I use 2 feet high wire fencing around all my garden beds. They're short enough to reach over and rabbits won't jump over them. Until last year, I used 1"x2" opening but found out that the baby bunnies can hop through and baby groundHOGS can squeeze through.
I'm using 1"x1" and 1" hex chickenwire this year.
They say you should bury the bottom 4~6 inches, but I haven't done this. I'll add an extension if I have to. Adult groundHOGs WILL climb over 2' fence though. I'm contemplating electric hot wire. Haven't decided yet because I usually step over these fences even though I've built little gates into the garden paths....
Blackbirds -- we get migrating flocks coming around too. So far, they haven't bothered my garden. Last year, I covered corn and sunflowers with tunnel covers until they outgrew them since I read that blackbirds peck out the seeds -- helped to keep the rabbits out too (they LOVE sunflower seedlings
) In the summer, they usually bring their fledglings and congregate around the bird feeder and take over the bird bath shooing off all the PRETTY birds.
One thing -- the deer fencing -- I've tried using that to keep out the groundHOGs -- they rip holes in them, then rabbits and birds (catbirds going after blueberries) get in and can't figure out how to get out! One year, I used berry netting (thinner plastic strands than deer fencing) and a young bunny got entangled in it -- screaming it's head off. Was not a pretty sight.