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Common Loon

Journey North News will be posted onThursdays

Feb. 26, Mar.12, 26, Apr. 9, 23 May 7

Common Loon Migration Update: March 12, 1998

Today's Update Includes:

Photo: Dr. F.G. Irwin

News From The Loon Wintering Grounds

Here's the latest news from our loon Biologists in California and Florida that suggests the loons are in the early stages of attaining their breeding plumage, readying themselves for migration!

After reading their Field Reports, see if you are "ready" to answer the Challenge Question that follows their reports.

Field Report From Loon Wintering Grounds in California

To: Journey North
From: Lucy S.Vliestra

March 10, 1998
"Common Loons are still not showing many signs of migration. Most are still in full winter plumage, although some are starting to show hints of breeding plumage including black faces and white-spotted backs. Red-throated loons and Pacific loons are really changing plumage now and nearly half of all red-throated loons that I see are in full breeding attire. I am also seeing larger and larger groups of Pacific loons lately, potentially pre-migratory aggregations that have been described by local birding authorities."

"Gray whale movements through Monterey Bay have slowed over the past couple of weeks. Residents say this period is usually quiet for whales as we await the first major movement of subadult whales in late March."

Lucy S. Vlietstra, Monterey Bay, California

Field Report From Loon Wintering Grounds in Florida

To: Journey North
From: Joe Kaplan
and Keren Tischler

March 9, 1998
Since we last wrote, we looked at over 40 loons brought to the Suncoast Seabird Sanctuary, a bird rehabilitation center near Tampa Bay. These loons were very interesting as they were of various ages and degrees of molt. Many of them appeared to be adults (in contrast to the few adult loons we examined in the Ft. Lauderdale area) and were in the early stages of attaining alternate (breeding) plumage. It seems that the wing coverts which cover the flight feathers, and the scapular feathers, located along the body where the wing attaches, are among the first areas of the bird to molt. Most of the adults were also in the process of growing in a new set of flight feathers. Since loons molt their flight feathers simultaneously, these birds were flightless when they were found.

Currently, we are at the Crystal River National Wildlife Refuge in Citrus County on the northwest coast where we are working with Ted Ondler, the Assistant Refuge Manager, to capture what we hope are healthy loons. Crystal River is the well known home of the Manatee which congregate here in winter around warm fresh-water springs. Loons must like it too, because we have captured nine over the past two nights and have seen a big group of 20 loons rafting together at night!

Four of the loons we captured were adults and have a complete new set of flight feathers. This means they will soon be ready to begin their migration north. Of course, these loons still need to replace body feathers to acquire the plumage they will take back to the inland lakes for breeding. It appears that the head is the last part of the bird to molt and, in fact, we occasionally see loons in early spring with a little winter white in their faces--usually on their throats (not to be confused with the white chin feathers which are part of the breeding dress). Loon observers south of the breeding areas should check to see if they can spot loons that haven't finished molting. Once or twice a season a loon without any adult features (i.e. in winter plumage) will appear on a breeding territory, but these loons are not seen for long before they leave.

Hopefully, by the next time you hear from us, many of these loons will be in breeding plumage and will be initiating migration. We are excited to watch the changes.

Joe Kaplan and Keren Tischler
Biodiversity, Inc.

Are You Ready For Their Arrival and Challenge Question # 3 ?

Photo: Dr. F.G. Irwin

Now that you have read the Biologists Field Reports, take a look at a field guide to get yourself ready to identify the loons, and to answer the Challenge Question. It's time to sharpen your observation skills.

You'll need a Field Guide to North American Birds. Although they're called Common Loons, they are not commonly seen by most people. At first glance, many birds may appear the same. Look more closely and read the information carefully. To identify a bird correctly you must consider such things as its: size, shape, colors, markings, vocalization, the bird's location and even its behavior!

Now, look closely at the face of the loon pictured here, consider the Field Reports above, and see if you can answer:

Challenge Question # 3
"At what time of year was this picture taken, and how do you know?
There are 2 clues in the picture; can you name them both?

(To respond to this Challenge Question, please follow the instructions at the end of this report.)

How to Track Loon Migration

Please report the FIRST loon you see this spring to Journey North!

Please report your FIRST loon of the season to Journey North.

If loons over-winter in your region, please report your "FIRST" loon NOW. We'll know by the date that your sighting was pre-migration. (Since our computer can't add an extra category for "over-wintering" sightings, we ask that you report these as "FIRST" sightings.)

Scientists Discuss Challenge Question # 1

Feather and blood samples

The goal of Keren and Joe's work is to figure out when and where mercury (Hg) gets into the loons' blood. Because feathers are grown at a known time of year, they are like a snapshot in time.

In our last report, we asked: "If feathers can be collected from loons at different stages of maturity, what do you think they might help the biologist to understand?"

Students from Minnesota gave their answer, and Scientists Joe Kaplan and Keren Tischler explain their thoughts below.
"We think the answer to challenge question # 1 is to look for chemicals like mercury."
Megan and Shannon
4th grade, Jim Minerich Peguot Lakes School, Pequot Lakes,MN

Keren Tischler explains: "Understanding how loons mature through molt (replacing feathers) is poorly understood but very important to our understanding of how contaminants accumulate in these animals.

"Using feather mercury values from hatch year loons found in the winter, we can hopefully extrapolate what the blood mercury level was at the time the bird fledged. Mercury tested in these feathers indicates the levels the young loon had on its natal lake in the north. Then, with a new blood sample, we can determine changes in the amount of mercury found in blood since the bird has been on the ocean. An additional bonus is that many of the young loons have already begun replacing feathers, so we can compare old and new feathers and determine the changes in mercury over the last 4-5 months. We will do the same thing with 2-3 year old loons that have spent at least a year on the ocean. (Remember, loons take 3 years to sexually mature before they molt into the definitive breeding plumage and return to the north to nest.)

"Eventually we would like to develop an exposure model of Hg that can account for year-round accumulation of Hg from both the summer and winter territories," says Joe.

"We are also planning to do similar work with Belted Kingfisher. The EPA has identified the kingfisher as a species at risk for Hg exposure. Southern Florida (i.e. Everglades National Park) has some of the highest Hg levels in the country. The advantage of working with kingfishers is they are more widespread in distribution and are more tolerant of people so, they can be found closer to industrial areas potentially higher in Hg contamination than the loon. It is a way to cover more territory as we try to develop a geographical perspective of Hg exposure in North America."

Challenge Question # 4

Photo: Dr. F.G. Irwin

While Biologists Joe and Keren continue to focus on when and where the mercury gets into the loons' systems, try to focus your efforts on:

Challenge Question # 4
"How do you think mercury gets into a loon's body? That is, describe step by step how mercury from the atmosphere might end up in a loon?"

(To respond to this Challenge Question, please follow the instructions at the end of this report.)

Journey North Observer Concerned about Beached Loons in Florida

To: Journey North
From: Francis Harvey

"I am from Canada, visiting Panama City Beach, Florida. Each day, I walk the beach and for the past three weeks I have marvelled at the common loons playing in the surf. Now, during the past five days, there are no loons in the surf - just dead loons on the beach. Why?? What is killing them?? Yesterday, there were two dead loons on Panama City Beach. On Monday, there were 3 dead loons, and last week there was one dead loon. I have reported this to the Panama City News Herald and to Channel 7 News."

"My concern is that when I go home to Canada and go fishing in the summer, I may not hear these magnificent creatures yodelling across the Rideau Lakes where there are about 14 or 15 nesting pairs each summer. I like loons. Why are they dying on Panama City Beach??"
Smiths Falls, ON, Canada K7A4S4

We forwarded this note to biologist Dave Evers. Here are his comments:

"I'll talk to Joe and Keren about this and see if they can get up there soon. They're at the Ding Darling NWR and are slowly making their way into the panhandle of FL. That area is where there was an estimated 2,500 to 10,000 loons that died in the winter of 1982-83. That die-off was strongly linked with mercury."

"It's hard to say right now why loons are dying there, but there is also a dieoff going on off the coast of NC per Stephanie of the Outer Banks Wildlife Shelter. Maybe you can get some sort of network going and we can find out how many loons are being found on beaches around the country."

"There are several studies that have shown the period of molt to be very stressful and energy consuming for birds. Loons are flightless for about 2-3 weeks while their new feathers develop. This is the time when loons are in greatest danger. Not only are they unable to fly, but they must expend significant energy to grow feathers. (There are 11 primary feathers and 22-23 secondary feathers on each wing-- that's a lot of feathers and they're big!) Since they are using their energy stores they are less able to deal with diseases at this time. When the molt is finished, they have brand new feathers for their trip north."

"Loons may especially be vulnerable due to the synchronous remigial molt (i.e., all the flight feathers are growing in at once). The 1982-83 dieoff occurred during wing molt of the local population. There may be a link to mercury. Methylmercury is bound up in the muscle tissue of loons, particularly those individuals that have accumulated a lot of it during the breeding season. During stressful times, like a wing molt, a lot of energy is needed to grow in the new feathers and methylmercury can be remobilized from the muscle tissue into the blood and subject the loon (i.e., its brain) to high levels of mercury."

How to Respond to Journey North Loon Challenge Questions:

Please answer ONLY ONE question in each e-mail message:

1. Address an e-mail message to:

2. In the Subject Line of your message write: Challenge Question # 3 (OR # 4)

3. In the body of the EACH message, give your answer the questions above.

The Next Loon Migration Update will Be Posted on March 26, 1998.

Copyright 1998 Journey North. All Rights Reserved.