Hummingbird Migration Update: April 15, 1999
Today's Report Includes:
Hummers Whizzing North!
We've had about 150 reports of Ruby-throated Hummingbirds this week, reaching as far north as New York, Pennsylvania, and Ohio, almost to the shores of the Great Lakes. What a lot of data!
Beware! Spring Weather Ahead
Spring is here, but that doesn't mean there won't be any more cold weather! Snow is predicted this weekend in the northern Great Lakes area. How can exhausted migrants deal with bad weather?
It takes a lot of energy to keep hummingbird bodies going. Ruby-throated Hummingbird hearts beat over a thousand times per minute when active and their wings beat 60 times per second. Their body temperature is about 108 degrees. Imagine trying to keep a jelly bean at 108 degrees F in a freezer!
Hummers can survive cold temperatures for at least a while--as long as they have food. Fortunately, their method of migration ensures that they will have at least some food wherever they are once they clear the Gulf of Mexico. Over land they stop to eat a lot as they migrate..
What happens if the weather gets too cold? During northern nights, they let their body temperature fall to close to air temperature to conserve energy. This is called "torpor," and works the same as when we lower the thermostat in our houses at night to save energy.
Hummingbirds aren't in real danger when the temperature is in the mid 30's, as long as they ate enough food the day before. But when it freezes, they shiver on and off all night to prevent their blood from freezing. This takes so much energy that they just barely survive the night. They start shivering hard as they come out of sleep, and need a big breakfast right away.
Food! Glorious Food!
During this critical time of year, hummingbirds are always on the thin edge between death and survival. Your hummingbird feeder may even mean the difference between life and death for one! Hummingbirds give us a lot of beauty and entertainment. It's nice for us to sometimes return the favor.
But hummingbirds obviously survived long before people were setting out sugar water for them. If you were a hummingbird, what could you find to eat today? Keep a lookout for early spring flowers with nectar. And even before flowers such as apple and cherry blossoms open, there is another source of food available for hummers. They can sip sap, too!
But this raises a question:
A Sappy Challenge Question #11
"How do you suppose a hummingbird can get sap from a tree?"
(To respond to this challenge question, see below.)
Discussion of Hummingbird Math Challenge Questions
Students at Ferrisburgh Central School have been busy.
#4 How many paper clips would it take to balance a hummingbird? Sixth grader Andrea L learned a tip that made the math easy: "It would take about 2 and three fourths paper clips to balance out a hummingbird. I found this out by knowing that a paper clip weighs about 1 gram. This problem was simple once we found out that a paper clip weighs one gram."
#5 A hummer's heart weighs 2.4% of its total body weight. How much would its heart weigh?
Third Graders Robert S., Britany S, Hilary D., Erin P. and Justin B. came up with the same answer as fifth graders Chris and Hannah who explain, "The ruby throated hummingbird's heart would weigh 0.0648 grams. First, we divided 2.7 grams( his weight) by 100 to get 1%. Then we multiplied that by 2.4 and got the weight of his heart."
#6: "Using our discussion of Challenge Question # 3, how many times would a hummingbird's heart beat during
the flight between Campeche, Yucatan, and Galveston, Texas?" Oops! This was pretty much a repeat of Challenge
Question #3: We figured it beat about 6.5 million times on that flight.
How to Respond to Today's Challenge Questions
Please send only ONE answer in each e-mail message
The Next Hummingbird Migration Update Will be Posted on April 29, 1999.
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