Ruler of the Night—The Great Horned Owl

Tweets & Tree Frogs is participating this the 2015 PNW Nature Blog Scavenger Hunt. For more details, click on the logo.

Tweets & Tree Frogs is participating this the 2015 PNW Nature Blog Scavenger Hunt. For more details, click on the logo.

by Bob Tuck

Urban residents are sometimes startled by the sight of a large, dark bird silently gliding across a moon-lite residential street. How, they may wonder, does such a large bird find a place to live among houses, schools, businesses, and other human structures?

Great horned owl

Photo credit: Bob Tuck

The great horned owl (Bubo virginianus) is one of the largest owls in North America, and one of the widest distributed bird species in the world. From the treeline in northern Alaska and Canada, coast to coast south to Central America, and then further south throughout South America down to Tierra del Fuego. Other members of the genus Bubo are found worldwide, except for Australia and islands in the Southwest Pacific.

These large raptors stand almost 2 feet tall and have a wingspan of nearly four feet. They are more common in urban areas than many people realize. Any park or open area with large conifers where they can roost out of sight during the day may well harbor a pair. I have heard the familiar, deep voice in urban Vancouver, WA, for example.

The key to this wide distribution is their versatility. Great horned owls do not build their own nests. Instead, they use what is available in their area. In rural areas, they commonly nest in the abandoned nests of other large raptors, such as red-tailed hawks, or crows and ravens. They also nest on cliff ledges, the broken tops of large trees, or large tree cavities. In urban areas, they nest in old crow nest, ledges on large buildings, in lofts or attics, or any place that provides seclusion and protection for their 2-4 eggs.

These large predators also make use of a wide variety of prey, which also contributes to their use of many habitats. They can take large prey, such as skunks, jackrabbits, pheasants, opossums, or other medium-sized birds and mammals. They also can make use of smaller prey such as mice, rats, gophers, squirrels, bats, snakes, frogs, fish, and large insects. In urban areas, their prey is largely mice and rats, frogs, large insects, and birds such as sparrows, starlings, and pigeons. Given the large numbers of rodents and several species of birds in urban areas, it is not hard to understand how great horned owls may find such areas inviting places to call home.

Even if you don’t hear or see them, you may find their large pellets on the ground beneath their roost or other prominent perch. Like other raptors, owls swallow their prey whole or in large pieces—bones, hair, teeth and all. Within 24 hours, these indigestible parts are formed into oblong-shaped pellets with the fur and hair on the outside and bones and teeth in the center, and then “cast,” or regurgitated. Pellets provide a record of the prey consumed by the owls and are an invaluable source of information for wildlife biologists.

Even though you may live in an urban area, many species of interesting wildlife call your neighborhood home. These large owls are one of the most interesting.

Great Horned Owl Books and Resources

Groundhog Day 2015–Books, Activities, Fun!

Yellow-bellied marmot lounging at Yellowstone NP. Groundhogs are a species of marmot.

Yellow-bellied marmot lounging at Yellowstone NP. Groundhogs are a species of marmot.

Groundhog Day is my favorite holiday. There are no expectations. No rituals that must be observed. No cards to send. No gifts to buy. Just an adorably furry animal prognosticator and whatever celebrations we can muster on the actual day.


Just in case you feel like celebrating too, here are my favorite Groundhog Day picture books. Click book images to link to the book at IndieBound.

Brownie Groundhog and the February Fox, by Susan Blackaby, illustrated by Carmen Segovia (2011 Sterling Publishing Co., Inc.)

This adorable tale from one of my favorite Oregon writers stars a plump, intelligent groundhog, Brownie, who must outsmart the February Fox to avoid becoming lunch. The illustrations are so fun, that I’ll forgive the illustrator for depicting a European robin with a North American groundhog. (The illustrator is from Spain, home of the original robin–smile.)

Go to Sleep Groundhog, by Judy Cox, illustrated by Paul Meisel (2004 Holiday House)

This is a fun book from another Oregon author! Poor groundhog is suffering from insomnia and gets help from some other holiday icons. It’s cute and funny and is a great bedtime read.

Groundhog Weather School, by Joan Holub, illustrated by Kristin Sorra (2009 G.P. Putnam’s Sons)

After the official groundhog gets a complaint that his forecast was not helpful because it is too far away, he recruits other animal prognosticators to help him out. The recruits go through the paces at Groundhog Weather School in preparation for the big day. Holub has crafted a fun story that is packed full of factual information about weather and groundhogs. Does sharing the load make the predictions more accurate? You’ll have to read this one to find out.

Groundhog Day! written and illustrated by Gail Gibbons (2007 Holiday House)

Gail Gibbons is one of the most prolific nonfiction picture book authors out there. Like all her books, this one is a nice overview of the topic. It includes information about groundhogs, the history of the holiday, and information about how Groundhog Day is celebrated today.


  • Peek-a-boo Groundhog and a Groundhog Day mask can be found here.
  • Puzzles, coloring sheets, and crafts can be found here.
  • This site has a cute groundhog and shadow craft and also a pretty cool potato stamp project.

All about Groundhogs and Groundhog Day

Winter Books

The holiday frenzy is over, and we are settling into the firm, misty grip of winter. Time for frosty walks, hot tea, and a pile of books. Here are a few of my favorite winter-themed books:

Over and Under the Snow, by Kate Messner, illustrated by Christopher Silas Neal (2011 Chronicle Books)

This picture book explores winter wildlife–foxes, owls, and deer above the snow and voles, shew, frogs and more below the snow. I really enjoy the use of the human story arc–a girl and her father enjoying a day in the snow–to bring us close to each of the animals. The muted, winter-colored illustrations have hints of woodcut and collage with splashes of red and yellow. Just a lovely book with lots of animals, beautiful pictures, and nice author notes at the end.

Under the Snow, by Melissa Stewart, illustrated by Constance R. Bergum (2009 Peachtree Publishers)

Melissa Stewart is one of my favorite nonfiction writers. Her take on the winter world explores some different creatures, including pond animals, making it a nice companion piece to Messner’s book (it stands just fine on its own as well). Bergum’s drawings are warm and lovely.

Survival at 40 Below, by Debbie S. Miller, illustrations by Jon Van Zyle (2010 Walker & Company)

This book explores the unique adaptations arctic animals employ to survive harsh winter weather. It is packed with information about animals from musk oxen to woolly bear caterpillars, actually explaining how these animals manage to survive. The realistic illustrations bring the world to life. It is much more text-heavy than the previous two books–perhaps a little much for a bedtime story, but definitely worth sharing.

“Big People” Book for January

This month I’m going to be tackling Winter World: the Ingenuity of Animal Survival, by Bernd Heinrich (2003 Harper Perennial) From the flap copy: “From flying squirrels to grizzly bears, and from torpid turtles to insects with antifreeze, the animal kingdom relies on some staggering evolutionary innovations to survive winter. . . . Winter World awakens the largely undiscovered mysteries by which nature sustains herself through winter’s harsh, cruel exigencies.” I’d love to chat with others who’ve read this book or who want to join me in reading it this month.

Happy New Year to you all. May your 2015 be filled with adventure and peace.

Frozen—the Caterpillar Version

This is a woolly bear caterpillar from my part of the country.

This is a woolly bear caterpillar from my part of the country.

A year ago, I wrote an article about frogs that have adapted to survive being frozen. Turns out these frogs are not the only creatures that have developed ways to survive extreme cold. One of my favorite cold tolerant species is the Gynaephora groenlandica (no, I can’t pronounce it either!). It’s also known as the Arctic woolly bear moth. Now I realize that most of us don’t have these creatures in our backyards, but their ability to survive harsh winters make them a fun topic to explore with kids this time of year.

Arctic woolly bear moths spend the majority of their lives in caterpillar form—fuzzy, golden-and-orange little guys about 2 inches long. In order to pupate (form a cocoon), they must reach a certain body mass. However, the short Arctic summers don’t allow them to eat enough in one season to reach this magic number.

The caterpillars solve this problem by overwintering in their larval form. Specific adaptations in their bodies, including the ability to produce antifreeze compounds in their cells, allow them to survive temperatures down to -90 degrees F. Each summer they emerge for to eat and eat and eat before spinning a hibernaculum (silk “sleeping bag”) that will house them until the following summer.

Artic woolly bear caterpillars actually spend the majority of their lives frozen! After around seven summers (and up to 14!), they build up enough food resources to pupate into an adult moth. The adult moths have a few frantic days to mate and produce the next wave of super trooper caterpillars. Then the whole cycle starts all over again!

  • Frozen Planet from Discovery had a segment on the Arctic Woolly Bear Caterpillars. You’ll find it here.
  • My article on Antifreeze Animals (wood frogs) appeared last year on the KIDS DISCOVER Teacher’s Blog. It includes a classroom activity that examines one mechanism (cryoprotectants) that these animals use to survive being frozen.
  • A woolly bear caterpillar craft from Samantha at Stir the Wonder–you can change the colors to match the Arctic woolly bear.