Crane Migration Update: April 8, 2005
All Chicks But One are Back in Wisconsin!
How are the "experienced" members of the flock doing? Fifteen older ultra-cranes are also home in Wisconsin: 101, 202, 209, 203, 218, 205, 211, 212, 217, 303, 312, 316, 317, 102 and 208. We’ve had no further reports for either #107 (last reported at Horicon NWR in Wisconsin on March 14) or #106 (last reported at Hiwassee State Wildlife Refuge, Meigs Co., TN on March 7). Cranes (#301, 309, 318), who spent the winter in North Carolina, were seen Wednesday in western New York, just across the Pennsylvania border! They apparently followed the Lake Michigan lakeshore NE. Where will they end up? Stay tuned, and check their flock charts:
Whooping Cranes are normally reluctant to fly at night. But on April 3 Group 2 flew nearly 13 hours with the final 3 hours in darkness! Given #412’s history, Journey North Whooping Crane Expert Laura Erickson wasn't very surprised; she remembered Nov. 26, Day 48 of the bird’s journey south. Following the ultralight, one bird broke away as the flock left their stopover in Tennessee and crossed into Georgia. The runaway was chick #412. He ended up continuing south, past Atlanta, then north. Five people tracked runaway #412 for most of the day. They finally found him roosting only 8 miles from where the migration had departed from that same morning!
Western Flock on the Move: Challenge Question #9
“The whooping crane migration is underway with an estimated 61 cranes having departed the wintering grounds at Aransas National Wildlife Refuge,” reports Tom Stehn from Texas. The excitement begins! Tom tells us that whooping cranes travel in small groups, often in groups of 5 or fewer. Single cranes sometimes even make the migration by themselves. Tom has this new challenge question for you; please send us your answers!
Try This! Log the Main Flock’s Spring Departure
A Reminder: The Aransas/Wood Buffalo flock is the only naturally occurring wild migratory population of whoopers in the whole world, and this entire flock was down to only 15 birds in 1941. That means every whooper alive today is a descendent of those 15. In other words, every whooper alive today either hatched at the Canadian nesting grounds OR is a descendant of a whooper that hatched there. Now that main flock is beginning the journey north to their nesting grounds. They’ve flown this route for centuries. Be scientists and keep track of the flock’s spring departures with Tom’s census reports, coming weekly in April, and a Log Sheet to download and print:
Whoopers Are Weather Wise
Tom reminds us, “In a typical year, most adult pairs don't leave for Canada until the second week in April, give or take a few days. However, last spring the migration was on the early side; nearly one-third of the flock gone from Aransas by April 2.” What are they waiting for?
Along Nebraska’s Platte River and the Central flyway, Martha Tacha is watching and sending us news. The weather is always a big factor in migration, as you’ll see in Martha’s field notes, next.
Cranes in the Central Flyway!
Signals From the Sky: About Those PTTs
2004 journey north is the third year that satellite data
has ever been
available for whooping
Prior to 2001,
whooping cranes had
not migrated over the
eastern portion of North America
in more than a century.
The trackers mainly rely on the radio signals
(see April 1 report for
lesson link), but on April 6, it was
PTT data that
helped trackers figure
7 was after the birds
split off from the group
In the best migration conditions, cranes can use their large wings to soar on columns of warm rising air called thermals. Thermals are created as the sun warms the earth’s surface. Soaring on thermals allows cranes to stay aloft for longer periods of time without spending energy to keep flap their wings. Learn more about thermals, and how cranes fly with these fascinating lessons:
Dancing With the Cranes: Video Clip, Story, and Teacher Tip
It’s a rare thing to hear or see a whooping crane, but video clips make it possible. In this video by Heather Ray, a pair of whooping cranes shows you their dance. See the clip and find out three reasons why cranes dance. Then read the fascinating story of a whooping crane that would ONLY dance with a very special human--now a world-famous crane authority.
Crane Speed: Answer to Challenge Question #5
Question #5 asked: “On March 30, the group
of 11 flew for 11.5 hours. They covered 450 miles.
At what average speed (miles per hour) did the cranes
Four Differences: Discussion of Challenge Question #6
Last time we asked you to read Tom Stehn’s full report and answer: “What are at least four differences between sandhill cranes and whooping cranes?”
Sandhills migrate at least two weeks earlier than whooping cranes. Sandhill cranes spend several days on the staging grounds along the Platte River in order to choose a mate, while whoopers don’t need the mass of cranes at a staging area in order to form pair bonds. Their migrations stopovers are brief, and they push north as soon as weather is favorable. Sandhills may change mates each nesting season, while whooping cranes generally mate for life. Sandhill cranes are smaller than whooping cranes, and gray-brown in color. Did you think of other differences as well?
A New Average: Response to Challenge Question #7
“ How many days was the 2004 flock on the wintering grounds before departing on their first journey north? Using this number, what is the average number of days on the wintering grounds in the 4-year history of the Eastern flock?”
How to Respond to Today's Challenge Questions:
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