...Why can't they be pidgeons I could poison in the park?

For the last week or so, I've had a suicidal bird that's been hanging about my office window. For reference, I'm in an office area, and I have huge plate glass floor-to-ceiling windows next to my desk, and the ceilings go up about 10 feet in here.

Every day, in the same hour (around 9 am) there's a bird that flutters and hovers near the 9 foot mark at my window. The first day I just saw some movement out of the corner of my eye, and I thought it was a hummingbird and didn't look up quickly enough.

The second day I found that this was much larger than a hummingbird. It's your garden variety swallow of some sort, and it flutters at the window. That day it pecked at the window while still hovering there. Then it flew away.

I figured it was probably seeing some sort of reflection or something. The third day it fluttered once again. It hovered once again. It pecked once again. Then it flew away, and flew back rather quickly and bumped into the window. Then it flew away.

Yesterday was day 8. The birdie did all that it usually does, but flew with a little more force into the window. Maybe it was because of the power outage in the building, I don't know. It fell to the ground, picked itself up almost instantly, and flew away fast. I suspect that it's either really confused about what it's seeing in the window, or truly intent on killing itself. Or it's scared of it's own reflection based on the way it flies away so fast.

Of course, there's always the supposition that it's just trying to get into my office and get at the roasted shelled unsalted sunflower seeds that I keep there, but I doubt it. Those aren't even in plain sight of the window.

I would have expected it to have banged itself into oblivion by now, but this bird keeps hanging on. I'm assuming of course that it is one bird, but I find it really odd that I've not seen any birdie corpses lying outside my window...

...oh great, it could be a whole squadron of them.