Signs of Spring Update: February 7, 2003
A New Challenge: West Nile Virus
Most mosquito bites make people itchy, but don’t cause any other problems, at least in the United States and Canada. (Mosquito-borne diseases are a serious problem in tropical areas of the world.) But in 1999, a disease appeared in New York that had never before been seen in America, West Nile Virus. And ever since then, this disease has been spreading, killing birds, horses, some other animals, and humans. Birds have thick feathers to protect them, yet they get many bites. How can mosquitoes possibly bite them? Think about it, and then answer
How did the virus get here? How does it work? How are we fighting it? To learn more about West Nile Virus and what people are doing to protect humans and animals from it, see Current Happenings: Lots of Good News! In Pensacola, Florida, someone is getting garden beds ready for spring planting. Daffodils are poking through the ground in Oolitic, Indiana, and they already have buds in Vale, North Carolina. Cardinals are singing in Lewistown, Missouri, and bluebirds have been spotted in Vincennes, Indiana. These field notes all came from you and other Journey North participants. Remember to share your sightings of first frogs, earthworms, red-winged blackbirds, barn swallows, emerging leaves, flowing sap, melting ice and other spring events. You can report any of these things, plus read all the field notes of other participants, by pressing the "Owl Button" at the top of every Journey North page.
And here's an exciting discovery: a Gray Jay banded last August was just confirmed as being the oldest Gray Jay ever recorded! How old was the bird? Meet the Gray Jay and find out more about how scientists learn how old wild birds can live to be here: Frozen Fruits: Discussion of Challenge Question #2 Last time we asked, "Why do you think robins might prefer eating small berries to big chunks of other fruits? Give at least two reasons." Frozen fruits are much harder than warmer ones. Kasey from Ms Deede's class notes that "robins might prefer the small berries than the larger chunks of fruits because they are smaller and softer and easier to swallow whole. This is important because they could choke if the berries are too large. Robins swallow the berries whole because they have no teeth to chew with." Also, frozen fruit will chill a bird until it thaws in the bird's stomach. Frozen berries are easier to thaw out than big chunks of frozen apple. Frozen Insects: Discussion of Challenge Question #3 Last time we asked, "If insects can produce enough antifreeze in their tissues to stay alive and even active when the temperature is below freezing, why is it still hard for them to lead normal lives?" Antifreeze may keep the tissues from freezing, but in frozen conditions, insect body temperatures are still very cold, making the insects very sluggish. And virtually all insect food is gone or difficult to get at in winter: there are no leaves on trees, and the dried, brown leaves on the ground have little nutritional value. Frozen plant tissues are too hard for insect mouth parts to chew. Some kinds of insects are active on warmish days, but overall, most insects just bide their time waiting for more pleasant days to come. Please Report "Signs of Spring" From Your Part of the World!
How to Respond to Today's Challenge Questions:
1. Address an e-mail message to: jn-challenge-spring@learner.org
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