Common Loon Migration Update: March 11, 1999 Today's Report Includes: Getting Ready Challenge Question # 2 Red-throated Loons On the Move Looney Tunes Challenge Question # 3 Discussion of Challenge Question # 1 How to Respond to This Week's Challenge Question Getting Ready! Common Loon Winter and Breeding Range Map by Macalester College Common Loons on the oceans are preparing for their migration right now. Most are starting to molt into their black-and-white breeding plumage, but few can fly yet. Loons drop all their flight feathers in February, and it takes a while for the new ones to grow in. Until the feathers are fully grown, loons are completely flightless. We often see crows, hawks, and eagles flying without one, two, or even three flight feathers. We virtually never see flying loons missing even one feather. Challenge Question # 2 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? (To respond to this week's challenge question, see below.) Red-throated Loons On the Move Report the first Loon you see this spring to Journey North! Common Loons may not be quite ready for their Journey North, but their relative, the Red-throated Loon, is already on the go. (Red-throated Loons winter in much the same range as Common Loons, but most breed farther north than Commons.) One was seen in Wisconsin last week, and many are moving along the coasts. Loon Biologist Lucy Vlietstra sent us this letter from Monterey Bay, California: Dear Journey North: Last week was the first big pulse of migrating loons in Monterey Bay. Red-throated Loons were showing up on shoreline surveys in the hundreds where they normally number in the mere tens. Large groups of Red-throated Loons were also observed flying north throughout the day. This week, numbers of Red-throated Loons are still high, indicating continued migration north. Pacific Loon photo: H.R.Spendelow Jr Patuxent Bird Identification InfoCenter. Red-throated loons are usually the first of the three most abundant loon species in Monterey Bay (Red-throated, Pacific, and Common) to begin spring migration. Pacific Loons are increasing in number, suggesting these birds are also beginning to move north. Many Pacific Loons that migrate through Monterey Bay stop over in large drifting groups. Groups thus far have been small; but it is still early in the season to expect many migrating Pacific Loons. Common Loons are just now beginning to replace winter plumage with summer plumage. Here and there, I see Common Loons with spotted backs and blotchy black and white faces, but the rest of their plumage is still that of the drab winter pattern. Although I observed a couple Common Loons in nearly full black-and-white breeding plumage, I still haven't seen any Common Loons in flight. It seems that they may need a little more time before most Common Loons in Monterey Bay reacquire their full set of flight feathers needed for spring migration. --Lucy Vlietstra, Monterey Bay, California Looney Tunes To learn what these vocalizations mean, see Journey North's Loon ID Page 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. 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." (To respond to this week's challenge question, see below.) Discussion of Challenge Question # 1 Loon Salt Glands The skull on the left shows the depression where the salt glands were removed photo: Judith McIntyre in The Common Loon, Spirit of Northern Lakes We asked how you think loons adapt to salt water. A couple of students guessed that loons adjust to salt over time. The problem is, they don't have time to adjust! They are often hungry after a long flight when they first reach the ocean. Suddenly they only things they can eat and drink are salty fish and salty water. Their bodies must be able to handle salt right off the bat! So loons have a special adaptation--salt glands that fit in their skull between their eyes. Dr. Judith McIntyre, an authority on the Common Loon, found that "even young chicks, no more than two weeks old, are competent to remove salt if they are fed saline (salty) solutions." 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 # 2 OR # 3 3. In the body of your message, answer the question. The Next Loon Migration Update Will be Posted on March 25, 1999 Copyright 1999 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form