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!