American Avocet
Recurvirostra americana
The American Avocet is one of those birds that has distinctly different plumages during the year. The photograph above was taken on July 26, 2010 at Elkhorn Slough, CA. They appear to be mostly in their non-breeding plumage, generally occurring from September-March (a careful look at the head and neck in the photo shows the buffy-orange breeding coloration is going but not totally gone).
This photograph shows the breeding plumage of the American Avocet, the buffy-orange coloration of the head, neck and throat. This generally is present in the adults from March-August, and this photograph was taken on March 1, 2014.
This photograph, taken on the same day as the above one, shows that the younger birds don't develop breeding plumages until, well, they are ready to breed! Most start breeding after age 2, although a few start somewhat earlier.