What is this bird doing, and why?

Factual Questions
1

So outside the kitchen at work, there’s a large bush in which lives a mockingbird. When the kitchen workers park their cars nearby, the bird spends hours pecking at the side mirrors. It will perch atop a mirror, then jump down to the door frame, peck the mirror, and then hop back up to perch on the mirror for another few seconds. Repeat. Repeat. Repeat until the kitchen workers go home.

So, what is the bird doing? The current guesses around the office are that it’s either trying to have sex with itself, or it’s trying to drive itself away from its territory. Not having an ornithologist handy, I turn to the Straight Dope.

Of course, all the while the bird is pecking mirrors, the bird is also pooping all over the car, and scratching any plastic parts (like the side mirror housings on newer cars) with its little claws. It has also been known to run across a sunroof, pecking away like mad at the glass, leaving blobs of birdcrap behind.

It’s been doing this for the past five months or so. Before then (and I mean for the previous couple of years), it (or other birds just like it) would occasionally spend some time (minutes, not hours) pecking at the tinted, mirror-like windows of the building itself. But not nearly with such intensity as this particular bird goes after these side mirrors.

Paper plates taped over the cars’ side mirrors prevented this behaviour, but was too much of a hassle. Clear plastic bags tied loosely around the mirrors didn’t stop the bird at all, but did save the mirrors themselves from poop. One woman had a big SUV with foldable side mirrors, but she told me that folding the mirrors in just made the mess worse, as they didn’t fold in enough to prevent the bird from getting between the mirror and the window, and the bird’s flapping wings in the narrow space spread its poop everywhere.

While we’ve gotten plenty of use out of the bird as a joke (that it exemplifies the term “bird brained” very well), the kitchen workers are damn tired of it. I’ve been thinking about getting a decently-sized hand mirror and hanging it from a branch in the bird’s bush, but am slightly concerned that the bird might exhaust itself given a mirror to peck at during all daylight hours, instead of just the two or three hours it does so now, while the kitchen workers are parked near its home.

Also, since the bird doesn’t always pick the car nearest to its bush, I think it probable that a mirror in the bush itself won’t actually stop the defiling of the vehicles.

Perhaps needless to say, the people around here are reluctant to harm the bird (although BB guns have been jokingly discussed). Any suggestions of how to reduce or prevent this behaviour (at least in relation to the cars, I couldn’t care less about the building) would be appreciated.

2

From here:

Not very helpful, sorry. I’d just shoot the fucker.

3

The bird is trying to drive a rival mockingbird off its territory; it sees its reflection in the mirror and thinks it’s another bird.

As far as I know, covering the mirros so the bird doesn’t see its reflection or doing something to frighen the bird completely away (which won’t be easy to do) is the only way to deal with this problem.

4

My guess is that it’s driving away potential adversaries. Those damned birds in the mirrors only show up when the cars do, right? Obviously they’re coming with the cars. AND THEY WON’T GO AWAY! Not until the evening, when the cars drive off. Just imagine if he hadn’t been pecking at them all day – they might still be there.
This reminds me of the time I interviewed for a job in a building with mirrored glass walls. In the middle of the interview a bird walks up and starts pecking at its reflection in the mirrored glass, and kept it up for the rest of the interview. I was told that it did this every day. We’re all pretty certain it was another case of the bird establishing its territory against the “bird in the mirror”. And this bird didn’t even have the positive reinforcement caused by HIS bird running away at the end of each day.

5

I once raised about a dozen bob white quail from eggs. Sadly, all but one died in a late spring ice storm. We let the one that lived run loose around the place. We named him Bobby, of course. When he grew up he would look at himself in the truck’s hub caps and give his sharp “bob white” whistle. We always felt sorry for the little guy, thinking he was looking for a girl friend.

6

I have a cardinal in a tree by my driveway that does that. We’ve given up and now park the cars at the other end of the driveway.

7

Birds do this with mirror surfaces. With pet birds, you provide mirrors so the poor thing doesn’t go crazy-bored. This wild bird, however, is a nuisance.

You actually have half the answer in your OP - clear plastic bags don’t stop it, because they don’t stop the reflection. Use opaque plastic bags. You know, like those ubiquitous beige plastic bags you get at grocery stores. Couple of cheap rubber bands to hold them in place, and that should do the trick. At least for the side mirrors. AND provide bird-poop protection.

Try it and let us know how it works.

8

Well, coincidental to my asking about the bird here (thanks, everyone), one of the kitchen workers has started taping paper napkins around her side mirrors. It’s certainly cut down on the filth, but the bird is still wandering around on the roof of her car, leaving poop in his wake.

Perhaps if everyone who pulled in to that particular section of parking lot covered their mirrors, the bird would take interest in the building windows again, and forget about the cars, but the problem appears to be that the bird will go after any vehicle pulling in, including delivery vans and even Pepsi trucks.

I’m guessing that the bird ignored vehicles for (possibly) years before this simply because it didn’t know about the mirrors on them. Perhaps, quite by accident, it discovered them last October. And since they’re much more reflective than either building or car windows, it now goes after the mirrors preferentially.

Luckily, I don’t park down there. I’m just trying to help out the folks who do.