Nick
I am back living in the woods
A pair of sapsuckers is nesting nearby
they routinely make wierd screams
not sure what the function is
other then to wake me up

Narendara
Many duck species
pair up before arriving at the nesting grounds
even though a hen was not present
the squabbling drakes may have been establishing dominance
so when a hen shows up, the dominant will have an advantage
also, you observed that bubbleheads frequent your lake
perahaps the victorious male wanted to stakeout the joint
since it is a likely habitat
where females move through

fred S