Whooping Crane Migration Update: April 12, 1999
Today's Report Includes:
Crane Update Schedule Change
We're going to start posting Whooping Crane reports on Mondays to allow us to start getting more current, last-minute reports from Tom Stehn, who does his airplane surveys on Fridays.
Tom Stehn's Report from Texas
Whooping Crane biologist Tom Stehn writes from Aransas NWR in Texas:
Dear Journey North:
"Our USFWS Endangered Species office in Grand Island, Nebraska has received reports from as far north as North Dakota (probably one of the first pairs to leave Aransas around March 21). The whooping cranes migrate in very small groups and not in big flocks.
Challenge Question #6
"What might be some advantages for a species to migrate in very small groups rather than big flocks?"
(To respond to this Challenge Question, see below.)
"Although most of the flock is currently still at Aransas, many are expected to leave within the next two weeks. Although you may think that they simply are wanting to eat that last tasty blue crab seafood dinner before they go, the timing of the migration has evolved for very specific reasons. The cranes have to balance the need to get to Canada and build nests during the short summer season, but don't want to encounter severe spring blizzards on the way or have frozen ponds when they reach the Northwest Territories in Canada at the end of April or first week in May.
"Of the birds in migration, the state of Nebraska seems to be the focal point at present. Sightings around April 3 included separate groups of three, two, and two. A pair of color-banded cranes with identifying white and blue bands that had left Aransas sometime before March 25 were sighted on the Platte River in Nebraska on April 3. It normally takes the whoopers about one week to travel from Texas to Nebraska. They fly anywhere from 200-400 miles a day. However, if they encounter winds from the north, the birds choose not to migrate that day and instead will spend the day feeding in wetlands or agricultural fields. It would just take too much energy to fly with the wind in your face and not at your back.
"I expect to find about 100 cranes on my next census flight April 8, with fewer than 50 here by April 15. "
Tom Stehn Whooping Crane Coordinator
Challenge Question #7
"What is your prediction of how many Whooping Cranes Tom Stehn counted on his flight on April 8? And when do you predict that the first whoopers will arrive in Wood Buffalo National Park?"
Wally Jobman's Report from Nebraska
Whew! Tornados ripped through parts of Nebraska last week, but Wally Jobman assured us that he and the cranes were fine. He writes,
April 9, 1999
"Weather during the past week was unsettled with periods of rain and strong wind. Winds were from the south on 4/4, 4/6, 4/7, and 4/8, and sandhill cranes were observed migrating on each of those days. Severe weather with several tornados occurred in eastern Nebraska on 4/8. The severe weather was all east of the sandhill crane use area in central Nebraska, and therefore did not affect the cranes. The whooping cranes in Rock, Holt, and Loup counties have been in the same location for several days."
Wally sends us the following confirmed whooping crane sightings, all reported since April 2:
Against the Wind
Cranes and other birds face storms and fierce winds by...well, by facing right into the fierce winds. Have you ever noticed gulls or terns on a windy beach all facing exactly the same direction--into the wind? And when cranes take off in flight during high winds, they always fly into the wind.
Challenge Question #8
How to Respond to Today's Challenge Question
Please respond to only one Challenge Question per e-mail message.
1. Address an e-mail message to: email@example.com
2. In the Subject Line of your message write: Challenge Question #6, #7, OR #8
3. In the body of your message, answer the question.
The Next Whooping Crane Migration Update Will be Posted on April 19, 1999
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