Signs of Spring Update: January 31, 2000 Today's Report Includes: Whoooo's Finding Romance in the Cold of Winter? The Great Horned Owl Keeps a Warm Nest Warm Eggs in the Cold: Challenge Question #1 Why Lay an Egg in February?!: Challenge Question #2 Owls Call to Find Mates Whooooo's Finding Romance in the Cold of Winter? North American humans celebrate our most romantic holiday, Valentine's Day, in the dead of winter. Few North American birds are thinking about the birds and the bees--they're too caught up in surviving the winter. But one group of birds finds February the most romantic month of all--owls. The Great Horned Owl Keeps a Warm Nest Great Horned Owl Photo courtesy of Marshall Iliff. The most widespread, common owl on the continent is the Great Horned Owl. This hardy species can not only survive temperatures close to forty below zero--it can sit in that frigid air while incubating eggs, keeping them a toasty 37 degrees C! A healthy bird's body temperature fluctuates more than ours does, but a Great Horned Owl's body temperature in Minnesota in during February has been recorded from 37.5 to 40.4 degrees C. The owl's abundant, thick body feathers allow her to share her warmth with the eggs while keeping the frigid outside air out. Of course, her body is warming the eggs from above. But their nest is in an unheated tree. What protects the eggs from icy temperatures below? Challenge Question #1 "How do owl eggs keep their heat while sitting in an unheated nest?" (To respond to this question, please follow the instructions below.) Why Lay and Egg in February!? It's interesting that owls can successfully hatch eggs in such a cold season, but the big question is, WHY? Why would any bird even think about laying eggs in February? And that is ... Challenge Question #2 "What are some reasons why North American owls might breed in mid and late winter?" (To respond to this question, please follow the instructions below.) Owls Call to Find Mates Fun Facts About Owls For owls to lay eggs in February and March, they must first find a mate. Normally owls are solitary birds, and the way they attract a mate from a distance is by hooting. Both males and females call to one another. Great Horned Owls have a variety of calls, so complex that ornithologists don't really understand the meanings of most of them. But they have determined that most male calls are deeper, richer, and longer than female calls. Listen to the hoot of two Great Horned Owls. (Wait for download, 404K file.) This is the snapping call Great Horned Owls might make when they land right near eachother. If you listen carefully, you might hear it snapping its bill. (Wait for download, 246K file.) This is the warning call Great Horned Owl parents make when a potential predator approaches their nest or fledglings. What might have caused them to make this particular call? (Answer: Lang Elliot with his tape recorder!) (Wait for download, 297K file) All recordings courtesy of Lang Elliot A lot of Great Horned Owl calls are easy for humans to imitate. Can you hoot like a Great Horned Owl? With practice, you might be able to call a Great Horned Owl in so you can see it! This works best at nighttime. A good book to read about a father and daughter going out calling for owls is "Owl Moon," by Jane Yolen. In daytime, you are not likely to hear owls, and it's hard to see them camouflaged against tree trunks, hiding in the shadows. But one bird searches out owls and when it finds them, it's mobbing caws can be heard for a long distance. If you hear ANGRY-sounding crows, check it out! There may be an owl closer than you think! How to Respond to Today's Challenge Questions: Please answer ONLY ONE question in each e-mail message! 1. Address an E-mail message to: jn-challenge-spring@learner.org 2. IMPORTANT: In the Subject Line of your message write: Challenge Question # 1 (OR # 2) 3. In the body of the EACH message, give your answer to ONE of the questions above. The Next "Signs of Spring" Will be Posted on February 14, 2000 Copyright 2000 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to jn-help@learner.org