Happy Earth Day! Migratory species remind us that we live in an interdependent world. Many environmental problems cross national boundaries, just as these species do, and international cooperation is required to resolve them. As you celebrate Earth Day today, keep this example in mind: Canada plays a central role in protecting the U.S. national symbol. Almost half of all eagles that winter in the lower 48 States nest in Canada.
New migration data for our 3 eagles has been added to the charts below. Compare the data for each eagle and see if you can answer today's Challenge Questions:
Challenge Question # 93
"Where was each eagle on Earth Day in 1992, 1994 and 1995?
(Earth Day is April 22nd.)
Just in case you didn't answer last week's Challenge Question, here it is again:
Challenge Question # 82
"When did each of our 3 eagles begin its migration? If the dates are different, what do you think this could mean?"
To respond to these Challenge Questions please follow the instructions at the end of this report.
A Good Day for Flying?
From an eagle's point of view, what makes a good day for migration? We asked Peter Nye (our science guy) how weather affects eagle migration. Here's what he had to say:
"The eagles we have followed are typically in no hurry to "get- going" each morning during migration; getting on their way often in late morning or mid-day. Perhaps they are scoping out the days whether fully to understand what kind of migration day it will be for them.
"Eagles move great distances by catching thermals and soaring to great heights. Thermals are areas of uplifting air created from sunshine or topography, such as winds hitting a mountain side. Eagles have been observed soaring and moving at altitudes of up to 2 miles, or over 10,000 feet. I think typically these soaring and long-distance glide-flights occur between 3000-7000 feet up. 'Average' flight speed during migration is around 30-40 miles per hour, although I am sure they hit greater speeds on occasion. By soaring, eagles can travel great distances with little effort. In contrast, birds that migrate by "powered flight" must flap their wings continuously.
"Like many other raptors (as well as smaller passerines too), bald eagles look for days with generally southerly winds to migrate. As you have undoubtedly read with other bird migration, these favorable southerly winds are created either as a low pressure system is approaching (with its counterclockwise wind rotation), or as a high pressure system passes by (clockwise winds).
"Bald eagles migrate only during the day (as opposed to many other species of birds), and typically move between 75-150 miles per day (although they are certainly capable of longer one-day movements). We have witnessed that if a good meal is available, or if poor whether sets in, a northward-moving eagle may stop for a day or more along its journey. Rain, snow or low clouds can stop migration. Eagles are very visually oriented during migration, likely relying on considerable height to recognize major feature such as waterways to guide them where they are going. When these eagles leave New York, mostly during the last two weeks of March, the whether can be quite unsettled and areas in Canada to the north are largely still very frozen and snowy. This may necessitate stopovers at a food source of up to several days."
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Migration Data Charts
(Data that is new this week is marked with an * asterisk.)
1992 Eagle
Date Latitude/Longitude
Feb. 29 41.315 N, 74.716 W
March 02 41.522 N, 74.541 W
March 05 41.496 N, 75.032 W
March 09 41.558 N, 74.777 W
March 10 41.530 N, 74.719 W
March 12 41.581 N. 74.576 W
March 15 41.565 N, 74.741 W
March 16 41.639 N, 74.663 W
March 19 41.591 N, 74.495 W
March 21 41.495 N, 74.799 W
March 22 41.537 N, 74.447 W
March 26 42.094 N, 74.800 W
March 29 42.091 N, 74.870 W
March 31 41.652 N, 74.715 W
April 1 42.139 N, 74.780 W
April 5 41.626 N, 74.717 W
April 9 41.389 N, 74.645 W
April 11 42.458 N, 74.482 W
April 15 44.774 N, 74.063 W
April 17 46.027 N, 75.545 W*
April 19 48.889 N, 71.308 W*
April 21 48.807 N, 71.808 W*
1994 Eagle
Date Latitude/Longitude
Feb. 28 44.333 N, 75.983 W
March 1 44.300 N, 76.001 W
March 3 44.350 N, 75.967 W
March 7 45.183 N, 76.450 W
March 10 45.150 N, 76.466 W
March 11 45.216 N, 76.433 W
March 13 45.350 N, 76.466 W
March 15 45.516 N, 76.450 W
March 17 46.250 N, 75.883 W
March 19 46.350 N, 75.766 W
March 22 46.266 N, 75.966 W
March 23 46.300 N, 76.000 W
March 25 46.300 N, 75.900 W
March 27 46.350 N, 75.866 W
March 29 46.516 N, 76.033 W
March 31 48.450 N, 74.966 W
April 2 48.383 N, 74.933 W
April 5 48.400 N, 75.133 W
April 6 48.366 N, 75.033 W
April 8 48.316 N, 75.000 W
April 10 48.316 N, 75.200 W
April 14 48.316 N, 75.200 W*
April 19 48.316 N, 75.200 W*
April 22 48.316 N, 75.200 W*
1995 Eagle
Date Latitude Longitude
March 1 41.234 N 75.186 W
March 17 41.558 N 75.122 W
March 20 42.041 N 74.925 W
March 27 43.731 N 73.072 W
March 31 44.969 N 72 268 W
April 2 46.033 N 71.532 W
April 6 46.758 N 70.294 W
April 8 48.258 N 70.028 W
April 10 48.981 N 68.798 W
April 14 49.280 N 68.386 W
April 16 50.018 N 68.143 W*
April 22 52.230 N 67.372 W*
How to Respond to Challenge Question # 93 (or #82)
1. Address an e-mail message to: jn-challenge@learner.org
2. In the Subject Line write: Challenge Question # 93 (or #82).
3. In the body of the message, answer ONE of these questions:
(Please answer ONLY ONE question per e-mail message!)
Challenge Question # 93
"Where was each eagle on Earth Day in 1992, 1994 and 1995?
(Earth Day is April 22nd.)
or
Challenge Question # 82
"When did each of our 3 eagles begin its migration? If the dates are different, what do you think this could mean?"
The Next Bald Eagle Migration Update Will be Posted on April 29, 1996.
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