice layers when hunting mice. (Ive written a published paper on this subject.)
But Mike is incorrect in referring to Great-horned Owls with the implicit assumption that their catholic diet is similer at Barred Owls; it is not. Barred owls, like Great Gray Owls, primarily eat small mammals in the north country in winter. This winter, and every winter when the mouse populations are low, Barred Owls are forced (by hunger) to hunt more during the day and to visit feeders and roadsides where rodents are more abundant and/or easier to find. Barred owls are ARE FOOD STRESSED in the Adirondacks this winter. This is the second winter in a row with no cone crop, an unusual event in recent decades in the Adirondacks as the climate warms (cone crops typically have been a binannual event in the past 2-3 decades). Mouse (and conifer-seed eating finch and nuthatch) populations are severely depressed in the Adirondacks compared to when there is a conifer seed crop (as there will undoubtedly be this coming winter).
So, I agree with Brian except that I think the snow pack has nothing to do with Barred Owls appearing more along roadsides, and thus being more prone to vehicle collisions.
Come on guys. Don’t you think birdfeeders and roads are just a place to get any easy meal without extending alot of energy. If owls are smart like you said that would be the smart move. Take in more calories than you lose, first rule of survival. oh and by the way if you hove 60′ of snow pack you probably don’t have many roads or birdfeeders for that matter
Car impacts with Barred Owls along the road are common everywhere in the United States. What is happening in the Adirondacks is nothing new or different from other areas. A number of years ago a sleepy town in the Carolinas tried to restore their village with 50 barred owls. A year later almost all of them died because of car impacts. They wouldn’t be hunting on the side of the road because of the snow pack.
Barred Owls are well known to visit and even live in people’s backyards. Especially if they have a bird feeder. Bird Feeders bring in a lot of prey, so this makes houses attractive. I have hundreds of picture of Barred Owls next to and on houses from Florida to Canada. Both in the Summer and Winter. Nothing new there. Virtually all species of birds are on the Barred Owl menu. A bird feeder just increase the population for them. It is not unusual for Barred Owls, as well as other owls, to pick off song birds just as they are settling in for the night. But, this doesn’t stopped Barred Owls from picking off a song bird in the afternoon.
Chicken coops get visited by Barred Owls and Great-Horned Owls all the time. Often times once they get in, they can’t get back out of the chicken coop. Have lots of picture of people retrieve the owl out of their chicken coop, but not before it takes one of the chickens.
A gradual increase in the snow pack doesn’t affect the rodent population that much. A very large snow storm can keep rodents down under the snow. Last year, the Catskill Mtns received 7-8′ of snow in one storm on top of the existing snow pack. This kept the rodents down under the snow for 3-4 weeks. Rabbits were kept down for 2 weeks. The Barred Owls population was not affected at all. Barred Owls actually flourished because other ground predators were seriously affected by the snow. Even if all the mice, voles, minks, possums, rabbits, squirrels, and chipmunks died Barred Owls could easily live off just song birds.
Snowy Whites and Great-Gray Owls have very limited menus, and their population goes up-and-down with the prey population. Barred Owls, Great-Horned Owls, and Screech Owls, are not affected by changes in populations of a couple prey items on their menu. When watermelons and cantaloupes go out of season, the human population is affected. Same thing with Barred Owls. What can affect the Barred owl population is diseases in prey animals. Another items that can significantly affect owls within a small region is rat poison. This has devastating affect on owls. In the long run, it just increases the rodent population.
I am the moderator of Owlpages forum and a researcher of owls for the past 40 years. I am sure that the snow pack in the Adirondacks has little or nothing to do with the death of barred owls there. The snow pack really isn’t that deep this year when compared to other parts of the US where Barred Owls live. Barred Owls live from the east coast to the west coast. In some of those areas the snow pack can be up to 60 feet deep, and barred owls in those areas have no problem finding food. They are an adaptable owls, which can quickly shift to other prey on their menu. They do have an extensive menu of prey.
Having spent time in the Adirondacks for the past 45 years, I can assure you that there is plenty of food for them there. Barred Owls are very smart about finding prey, and because of this ability they have increased their territory dramatically over the past decades. Probably more then any other owl on earth. If for some odd reason the Adirondacks did lose all the song birds, owls, mice, voles, squirrels, rabbits, skunks, possums, etc, Barred Owls are known to move up to 150 miles from their nesting site. They would just fly to other areas.
A more likely cause would be disease. Owls are more prone to contract intestinal disease from prey. When they do contract one of the many intestinal disease, they will stop eating until they get better or die.
Dead Barred Owls along the sides of the road are almost always caused by car impacts. It is one of the leading cause of deaths of owls.
Sorry Mike, but I have to agree with Brian. This winter has been exceptionally hard on barred owls. Between the snowpack & the heavy snowcrust, the owls weren’t able to hunt mice. I had a barred owl in my back yard for over a week (never left), looking for anything he could “pick off” around the bird feeder. I finally threw some dead squirrels on my lean to roof and every morning, they were gone.
This is not the first time I have had a barred owl in my yard. Some years ago, during another hard winter, a barred owl died on my bird feeder.
Good artice Brian!!
Maybe you should have done some research before writing this article. The information in it is patently false.
Snow pack has little to due with their survival. Owls are at the top of the food chain. When all other animals have died, owls will still be there. For example, Great-Horned Owls have a menu of 255+ animals to prey on. They can take prey up to 3 times their body weight. So, skunks, foxes, cats, dogs are on their menu. Owls will even eat other owls. They are cleaver, crafty and smart when it comes to finding food. If you still question this, then you have to answer why there are so many owls in Canada/Alaska when compared to the United States. The claims in the article are ridiculous.
You should have at least referred to the worlds leading site on owls: owlpages.com or people like Denver Holt, Clark, Johnson, or Tania J.
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