Signs of Spring Everywhere Update: April 26, 1999 Today's Report Includes: Migration in Full Force! The Air Is Full of Food! Challenge Question #19 Birds That Dine on the Wing "Buggy" Ride Challenge Question #20 Fatal Attraction Discussion of Challenge Question #13 Discussion of Challenge Question #14 Discussion of Challenge Questions #15-16 How to Respond to This Week's Challenge Questions Migration in Full Force! Report SIGNS OF SPRING that you see to Journey North! Birds are winging north from the southern states and the tropics. The first migrants ate berries, seeds, water plants and animals, and other end-of-winter items. New migrants are eating insects. As soft, chewable new leaves burst out of tree buds, the first tiny caterpillars hatch out to chew on them. These caterpillars fuel warbler migration. And a rainbow of other migrants are racing in to feed on flying insects. The Air Is Full of Food! Dragonflies and damselflies eat flying insects and in turn are eaten by birds. (from the Digital Dragonfly Museum) Flying insects? How can there possibly be enough to feed the millions of migrants coursing through the skies right now? Entomologists conducting airplane and radar studies find insects higher up than early scientists ever dreamed possible. Birds and bats are up there too. Scientists once thought these larger creatures just migrated at those heights, but now they know they are eating some mile-high dinners. Tiny organisms, from pollen to uni-cellular and multi-cellular animals, fill the skies like plankton fill the ocean. So these microscopic organisms are called "aeroplankton." They form the huge foundation for a food pyramid in the sky. Some tiny insects eat the aeroplankton. Other insects in the sky eat other things--like mosquitoes. Some small creatures in the air are simply migrating--they fly or float on air currents, sometimes moving hundreds or even thousands of miles. Baby spiders ride threads of silk that carry them through the air like balloonists. Some of these little creatures are eaten by dragonflies and other flying predators, and some of the predators are eaten by birds. It's a jungle up there! Challenge Question #19 "What is 'plankton'? How is it similar to aeroplankton? How is it different? (To respond to this Challenge Question, see below) Birds That Dine on the Wing Scientists may not have noticed them up there for a while, but birds have taken advantage of the ecosystem in the sky for thousands of years. Some of the birds that eat flying insects are: American Kestrels Nighthawks Whip-poor-wills Swifts Kingbirds Flycatchers Swallows Buggy Ride! Here's a sign of spring that few people notice: When you go home tonight, look at the windshield and front grille of your car. Can you find any insects? Another fun way to see insects in the night sky is to shine a flashlight straight up and look in the beam. Plan to look once a week and count how many different kinds of insects you can find. Wetlands and areas near lakes and rivers often produce the biggest variety of flying insects. Challenge Question #20 "Why do we usually find more flying insects over wetlands, lakes and rivers than over fields and forests?" (To respond to this Challenge Question, see below) Fatal Attraction The nighthawk on the left, Ginger, was hit by a car. Fred, on the right, crashed into a streetlight wire. Some insects are attracted to light beams, and so nighthawks are drawn to spotlight beams. This can be very dangerous for these fragile birds! They sometimes break their wings on streetlight wires. And when they swoop to grab an insect spotlighted by a car's headlights, they can get killed. To learn more about the problems birds have with lights and how some people are working to help them, visit the Fatal Lights Awareness Program website. Discussion of Challenge Question #13 "To ensure a species' survival, why is it necessary to protect the breeding grounds, the wintering grounds, AND important staging areas? Explain." Birds need all three areas at critical points in their lives. As Ms. Kelly's 7th graders in Fairfax, VA, wrote, "The breeding ground is important because the swans can increase their population. The wintering ground is important because they will have enough food there and they will be safe from the threat of freezing. The staging ground is important because they will be able to rest, have food, and spot familiar landmarks." Discussion of Challenge Question #14 "Name at least one situation when a transmitter can actually save a bird's life." If a bird is in great trouble, the transmitter may show it in the same spot day after day, and the researcher may be able to locate and rescue it. For example, one Snowy Owl researcher in Duluth, MN, put two radio transmitters on owls, and after a few days, lost one signal. He drove all over the city and surrounding area, and finally picked up a very faint signal. He had to find it from two other locations in order to pinpoint the exact location. The owl had dropped down a chimney into an abandoned hotel, and he traced the owner and rescued the very hungry but still healthy owl. He also found two mummified Snowy Owls and several dead pigeons in that room. Without his transmitter, the Snowy Owl would definitely have died. Discussion of Challenge Questions #15 and #16 Calculate Roast and Sir Syd's weights in pounds. How many math books would balance one of them?" Roast weighed 7400 g or 16.3 pounds, and Sir Syd weighed 5150 g or 11.4 pounds. Why are males heavier? Third Graders Cameron, Ardenia, Jesse, and Eliza thought this through very carefully! They wrote, "We think that the male swans are larger than the females because the male needs to protect the family. They both can eat about the same. The female has to use up a lot of calories just to make the eggs. The male can use the calories to grow bigger." How to Respond to Today's Challenge Question Please respond to only one question in each e-mail message. 1. Address an e-mail message to: jn-challenge-spring@learner.org 2. In the Subject Line of your message write: Challenge Question #19 OR #20 3. In the body of your message, answer the question. The Next Signs of Spring Update Will be Posted on May 10, 1999. Copyright 1999 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form