Sunday, May 9, 2010 5:18am CDT

 
27 degrees   Clear    Wind Calm
 
Morning comes for our loons.
 
The other birds in an increasing crescendo have begun their morning chorus.  Miles away in the clear, cold morning air the plaintive sound of the train whistle echoes across the lake as one of our loons sits faithfully on the nest protecting its precious cargo.
 
The other loon swims peacefully nearby.  It isn't time for the nest change yet.  But it will be soon.  The first glimmers of dawn are starting to brighten the eastern sky.
 
The weatherman's prediction of a freeze warning has come true!
 
It is only 27 degrees right now.  It will be another half hour before the sun even peeks it head above the horizon.  And then another hour or two before it is high enough to begin warming the chill morning air.  In fact, the temperature may very well drop a degree or two before that happens!
 
There is a lot of frost visible on the nest around the loon.
 
But underneath her, everything is as toasty and warm as you could ever want.  And she makes sure that she keeps the eggs covered and protected from the frost.  Her body and her wings and her tail make a perfect cocoon that protects the eggs from even a draft.
 
Most birds have a bare patch of skin on the breast.  When they are incubating eggs, they can spread the feathers so that the warm, bare skin is pressed against the eggs to keep them warm.
 
Loons do not have this patch of bare skin which is called a 'brood patch'.
 
Instead, towards the back of their abdomen, in the  whole area of the belly that rests on the eggs, they have an increased blood supply which keeps the eggs warm.  Yet one more of the unique things about these special birds.  And so each time the loon gets on the nest, it will not only roll the eggs but it will also position them towards the back of its abdomen to that place where there is increased warmth for them.
 
You can see the effect of this warmth this morning as the frost comes almost up to the loon.  But there is a narrow band around the loon that is free of frost because of this extra warmth.
 
Even though the loons share nesting duties fairly equally, research has shown that the female spends about 60% of the time on the nest.  And she is the one who usually takes the long 'night shift'.
 
So I assume it is her on the nest now although it is impossible to tell since their appearance is almost identical.  Soon there will probably be a nest change and she will be able to get some much needed exercise.
 
But until she decides it is time and her mate is ready to get on the nest, she sits faithfully on the nest.  As far as the eggs are concerned, it could be a 75 degree day.  They have no idea of the frost that surrounds them on the nest this morning!
 

Saturday, May 8, 2010 11:07pm CDT

 
It is going to be another cold night for the loons.
 
It is already down to 34 degrees right now and going lower.  There is a freeze warning for a good share of the state of Minnesota.  We are almost guaranteed to get below freezing here.  The official freeze warning from the US Weather Service is from 3 am to 9 am.
 
But at least there is not snow and howling winds like last night.  Tonight is very quiet.  The lake is almost like a sheet of glass and the lights from across the lake are reflected in its surface.
 
So if intruder loons and muskrats and other things that go bump in the night do not scare the loon off the nest, the eggs should make it through the night with no problem.
 
I saw there was some discussion of how long the eggs could be uncovered without being harmed and that the number 6 to 8 hours was quoted.  That figure would probably be true for more seasonable temperatures or daytime temperatures.  With the temperature below freezing, I think they would be harmed much sooner but am not aware of any hard research that would give what that time would be.
 
It would also vary at what stage of development the egg was.  Early on before the embryo has begun to develop very much, they can stand more time uncovered but definitely not freezing.  Then when the chick is more fully developed, it generates some of its own heat so it can also stand more time uncovered.  Probably the most vulnerable time is that mid stage of development.
 
Right now, it is quiet.  The loon is firmly ensconced on the nest.  We can only hope that nothing draws her off the nest during the night!  Here is to a quiet night for you, dear loons!
 

Saturday, May 8, 2010 6:47am CDT

 
You are watching right now one of the dangers to loons hatching their eggs! 
 
The female loon got off the nest without the male in sight.  For some reason, she doesn't seem to be overly concerned to head back to the nest but she does have her head held very high.
 
At first it is if she is looking for the male. 
 
She swims back to the nest and preens, but does not get on the nest.  Then she swims back out. 
 
It is then that I see her and the male swimming together with heads held very high.  What are they concerned about.  There is no calling however.
 
THERE it is!  The object of their concern.
 
There is a third loon in the area!
 
An intruder loon that they are concerned about.  It is now 20 minutes that she has been off the nest leaving the eggs exposed to the cold!

Saturday, May 8, 2010 5:48am CDT

 

32 degrees  Cloudy   Wind NW13mph

 

The yodel of a male loon pierces the cold morning air and echoes around the lake.

Wisps of fog race across the surface of the water, driven by the wind under a leaden gray sky.  The cold bites through.

This certainly can't be mid-May!  Only days ago it was in the mid-80s.  Now it feels like February again.

Then another yodel from the male who is sitting some distance away from the nest overpowers the sound of the wind.  There is no other loon apparent that he seems to be challenging.  There is no other predator that is obvious.  There is no other eagle flying overhead.

It is as if he is shouting into the  sharp cold wind that 'it will take more than this to defeat us'!

And then from the nest the female answers with an undulating wail!  She agrees, too.  She is not defeated.  It will take more than a little cold and snow and rain and wind to make her give up on her mission.  She is firmly ensconced on her eggs.

Last night in the snow she laid the second egg.

They now have the two that they will incubate for the next four weeks.  A third egg is unlikely.  And probably unnecessary.

All night long she sat protecting those two precious eggs.  Keeping them warm.  Sheltered from the rain and snow and wind and cold.

She rises up on her legs and looks down at the two large brown mottled eggs and turns them with her beak.  She settles back down on them taking care to get them just right.  Rocking back and forth until she is sure that she has them covered completely.

Then she lowers her wings around the sides of them and locks the tips of her wings under her tail.  No north wind is going to sneak through and get to her eggs.  They are as snug and warm as they would be on a day with sunshine and 75 degrees!