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Hummingbird Migration Update: March 14, 2002
Today's Report Includes:
- Latest Migration News
- Rubythroats Waiting in the Wings
- Rufous Hummers Ignoring Snow
- Don't Walk; Challenge Question #4
- Wrong Turn?
- Needle in a Haystack: Discussion of Challenge Question #2
- Torpor: Discussion of Challenge Question #3
Latest Migration News: Ruby-throated Hummingbirds
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Ruby-throated Hummingbird Courtesy of Lanny Chambers, Hummingbirds.net |
Rufous Hummingbirds
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Rufous Hummingbird Courtesy of Mike Patterson |
Rubythroats Waiting in the Wings
Record low temperatures were recorded across south and southeast Texas on March 4. Coastal areas like Rockport and Palacios had temperatures in the low 20s. Many flowering plants died. Do you think this cold snap will slow Ruby-throated Hummingbird migration?
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Departure from Normal |
Minimum Temperatures |
Journey North Science Writer Laura Erickson doesn't think so. She says to think carefully about rubythroat migration.
Some of them do winter near the southeastern coastline, but the vast majority winter in the tropics. They have
not arrived in the U.S. yet. They have no way of knowing what the weather is like in Texas (unless they have VERY
tiny weather radios!) They time their migration using daylength, so most don't move north until April, when the
worst winter weather is usually over.
Rufous Hummers Ignoring Snow!
Both male and female Rufous Hummingbirds are on the move along the coasts, despite snow and cold.
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"There were more Rufous Hummingbirds reported from southwestern British Columbia this week. Willamette Valley reports show an increased inland presence as well. There were also three arrival reports from southeastern Arizona." Mike also pointed out that birds migrating along the coast are averaging about 5 days ahead of schedule."
Mike adds that the first female Rufous Hummingbirds arrived in Waldport and Coos Bay, pretty much on time. Observers were seeing several males at feeders and even some territorial displays.
March 11, 2002
"We had snow in the region at elevations down to sea level last week which is a rare event even in December
and January for lowlands in the Pacific Northwest and especially surprising in March." The weather did not
appear to slow the Rufous migration, however. Mike said that some are even going up the mountains--the highest
elevation they've been spotted at so far is 2400 ft., at Oakridge, in the foothills of the Cascade Range.
Rufous females have now been reported as far north as Sooke, BC. and a female carrying nest material was reported
on March 10 in Waldport, OR. Along the Oregon coast males are performing their breeding displays. Looks like both
and females may be starting to settle in. So many rufous are on the go while rubythroat migration hasn't even kicked
in. What's the difference? See our discussion
of Challenge Question #1 .
To learn more about Mike Patterson's research on Rufous Hummingbirds, see his website, Hummingbirds
and Flowers
Don't Walk
Why do geese fly south for the winter? Because it's too far to walk!
That silly joke is grounded in truth--the reason so many birds are migratory compared to other animals is because birds travel so easily. Of course whales, manatees, and caribou migrate, but most migratory animals fly from place to place, whether they're butterflies, bats, or birds.
But the joke wouldn't have worked if we asked why do hummingbirds fly south for the winter, because even if it was very close, hummingbirds just can't walk. Flying is the only way they can get anywhere! These tiny birds have so many unique adaptations for flying that their bodies have lost some other abilities. Hummingbirds even belong to an order of birds called Apodiformes (ay-pod-ih-FOR-meez), which means "without feet"! They really do have feet, but they're so tiny, and their legs so short, that the only thing hummers can do with their feet is to cling to tiny twigs and other very thin perches.
To learn more about some adaptations that make hummingbirds exceptional flyers, check out our lesson:
Think about the chest muscles that operate a hummingbird's wings. Then come back to answer this:
Challenge Question #4:
"Muscles only have power when they're twitching, getting shorter. If all of a hummingbird's flight muscles are in its chest, how might those muscles be designed so it can have power when it raises AND lowers its wings?"
(To respond to this question, please follow the instructions below.)
Wrong Turn?
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Brrrr! The team arrived on March 7 at 7 a.m. and waited in the 30 degree cold for almost an hour before the
hummer appeared. Bill trapped it and discovered that some of the gorget (throat. pronounced GOR-jit) spots
were velvety black and some were brilliant purple; it could be none other than a second-year male Black-chinned
Hummingbird, a species that normally breeds in the West and winters in Mexico! Bill writes, "We were especially
pleased to be eye-to-eye with a Black-chinned Hummingbird because it was the first we had ever captured; plus,
it became the fourth vagrant hummingbird species banded by Center staff in South Carolina during the winter of
2001-2002." (To learn about Hilton Pond Center's vagrant hummingbird project, see Vagrant
Hummers.)
Needle in a Haystack! Discussion of Challenge Question #2
Last time we mentioned that Bill Hilton Jr. has banded over 2500 Ruby-throated Hummingbirds. Other banders have banded thousands more; yet, not one of these banded ruby-throats has ever been found on its wintering grounds, even though we know where they winter. We asked, "Why do hummingbird banders who band thousands of birds re-find so very few?" Kayla, Lyndsay, Diane, and Cody in Mrs. Voelker's Fifth Grade class in Andover, Ohio, and Dylan and Kate in Grade Six
at Ferrisburgh Central School in Vermont helped with these ideas:
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Also, many of the banded birds that people find are discovered after they're dead. The most commonly found banded birds are ducks and geese--when a hunter shoots a bird and holds it, it's easy to notice its band! Many other banded birds are reported when they are killed at windows or on roads and picked up by someone. The problem with hummers is they're so tiny. When one hits a window, people inside hardly ever hear the bonk. And a bird that weighs less than a nickel can disappear into fairly short grass.
Second graders Hannah, Garrett, Jack, and Dustin at Ferrisburgh Central School also pointed out that "The birds do not have a radio transmitter on them, so scientists can't track them as easily. They are very fast, so they would be hard to catch. They are very small, they wouldn't be easy to see. If they die, another animal might just eat it and nothing would be left of that bird."
Torpor: Discussion of Challenge Question #3
Last time we said that hummingbirds are some of the strongest flyers in the world, and that both Rufous and Ruby-throated Hummingbirds are good at migrating. But both species go into torpor at night, even in the middle of summer! Even hummingbirds living in the Central and South American tropics go into torpor. We asked you to "List as many advantages and disadvantages to torpor as you can think of. What are some reasons why hummingbirds would go into torpor rather than just flying where it's warmer at night?" Sixth graders Dylan and Kate from Ferrisburgh Central School in Vermont came up with some great answers, included below.
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an e-mail message to: jn-challenge-humm@learner.org
2. In the Subject Line of your message write: Challenge Question #4
3. In the body of your message, answer the question.
The Next Hummingbird Migration Update Will Be Posted on March 28, 2002
Copyright 2002 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to our feedback form
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