Thursday, September 9, 2010 11:08pm CDT

 
57 degrees   Light Rain   Calm
 
After so many days of heat and humidity over the last couple months, there is definitely a feel of fall in the air.  Chilly fog filled mornings.  Grass covered with heavy dew.  And we are almost to the autumnal equinox when we have 12 hours of daylight and 12 hours of night.
 
The days change so quickly at this time of year.  Where only a month or two ago, it was not dark until almost 10 o'clock, now it is dark by 8pm.
 
Along with all the other signs, the fall migration has begun.  Delicate beautiful monarch butterflies are on their phenomenal journey of over a thousand miles.  I have not seen any orioles at the jelly feeder for a couple weeks so I assume that they are on their way as well.
 
And our loons.
 
I have not seen nor heard them for several weeks.  I have been gone a lot and not had much chance to be out on the lake, but I would have expected to see or hear them at some point.  So I have to assume that they are also preparing to fly south.
 
Normally loons will gather in large groups called 'rafts' as they prepare to begin their fall migration.  They gather on large  large lakes called staging lakes.  These may be some of the larger lakes in the area or they may be one of the Great Lakes.  The Great Lakes are a apparently a major area for the gathering of loons.  But there is so much that is unknown about loon's migration patterns and needs and about their wintering habitat and behavior.
 
That is one of the reasons for the study that Kevin Kenow from the US Geological Service is doing on the migration of loons.  The original purpose of the study was to try to determine how and where loons were picking up the botulism toxin that has killed so many over the last ten years.  There have been upwards of 80,000 water birds killed on the Great Lakes and several thousand loons have been killed by botulism.
 
As I have mentioned before, I was privileged to be a part of the team that captured some Minnesota loons for the study.  We surgically implanted satellite transmitters in two loons which will allow them to be tracked as they migrate south this fall as well as when they migrate north next spring.  Eight loons in Wisconsin were also implanted with these satellite transmitters as well as 80 loons in Minnesota and Wisconsin that were outfitted with data recorders on their legs that will record where they migrate as well as how deep they dive.
 
All of this information will help to try to determine how they are picking up the botulism that is killing them.
 
You are probably familiar with "botox" which is used for cosmetic surgery.  Botox is the same botulism toxin that is killing loons.  In small quantities that are used in cosmetic surgery, the botox paralyzes facial muscles that cause wrinkles in the skin.
 
But in larger quantities in a loon, the botulism toxin causes muscle paralysis....especially of the neck muscles of the loon.  The loon is then not able to hold its head up and it drowns.
 
Some of you are already aware that sadly one of the two loons in which we implanted a satellite transmitter was found dead on Lake Michigan.
 
He left his home lake on the St John's campus earlier than any of us expected.  He was tracked by satellite travelling over to Lake Michigan.  So far there was no cause for great concern.
 
But then one day, the satellite data showed a low body temperature of 21 degrees Centigrade (about 70 degrees).  Kevin tracked the satellite data throughout the day as the loon drifted to the SSE on Green Bay of Lake Michigan.  He drove all the way over there and was able to find the loon on the shore.  Unfortunately it was dead.
 
The big concern was what had killed it.  Was it a casualty of botulism?  Or had something else happened?
 
A necropsy done by the National Wildlife Health Center since then has determined that the loon probably died from "chronic severe respiratory and systemic aspergillosis".  We have talked about aspergillosis (just called asper for short) before.  Loons especially do not do well in captivity.  When under stress of captivity they tend to develop asper.  This is true of some other birds as well but loons seem to be especially susceptible.
 
There are other tests being done on the air sacs of the loon's lungs for fungal cultures to try to determine more information of what happened with this particular loon.
 
A couple people have asked me if the death could be related to the surgical implanting of the satellite transmitter.  That is always an area of concern when you do something like that.  But the good news is that it did not have anything to do with it.
 
First of all, the death was a month-and-a-half after the capture of the loon and the implant surgery.  If there had been a direct connection, you would expect that it would have happened much closer to the time of the capture.  So that argues against a direct connection.
 
But also the necropsy showed that the tissues around the implant had healed and "did not appear to be adversely affected".  So that argues against the surgery and the implant having had a negative effect on the loon.
 
So now we await further information from the necropsy to find out what actually happened with this particular loon.  And hopefully we can learn from this unfortunate event.
 
I have been told that the link to track the loons by satellite hopefully will go live next week.  As soon as I have any information about it, I will try to give you a link.  And then you can track the loons yourself as they head south this fall.  How exciting will that be!
 
This part of the study will help us understand what route our loons take to their wintering grounds and what happens to them when they get there.  In light of the Gulf oil spill, this information takes on added urgency.
 
The best information that we have now is that loons from the Upper Midwest and central Canada may go equally to the Atlantic Coast and the Gulf of Mexico.  This would be one year where it would be nice if ALL of them went to the Atlantic Coast.  But we shall see what the satellite data tells us.  And you can be a part of observing this first hand!
 
Most of the loons from New England and eastern Canada go to the Atlantic Coast from Nova Scotia down to North Carolina.  So they should be safe from the Gulf oil spill.
 
There continues to be relatively good news coming out of the Gulf.  Most of the oil has "disappeared".  Now we know that it has not disappeared but at least it is not causing the major problems that had been forecast.  No one has a definitive answer yet about what has happened to it.  But it is thought and hoped that microbes in the Gulf have been eating it and 'neutralizing' it.  Let us hope that turns out to be the case and that the negative impact has been greatly diminished.  That would be wonderful news for our loons.
 
So right now loons all across the northern tier of states and Canada are now  gathering and beginning their migration south.  Typically the adults leave sometime between the middle of September and the middle of October.
 
Then in one of the many miracles of nature the young from this year leave about a month later and migrate from the middle of October to the middle of November.   Having never been to the Gulf or the Atlantic, they find their way on their own.  Another one of the miracles of nature that we do not understand at all.
 
So soon the great north country once again falls silent without the magical calls of the loons.
 
All through the winter we have only our memories to carry us through the silent months as we await the return of our loons next spring.  What will the spring hold for us and for the loons.  There is no way of knowing.  All we can do is wait and hope.
 
And then on that day that the ice goes out of our northern lakes, the wonder and excitement that we feel when we once again hear that first call of the loon.  That magical sound that stirs something so deep within us that it is even hard to describe.
 
The sound of the north!