Whooping Crane Migration Update: March 20, 1997

Claudia Fonkert, Macalester College

After Tom Stehn's News Flash of March 11th, there's no migration news to report on this first day of spring. While we wait for Tom to announce the cranes' departure from their winter home on the Texas Gulf Coast, let's turn our attention to conditions at the whooping crane nesting grounds in Northern Canada. Tom expects the cranes to leave soon. When will their northern habitat be ready for them?

As it happens, the caribou we're tracking this spring by satellite telemetry are quite near Wood Buffalo National Park. We've watched these poor creatures roam around on all fours in temperatures far below zero. They have not escaped winter as their winged neighbors have. While the cranes feasted on crab dinner at the seashore, the caribou were pawing through snow for a few bites of lichen in almost constant darkness. The spring equinox marks an important turning point: From this day forward, northern regions will have more daylight than areas to the south. The boreal foodchain is about to spring to life and whooping crane will soon be part of it.

Challenge Question # 2
"What is the temperature today at Wood Buffalo National Park, were caribou are currently roaming? Do you think the ice has melted yet from the marshes where the whooping cranes will nest?"

To respond to this Challenge Question please follow the instructions at the end of this report.

Weather map ready? When the migration begins, keep your eye on the skies of the Central Plains. You'll need copies of daily weather maps to accompany the weather summaries we will provide. Download a map from the Internet, or keep a copy of the weather map in your daily newspaper.

Cranes on the Rise
In our March 6th update we provided whooping population figures and asked Challenge Question # 1: "During which decade did the population grow at the fastest rate?

"The answer is," says Tom Stehn, "the 1980's. The population increased 92% during that time period. The next highest growth rates were 70% in the 1970's and 55% in the 1940's. So far in the 1990's, the population has increased only 9 %.

"I really don't know why the growth rate was the highest in the 1980's and may have experienced a downturn since then. In the early years, there were so few pairs that there was very little chance for numbers to build up substantially. Remember, whooping cranes normally raise only one chick per year, and many years the chick doesn't survive. Once the number of nesting pairs increased above 20 in the 1980's, and now is about 45, the number of chicks produced annually can potentially be high. In 1995, the population increased by a record 25 birds! But growth rates have to do with percent changes in the population. The wild population has increased by about 4% every year. Some computer models predict there may be as many as 500 whooping cranes by the year 2025. I think I'll look forward to the day I count 200 whooping cranes at Aransas. A population of 500 seems like too big of a stretch right now."

Thanks to Samantha, Keat, Tair Moalam, Shannon O'Connor, & Pam Meka in Iselin, New Jersey for answering this question--and for raising a topic for future discussion. As you'll read below, "adoptive" crane parents have helped increase whooping crane numbers. We must clarify that the population figures we provided included ONLY those cranes in the wild flock. There are other populations, such as one referred to in the students' answer. We'll provide more about this later. Here's what the Iselin Middle School students had to say:

"The Whooping Crane's population increased at the fastest rate in the 1980s. Between 1980 and 1990 they increased by 70 birds. Immense scrutiny by devoted veterinarians, the preservation of nesting grounds, and the help of the Sandhill Crane have helped the Whooping Cranes population to increase. The Sandhill Crane has helped the Whooping Crane by raising the baby Whooping Cranes placed in the Sandhill Cranes' nests by devoted veterinarians, who hoped that by doing this the Whooping Crane would be saved. The raising of these foster babies has been successful in increasing the population of the Whooping Crane." (ims@gorgon.com)

How to Respond to Journey North Whooping Challenge Question # 2

1. Address an e-mail message to: jn-challenge-crane@learner.org
2. In the Subject Line of your message write: Challenge Question # 2
3. In the body of the message, give your answer to this question:

Challenge Question # 2
"What is the temperature today at Wood Buffalo National Park, were caribou are currently roaming? Do you think the ice has melted yet from the marshes where the whooping cranes will nest?"

Don't Forget!
Please include the name of your school and your location so we can credit you properly for your answers.

The Next Whooping Crane Migration Update Will be Posted on April 3, 1997.