Nesting Season for Owls

Get to Know the Habits of Barred and Great Horned Owls!

March 27, 2019
Owlet

Nesting Barred Owlet

Anne Marie Warren

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Have you heard the owls? With spring’s arrival, the Great Horned Owl and the Barred Owl are already well into their domestic responsibilities. Owls are among the first to begin building nests, incubating eggs, and feeding young. 

Identifying the Owls

Both the Barred Owl and the Great Horned Owl select nest sites in late winter. Males generally find a territory in late autumn and a nest site in February. Mated pairs remain in the same territory all year, and the hooting of both species starts occurring more heavily in March, if not before.

Keep in mind: When owls are nesting, they’re very territorial. If an owl swoops down near you, they’re just focused on mating and nesting—and will chase away intruders while hooting loudly! 

  • The Great Horned Owl is very large with yellow eyes and earlike tufts. When we think of an owl, this is the image we usually conjure up because it’s the most wide-spread owl in North America. They are nocturnal and fierce predators. Ever heard their deep hooting voice? Listen to the call of the Great Horned Owl

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Image: Great Horned Owl

  • Barred Owls are smaller than the Great Horned Owl (but larger than Barn Owls) and are an attractive white-and-brown striped bird. Barred Owls tend to hunt during daylight hours in February and March, seeking prey for incubating females. Early in the morning and at night, you may recognize their classic call, “Who cooks for you?”

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Image: Barred Owl

Try imitating the call with your own voice and then wait quietly. If you’re lucky, a Barred Owl will fly in to investigate you.

Oddly enough, the Great Horned Owl is the most serious predatory threat to the Barred Owl. Although the two species often live in the same areas, a Barred Owl will move to another part of its territory when a Great Horned Owl is nearby.

Owl Nesting

Both species tend not to build their own nests. Instead, they will spruce up an old nest made by another animal. Nests are lined with bark, feathers, animal fur, and leaves, but by the end of the nesting season, the nest deteriorates to a few sticks.

  • The Great Horned Owl uses tree nests of other birds such as hawks, crows, squirrels, and Great Blue Herons, but will also use tree cavities, snags of broken trees and wood platforms, and occasionally a building or barn. The most commonly used nest is that of the Red-tailed Hawk. 
  • Barred Owls often use natural cavities in trees, about 20 to 40 feet high. They may also use stick platform nests built by other animals (including hawks, crows, ravens, and squirrels), as well as human-made nest boxes.

Both owl species often take up residence in specially-designed nest boxes. Consider putting up a nest box to attract a breeding pair. Make sure you put it up well before breeding season (late winter/early spring). Attach a guard to keep predators from raiding eggs and young.

Laying Eggs

For both owls, 2 to 3 eggs are the normal clutch and are laid 2 to 4 days apart. The eggs hatch in about 33 days. The female incubates the eggs while the male brings food to her at the nest. In the case of the Great Horned Owl, skunk is a favorite food, so it is not unusual to smell the scent of a skunk at this time of year near a nest. Mice and smaller birds are preferred by the Barred Owl.

In years of low mouse or squirrel populations, many eggs do not hatch and many young do not survive. 

About every third year, females decide that motherhood requires a rest and do not lay eggs. Females can incubate eggs in temperatures as low as -35°F (-37°C) and eggs have been known to survive at -25°F (-31°C) for up to 20 minutes while the female takes a break from incubation duties!

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Owlets

Young birds rapidly increase their weight from 35 grams at birth (0.77 lbs.) to 1000 grams (2.2 lbs.) for females and 800 grams (1.76 lbs.) for males in less than a month (25 days). They leave the nest in about 40 days. 

While still in the nest, the mother owl will tear food into small pieces and feed it to the owlets. Thankfully, if an adult owl dies, the remaining adult can successfully raise the young. At 7 weeks, young owls are already capable of short flights. 

By late October and November, urged by the adults, young owls leave their natal territory and venture off to start their own lives!

Find even more Fascinating Facts About Owls.

About This Blog

Tom Warren has had an interest in birds since the age of 3, when he lived across from the President of the Massachusetts Audubon Society, who showed Tom how to care for injured birds. Later, a neighboring grandmother taught him the songs of warblers and thrushes, and in the eighth grade, his Middle School biology teacher took his class on birding excursions every weekend. Tom has guided bird walks and owl prowls for conservation groups, and has also participated in annual Christmas Bird Counts and the Hawk Watch on Pack Monadnock Mountain. Throughout the years, he has spent time at Pt. Pelee in Ontario observing the spring migration and has traveled to a variety of other migration areas. Tom is also committed to protecting birds and their habitat as a Trustee for both Massachusetts and New Hampshire Audubon, and the Harris Nature Center.

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