What kind of birds are they? Birds are good, they eat the bad things. But I can imagine the "damage" that a whole slew of any kind of birds would do if they showed up all at once. The only time that ever happens is for a few days at the end of August. That's when the blackbirds or grackels come. But they fly away at the slightest sound. And again, I'm sure they're eating something I don't want in my garden anyways. But if you have other, common birds hanging out all the time, check out what you are feeding them. Lots of fruit bearing bushes? Birdfeeders? Seed filled flowers, like sunflowers and coneflowers?

It's probably birds coming through on migration; they'll leave before long, but that doesn't help you much while they're there. The bad news is migrating birds are difficult to get rid of if they've decided to use your yard as a resting place. The good news is they won't be there that long because they're headed south. Making your yard unattractive to birds is about all you can do, and when you're talking whole flocks, that's really difficult.

I know you don't want to kill them and killing many birds is illegal anyway, because they're protected by law (some, like house sparrows, are not). A cat will irritate them a little but won't deter flocks. My dad used to take a gun with blanks outside and shoot it to make a huge noise to get rid of them when they stopped in our trees (the squawking made dinner conversation almost impossible) but that's only a temporary help -- they tend to come back. And even blanks can be dangerous, but if you're interested in that approach, think of something to make a loud noise (banging on a trash can or something). However, like I said, they tend to come back -- just ask officials who to try to keep birds off bridges, etc.

Throwing some mulch around won't destroy your beds, just mess them up, which is a pain but not permanent, so you should be able to repair that as soon as they leave. Try bird netting over your tomatoes and other plants they're eating. I don't have much else to offer but you also might want to post on the birding forum to see if they can help. Good luck, and take heart; like I said, they shouldn't be around too long.

Here is a link that might be useful: birding forum

If there are a lot, it means they are eating something. Are you sure you want them to stop eating whatever it is, perhaps a nasty insect? ;-)

Oh, if they are eating tomatoes and other juicy fruits, that's usually done for the water, so set out a pan of water for them, and the tomato eating might stop.

Bird poop makes good fertilizer. But, if they are using you benches and other seating areas, provide them with another choice. We have split rail fencing around our yard, so they perch there, not on my lawn furniture.

Sounds like Starlings too me. I usually have problems in the spring when they are looking for nesting material. Then they pull out a lot of seedlings. And are they Noisy! Damn that Shakespeare!

Here is a link that might be useful: Cornell

It's funny, because I invite birds in my yard by putting out various bird seeds and bath.
I've all types of plants, in which they don't bother..
The only pests I'm having problems w/are those darn squirrels..I detest them.
I don't recommend getting a cat for the sake of killing birds. Not only am I a bird lover but breed cockatiels. I also adore cats, but buying one for the sake of killing isn't right.
I detest squirrels but I wouldn't buy a preditor to rid those furry rodents..
Garden supply stores sell artifial animals w/sensors that hiss, swing, etc. This should be adequate. Toni