This was the longest Northern Mockingbird fight I think I ever witnessed. The last photo shows the one Mockingbird being held down for a 10 count.
Mockingbirds are territorial and they will attempt to defend their areas against other mockingbirds. The same sexes typically take each other on, with the males battling any male mockingbirds that cross into their territory and females trying to run off other females. The encounters between males can escalate into all-out fights with sparring birds deploying their claws and using their bills. Often, one of the birds will simply retreat to avoid a fight.
Read more: Mockingbirds & Aggressive Behavior | eHow.com