Announcing Journey North's 6th Annual
Internet Ice-Out Contest
for Walden Pond

Signs of Spring Update: February 14, 2000

Today's Report Includes:

Announcing the 6th Annual Ice-Out Contest for Walden Pond
When do you think the ice will melt on Walden Pond this spring? Famous naturalist Henry David Thoreau kept ice-out records in the mid-1800's and recorded them in his celebrated book, Walden.

"Standing on the snow-covered plain, as if in a pasture amid the hills, I cut my way first through a foot of snow, and then a foot of ice, and open a window under my feet, where kneeling to drink, I look down into the quiet parlor of the fishes..." Henry David Thoreau, from Walden

How to Enter the Ice-Out Contest
1. Look at the ice-out records below, kept by Thoreau for Walden Pond in the mid-1800s.

2. Calculate the average date the ice melted over the years he kept records. (Don't forget the students' recent data too.)

3. Next, read the latest news from Walden. And pay attention to the temperatures in Massachusetts over the next few weeks.

4. Finally, place your guess by responding to this question:

Challenge Question #3
"When do you predict ice-out will occur this year on Thoreau's Walden Pond?" (Please give an exact date, rather than a range of dates.)

Remember: The deadline is February 28!

You'll hear from us the day the ice goes out, so watch for the news! We'll announce names of the contest winners, too. If you don't hit Walden's ice-out date, not to worry. You'll have five more chances to predict ice-out dates at the remaining observation posts:

Ice-Out Records for Walden Pond
These are the dates the ice went out at Walden Pond as collected in the 1800s by Henry David Thoreau:
• 1845 April 1
• 1846 March 25
• 1847 April 8
• 1851 March 28
• 1853 March 23
• 1854 April 7

..... and as collected in the 1900's by Journey North students

• 1995 March 18
• 1996 March 23
• 1997 February 22
• 1998 February 26
• 1999 March 1

Walden Pond Update: What Song Does Ice Sing?
Here's the latest news from naturalist Michelle Dumas at Walden Pond State Reserve. We hope it will help you predict the 2000 ice-out date for the Pond:

"A check of ice thickness for today (February 10) ranges from 3" to 12". The range is so great due to the underground streams that feed the pond and the currents they produce. Today the temp is 40F, which is a little above normal. Overall temps have been well below normal, about 20F during the day and single digits at night.

"I rely on the ice estimates of the ice fishermen who spend most of the day trying to find where the fish are hiding. Ice total thickness has varied over the years...as little as 2" and as many as 13" (13" in 1994). If the weather remains as cold as it has been, we may reach 13" again.

"One of the best times to visit the ice on Walden is during the early morning when there is total silence except for the great creaking, cracking and thumping noises the ice on the pond makes. I have had the pleasure of listening to Walden's song many mornings and so did Thoreau. He wrote, "The pond began to boom about an hour after sunrise, when it felt the influence of the sun's rays slanted upon it from over the hills; it stretched itself and yawned like a waking man with a gradually increasing tumult, which was kept up three to four hours."

Keeping The Nest Warm: Response To Challenge Question #1
Last time we asked you how do owl eggs keep their heat while sitting in an unheated nest?

Great Horned Owls usually nest in old crow, raven, hawk, or heron nests. In most areas they line the bottom with softer material, such as shreds of bark, leaves, downy feathers from their own breast, the fur and feathers of prey animals, and trampled pellets. This material tends to insulate the nest, holding the mother's heat in. She separates the feathers on her belly, exposing bare skin called a "brood patch." This skin rests against the eggs, but her body feathers surround them on the sides, and the insulating material in the nest keeps the cold out below.

Virtually all birds, including owls, roll their eggs once or twice a day. This helps ensure that the babies all develop properly, with the whole bird warmed rather than just one side. Rolling the eggs also prevents the little developing chicks from sticking to the shell.

Why Lay Eggs in February: Response To CQ #2
What are some reasons why North American owls might breed in mid and late winter?

Owls are well-adapted for finding food in winter. So the male Great Horned Owl can usually hunt successfully to feed himself and his mate both, and when the babies hatch in March and early April, the parents will be able to find food enough for most of them. Incubation of the eggs usually takes a bit over a month, and the babies remain in the nest for about six weeks-by the time they fledge and begin learning how to hunt, there will be an abundance of inexperienced young mammals available for them to practice on.

How to Respond to Today's Challenge Question: