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Hummingbird Migration Update: February 26, 2004
Today's Report Includes:
Rufous Hummingbirds
Heading Up the Coast
A week ago, any Rufous sightings were likely in the "over-winter birds moving around" category, says
Mike Patterson. Now that's starting to change! Today's map has a few more data points as Mike reports a pulse of
Rufous Hummingbirds through southern California and one report from coastal Oregon. Mike says, "If the nice
weather continues, reports should start picking up." Migration is underway!
Mike's research project tracks the movement of hummingbirds
and the availability of flowers that provide nectar. (Nectar from flowers provides essential food for hummingbirds.)
In flower news this week, the very first frost-bitten Salmonberry blooms were seen at monitoring sites. Willow
is well along in blooming, and so is the manzanita along the south coast of Oregon. If you live in the West and
see hummers, make sure you report them to Mike. Let Mike know if any flowers are blooming, too!
First Ruby-throat Report!
Both last year AND this year, the first Ruby-throated Hummingbird reported to Lanny Chambers was sighted on February
25. They're coming! What kind of weather greeted the season's first Ruby-throat arrival in Shalimar, FL? Get set
for more Ruby-throat news in our next report. But until then, think about that early Florida arrival as well as
the Rufous hummers up in chilly Oregon. If nights are still cold, how do they survive?
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Hummingbird
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Hummingbird Survival:
Challenge Question #3
Imagine being the tiniest of all warm-blooded animals. Your entire body
weighs less than two dimes. Some insects and worms weigh more than you!
When the air is cool, you must shiver or fly about to keep your body
temperature up, and shivering or flying requires a LOT of energy. From
the time you awake in the morning until you sleep at night, you are
almost constantly doing one of three things: eating high-energy food,
quietly perching while you digest your food, or searching for new sources
of food. Imagine the challenges hummingbirds face every day in order
to stay alive, and especially those early arrivals who come when temps
are still cold. Read about a terrific survival adaptation here:
You'll also find tips that will help you with this
week's challenge question, so send us your answers to...
Challenge Question #3:
"If you burned energy at the same rate as a hummingbird, how much of your favorite food (by weight) would
you need to eat per day? Assuming you are awake 16 hours each day, how much food would you need to eat per hour?"
(To respond to this question,
please follow the instructions below.)
You're the Scientist:
Link to Lesson
How is this spring's Rufous hummingbird migration different from last year's? Here's the Rufous migration map for
this same week LAST year, and this important fact: In the West, winter 2003 was milder, with temperatures averaging
4-5 degrees F. higher than the previous two years for January. Last year people kept telling Mike Patterson that
the hummingbirds were early. Mike wondered: How early? Using data collected over the last three seasons, he compared
the previous earliest records to those received in 2003. Think like a scientist as you work with Mike's data to
make some discoveries. Find Mike's data and questions here:
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Why can Rufous hummingbirds
start migrating so much earlier than Ruby-throats?
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Timing is Everything:
Discussion of Challenge Question #1
"Compare the range maps. Which hummer species has to cross a large body of water on its journey north? How
would this help explain why Rufous hummingbirds start migrating so much earlier than Ruby-throats?"
Aidan, along with Kari and Jessie in Mrs. Erdmann's
5th grade TAG class at South O'Brien Middle School were among students who correctly answered that Ruby- throated
hummers have to fly over the Gulf of Mexico. Mallika, a 4th grader at Harrington School in Lexington MA, pointed
out that Rufous hummers fly over a land mass, while Ruby-throats have to fly over a stretch of water without stopping.
This has more to do with the reason why Rufous hummingbirds migrate so much earlier than Ruby-throats. The map
reminds us that Rufous is a western species, and starts its migration from Mexico up the West Coast. Because it
doesn't have to cross a large body of water, a rufous can fly small distances at a time. Unlike Ruby-throats, many
of which cross the Gulf of Mexico to get to the eastern states, Rufous hummmingbirds can leave as early as weather
conditions permit. The ocean keeps temperatures more moderate along the Rufous's Pacific coast migration route
than in inland areas, and early Rufous hummers aren't as likely to face dangerous low temperatures as Ruby-throated
hummingbirds would in the East. Also, flowers and insects to feed the hummingbirds are available earlier on the
milder West Coast.
Why Come Back? Discussion
of CQ #2
"If things are so good "down south," why don't hummers stay there all year?"
Jeremy and Anthony R. from Iselin Middle School/grade
7 pointed out that the warm tropics are good for wintering and building energy but the birds return north for lots
of flowers and good nesting places for breeding. Chris, Sriram, Ariel, Stephanie V. and Kevin thought about the
amount of food necessary to feed the whole population. Jessie from South O'Brien Middle School talked about the
temperatures. And one person put crowding and space and food supply all together in this answer: "Hummingbirds
migrate back north because of land mass and geography. There is more land mass and places for nesting and spreading
out in North America, in the U.S. and Canada, than in Central America or Mexico. More land also gives them more
possible breeding sites."
Hooray! In spring an enormous breeding range opens up after being freezing cold and covered with snow all winter.
This offers hummers and other birds PLENTY of space and food for themselves and their young, without much competition,
all through the summer. When the weather turns cold and their food sources diminish, the tropics will be a welcome
refuge again.
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 #3.
3. In the body of EACH message, give your answer to the question above.
The Next Hummingbird Migration Update Will
Be Posted on March 4* , 2004.
(*Data Only)
Copyright 2004 Journey North.
All Rights Reserved.
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