How long have they been there? I don't think of them as migratory, however wikipedia states some do. Also some will congregate in great numbers during winter months or breeding. I also don't think they actually stayed put for long. As mentioned, they are all over CO, i've seen them by my house too. They were gone after several months though. There are certain times of years when they are very thick in some SWA's, and that is why I was under the impression they don't necessarily stay put. The DOW usually puts out an press release when they are all congregating, however couldn't find it on their website.
Anyway, sorry for the ramble, but that may put the damper on having it a protected area.

