Common Loon Migration Update: March 25, 1999 Today's Report Includes: Loons Starting to Migrate! Loon Migration Data Challenge Question # 4 Reappearing Like Magic! Challenge Question # 5 Discussion of Challenge Question # 2 Discussion of Challenge Question # 3 How to Respond to This Week's Challenge Question Loons Starting to Migrate! Common Loon Winter and Breeding Range Map by Macalester College Loons are on the move! This week a few left the ocean for inland lakes. To see where they have been reported so far, check our Loon Migration Data. To use the data, try our Analyzing Loon Data Activity Most lakes in southern states stay open all winter. It might seem as though some loons would winter on them, but they virtually never do. Lakes that freeze every year often have fewer plants and fish than those that have enough warmth and sun for a year-long growing season. Warm lakes are great for wintering herons and egrets, but not for loons. Why not? Challenge Question # 4 "Name some possible reasons why loons don't winter on inland lakes." To respond to this week's challenge question, see below Reappearing Like Magic! Report the first Loon you see this spring to Journey North! People living near small lakes in Canada and northern states often marvel that loons seem to appear the first day that the ice is out. The date of northern ice-outs vary greatly from year to year, so people watching for loons often wonder whether the loons know by instinct that the ice will go out on "their" lake on a particular date. What do you think? Challenge Question # 5 "How do so many loons manage to time their arrival on their breeding lake for the very day that the ice goes out?" (To respond to this week's challenge question, see below.) Discussion of Challenge Question # 2 Loon in breeding plumage Photo: Woody Haage We asked, "Why do loons lose and then grow all their flight feathers at once, instead of one or two at a time the way crows, hawks, and eagles do?" The seventh graders at Iselin Middle School explained this well and very concisely: "Loons grow and lose all their feathers at once because if they grew one or two feathers at a time the loons cannot fly. They are completely flightless without every single one of their feathers." Loons have relatively heavy bodies and small wings--both adaptations for diving deep into water. With a complete set of flight feathers, their wings have just about the minimum amount of surface area to hold up their bodies. Missing even one or two feathers, their wings may not support their bodies, so to minimize the time that they are flightless, they molt all the feathers at once. Discussion of Challenge Question # 3 "Which one of the loon vocalizations (hoot, wail, tremelo, yodel) do you think can be heard on the wintering grounds? Explain your reasons." Several students used excellent reasoning to tackle this question. First and second graders Julie, John, Krista, and Stephen figured it this way: "We think that the you can hear the hoot on the wintering grounds. We know it isn't the tremelo because that is a warning sound you hear when people approach the nest. The yodel is to attract a mate so that would be a spring sound. We have heard the wail in the summer here in Vermont. So it has to be the hoot." Dr. Judith McIntyre wrote in her book, The Common Loon: Spirit of Northern Lakes, "Hoots are about the only call used during the winter, but tremolos and yodels can be heard infrequently. Loons apparently are competent to perform all calls in their repertoire at any time of the year, but are not in physiological condition to do so." Changes in hormones are important influences on loon calls just as they're important influences on other territorial and breeding behaviors. All Recordings Courtesy of Lang Elliott Nature Sound Studio Listen to the Loon's Hoot Wait for download; 110 K file. Listen to the Loon's Wail Wait for download; 202 K file. Listen to the Loon's Tremolo Wait for download; 115 K file. Listen to the Loon's Yodel Wait for download; 112 K file. How to Respond to Today's Challenge Question Please respond to only on Challenge Question in each e-mail response. 1. Address an e-mail message to: jn-challenge-loon@learner.org 2. In the Subject Line of your message write: Challenge Question # 4 OR # 5 3. In the body of your message, answer the question. The Next Loon Migration Update Will be Posted on April 8, 1999 Copyright 1999 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form