Loon Migration Update: March 23, 2000
Does Early Ice-Out Bring Early Loons?
"Common Loon seen 4 pm March 18th on Monona Bay, a part of west area Lake Monona. This is the earliest I have ever seen one here since keeping records back to 1985." (firstname.lastname@example.org)
Now we're curious! Can loons wintering in the south time their migration to arrive on open lakes? Can they use weather as a timing tip? Will they come earlier than usual because of this? Stay tuned! We expect the migration to take off very soon, and we'll all have a chance to see if loons come early because winter was warm.
Loon #2539, Where Are You?
Challenge Question #7:
Q and A with Kevin Kenow
In 1998 Kevin Kenow of the U.S. Geological Survey and his co-investigators accomplished the first-ever tracking of loons using radio telemetry. With only band recovery data to go on before, this was almost as good as flying with the loons! You'll enjoy this Q and A with Kevin:
Q: What did you want to learn from this project?
A: "This project provided us the opportunity to look very specifically at the timing of migration, use of specific staging areas prior to migration, stop-over areas used during migration, and ultimately wintering grounds of individual birds. The types of questions that came to mind were: What is the relationship between breeding lakes and staging areas? Breeding lakes and wintering grounds? How is the timing of migration influenced by weather patterns? What are the habitat requirements of loons during migration? How broad an area do wintering common loons from the upper midwest use? How long does migration from breeding to wintering areas take?"
Q: What did you learn that surprised you the most?
A: "Documentation of use of inland lakes and reservoirs during migration."
Q: Did you watch weather during the migration period? If so, what did you learn about migration and weather?
A: "Yes. The weather during fall 1998 was fairly mild and temperatures had only occasionally dipped below freezing through the end of October. A high pressure system over southern Canada brought cooler temperatures to Minnesota/Wisconsin around 1 Nov. The system dominated the weather until replaced by a record low pressure system that brought winter weather into northern MN and WI on about 10 Nov. Initial movement of this bird appeared to be associated with these weather events."
Q: Did you have any sensors on the bird indicating temperature (or other variable) that told you whether the loon was flying or at rest when the readings were taken? Did you confirm whether the loon traveled at night or during the day?
A: "The transmitters were of limited life so we had to schedule transmissions to conserve battery power. The transmitters were programmed to signal every 3.3 days prior to the anticipated period of migration (August through mid-September), every 2.3 days during the anticipated migration (approximately mid-September through the first week in December), and every 4.3 days for the remaining life of the transmitter. We were not able to determine whether the bird was in flight or resting during transmission. Due to the infrequent transmissions, we were unable to determine whether travel was during the night or day."
Q: Did this loon return on the nesting lake again last spring?
A: "Yes, it was observed on the same territory again in 1999. It sounds like the pair failed to raise chicks again in 1999."
Now the BIG question on everyone's mind: Will Loon #2539 return again in 2000? We hope to have the answer soon!
Focus on Feathers
Loons feed in cold areas of the ocean, where food is most abundant. They return to northern lakes almost immediately after the ice goes out, when the water temperature is barely over freezing. A loon whose skin came in contact with that frigid water would quickly die of hypothermia. Fortunately, loons can keep their skin dry even when diving as deep as 60 meters down. How? Their feathers!
Who Needs Wet Suits With Feathers Like These?
A loon's body feathers are two main types: contour feathers and down feathers. Down feathers are soft, fluffy gray feathers that insulate a loon's body to hold its heat inside. These are like the stuffing in a human's down jacket, or a nice thick sweater. The best thing about down is the insulation it provides. But you wouldn't want to face a rainstorm in just a sweater! Like a warm sweater, the worst thing about down is how absorbent it is. Down quickly gets soaked and mats together when wet. So not only do loons have to keep their skin dry, but also keep all of their down feathers dry. They do this thanks to their outer, contour feathers. These feathers cover every millimeter of down and skin, working like a perfect rain suit, or a diver's dry suit.
Contour feathers take their name from the fact that they give loon bodies their shape, or contour. Loon contour feathers are beautifully patterned black and white. The white parts or neck feathers are longer than the black, giving a loon's neck the texture of an exquisite velvet corduroy.
Although the loon's skin is protected by down and contour feathers, its beak, eyes, legs, and feet are bare. That makes us wonder:
Tracking a Loon: Responses to Challenge Questions #4 and #5
Challenge Question #4 asked, "Where does Loon #2539, which nested in Minnesota, go for the winter?"
Using the latitude and longitude in the loon data as clues, the answer is the Gulf Coast near Pensacola, Florida.
Battery Power: Challenge Question #5 asked, "Why do you think the transmissions followed the time schedule you see in the data table?"
If you didn't know the answer already, you found it in Kevin's interview above! (Transmissions had to be scheduled in order to conserve battery power.)
Answers Lead to More Questions
After thinking about the answer to CQ #4 above, we have another new question for you:
Challenge Question #12:
How to Respond to Today's Challenge Questions:
Please answer ONLY ONE question in each 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, #8, #9, #10, #11, OR #12).
3. In the body of your message, give your answer to ONE question.
The Next Loon Migration Update Will be Posted on April 6, 2000.
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