At the Middletown, Maryland Middletown Community Park off Coblentz Road in Frederick County on a VERY cold Sunday (26 FEB) at an unfrozen grassy “swamp” adjacent to the park road, I observed two Killdeer engaging what appeared to be courtship behavior.  

Jim Speicher
Jspeicher—at—niaid.nih.gov
Rockville @work :(
Broad Run_S. FRED Co @home :)