Pil-wil-willet

I spent some time at daybreak this morning at Tiscornia.  There was virtually no movement in the calm air with a storm front slowly approaching.  The one exception was a flock of seven (!) willets that flew in and landed on the beach in front of me.  They did indeed sound similar to yellowlegs though their voices were lower and seemed to carry more.  Once they landed the adult bird (there was one adult bird and 6 juvies) continued to give calls different from the flight call which were essentially variations of a descending pill! or pill-ill! which seemed somewhat intermediate between yellowlegs calls and the ring-billed gulls'.

Here's one of the juvies:

You can see that it has very fresh feathers with pale edgings, as well as numerous feathers in teh wing coverts and scapulars that slowly increase in size rather than being basically all one size like the adults have.  Aging a shorebird is a critical first step to identifying it as in a great many species, the juveniles will look more like hte juveniles or other species than they will the adults of their own species (such as in most of the peeps and the larger calidrid sandpipers like stilt sandpiper or dowitchers).  

The adult in contrast has very worn ratty plumage this time of year:
Most of the pale coloration has worn off and the dark pigments have darkened somewhat.  Some of the feathers are essentially worn down to their barbs.  Obviously there was originally a different pattern to many of the upperparts feathers as well.

Just for completeness sake here's a full winter plumaged bird from Florida (I'm not sure if it's the eastern or western subspecies; western is the version that migrates through Michigan):