No oriole sightings have been reported from the Gulf States yet. Do you think we'll have a sighting by next week's report? From which state do you think the first report will arrive? According to Noel Wamer of Tallahassee, Florida, most of the orioles that spent the winter at his feeders left last week. Where do you suppose they will breed?
Ruby-throated hummingbirds, the tiny neotropical migrants that everybody loves, have now been reported in Texas, Louisiana and Arkansas. When do hummingbirds return to your region? What do hummingbirds eat and how might this affect the timing of their migration?
Thanks to ornithologist David Aborn of the University of Southern Mississippi, you'll find your first Weather Forecast for the Birds below. By coincidence, today's whooping crane report discusses the same weather patterns and how they affected whooping crane migration last week. After reading David Aborn's weather lesson and trying out the activities below, see if you can answer this Challenge Question:
Challenge Question # 80
"If a high pressure system were directly to the west of your town and a low pressure system were directly to the east, from which direction would the wind be blowing? Do you think this would be a good time for songbirds to migrate? How about whooping cranes? (Note: Assume you are in the Northern Hemisphere.)
To respond to this Challenge Question, please follow the directions at the end of this report.
To: Journey North
From: David Aborn,
University of Southern Mississippi
"Dear Students:
"As I am sure you are all aware, bird migration is very dependent on the weather. Over the next several weeks, I will be helping you to understand weather maps and what they mean for bird migration.
"As those of you living in the Northeast know, a cold front passed through the country last weekend. On a weather map, such as those found at the National Weather Service's web site or the USA Today's web site, cold fronts are represented by a blue line. Behind, the front, you will see a letter "H", which stands for a high pressure system. The winds on the front or eastern half of the high pressure center are coming from the north, which means migrating birds will encounter headwinds.
"Birds want to fly with tailwinds and avoid headwinds. This means that for a few days after a cold front passes through in the spring, birds will be forced to land because it is too difficult for them to fly. This is when bird watchers and researchers see lots of birds. This is especially true along the Gulf coast because the birds have made a 500 mile non-stop flight and are already low on energy. If you check with the people monitoring migration along the Gulf, this weekend was probably good for seeing birds.
"As the high pressure center moves east, the winds start coming from the south, which is good for flying. If you are a researcher or a birdwatcher, these days can be very slow. Take it from me, I have been there. The birds are able fly much farther with the tailwinds and therefore do not land. Migration continues like this until the next cold front passes through. If you look at a weather map you will see there is another cold front in the western United States. It is supposed to move across the Gulf coast states this weekend, so tell your migration monitors to prepare for some big days.
"If you have any questions about weather and migration, or migration in general, I would be more than happy to answer them. Otherwise, I will check in next week and tell you what happened after this latest moves through, and to talk about what may happen next. Have fun!"
David A. Aborn
University of Southern Mississippi
david_aborn@bull.cc.usm.edu
Try This:
* On a piece of paper, draw an "H" to represent a high pressure system and an "L" to represent a low pressure system. Next, draw arrows in a CLOCKWISE direction around the H and in a COUNTER- CLOCKWISE direction around the L. These arrows represent the wind direction associated with these pressure systems. Now re-read the information David Aborn provided above. Does this help you answer today's Challenge Question?
* Go outside and stand with you back to the wind. As a general rule, a high pressure system should be to the right and a low pressure system to your left. Look at today's weather map and see if this is correct.
* What is today's barometric pressure? Find out, either by reading your own barometer or by finding this information on Internet. Is the barometric pressure rising or falling? Track a high or low pressure system as it approaches your town. Watch how the barometric pressure changes and note the changes in wind direction.
The Following Migration Sightings Collected by the Volunteers of the National Birding Hotline Cooperative and Journey North:
From GEORGIA:
April 2, 1996
Lowndes Co., Georgia
As of Apr. 2, the BALTIMORE ORIOLE was still visiting the feeder in
Valdosta.
From ARKANSAS:
April 5, 1996
RUBY-THROATED HUMMINGBIRDS are starting to return to Arkansas.
People are reminded that the correct mixture for hummingbird nectar
is four parts water boiled with one part sugar.
From FLORIDA:
April 8, 1996
Most of the orioles that came to my bird feeders during the winter
are gone. The adult males all had left by about April 1st. I only
saw three immature males yesterday p.m., on April 7th. Noel Wamer
Tallahassee, FL, USA nwamer@freenet.tlh.fl.us
How to Respond to Challenge Question # 80
1. Address an e-mail message to: jn-challenge@learner.org
2. In the Subject Line of your message write: Challenge Question #80.
3. In the Body of your message, answer this question:
"If a high pressure system were directly to the west of your town and a low pressure system were directly to the east, from which direction would the wind be blowing? Do you think this would be a good time for songbirds to migrate? How about whooping cranes? (Note: Assume you are in the Northern Hemisphere.)
The Next Northern Oriole Migration Update Will be Posted on April 18, 1996.
 |
|
|---|
