One Tough Bird

We've had a pair of resident sandhill cranes nesting here for as long as we've had our big pond; making it thirty years.  I don't believe it has been the same pair for the duration ; nevertheless, we've been witness to cranes arriving here in the month of March is some remarkably harsh weather conditions.  Including Winter Storm Elsa which ended late Monday.  Our cranes have been here for a couple of weeks already and when I arose yesterday they were easy to spot given all the snow on the ground.

There they were - several hundred yards north of the house - at the edge of the frozen pond, in a couple feet of snow, on a sunny 18F morning.  The sandhill is an incredibly hardy critter always arriving at their northern breeding grounds while there is still snow covering icy wetlands. 

This bird comes factory-equipped with some sophisticated physiological adaptations that allow it to thrive under the harshest of conditions.  One of these is a sophisticated network of blood vessels in their legs called rete tibiotarsale.  Also found in penguins and turkey vultures this allows warmer arterial blood from their heart to transfer heat to the cold venous blood returning from their feet.  This keeps their core temperature warm while allowing their feet to remain at a lower temperature while standing in snow or icy water.  

When airborne cranes typically fly with their long legs trailing behind.  If it is too cold at 10,000 feet of altitude the bird will tuck their legs into their belly feathers to conserve heat.  Speaking of which, the crane's plumage is a dense layer of soft downy feathers beneath an outer layer of contour feathers.  Air trapped by the inner layer provides thermal insulation beneath the outer feathers that repel wind and freezing rain.   

Crane behavior strategies include the use of tail winds to speed their migration from Mexico and southern states, roosting in warmer waters adjacent to power plants and preening their gray feathers with mud to make a rusty-brown camouflage to hide from predators.  Until the arrival of spring green-up, this is a bird capable of digging beneath snow to locate waste grain in agricultural fields and tubers and dormant invertebrates and amphibians in frozen mud. 

Anyway, we're looking forward to observing the ritual mating dance of Wisconsin's tallest bird.  The birds will face each other, bow and jump while flapping their wings and making loud cackling calls.  Yes, this tough bird can dance too.

Stay-tuned for any lucky trail camera photos I might capture this season.