A WHAT sort of Pidjin?

Found lurking in the vicinity of Lloyds Bank.

Poor thing was sufficiently "Paggered" it was relatively easy to catch. Got home and discovered , not the usual metal ring + "Racing Ring", it had three, apparently all of them metal, one curled on after adulthood at a guess. That one said "If found telephone ***********" So I did.
At which point I discovered the existence of "Roller Pigeons".
Which kinda begs the question ...
WHY would they?

One GOOD thing about them, you'll need to bother a lot less about them blending in so that raptors don't notice them as easily. This one was quite evenly marked AND quite bonny, after I got a decent look at it.
It said "Birmingham roller Super performance "