USA Bus Lines - what are the Spike things on top of bus stops?

what are the Spike things on top of bus stops?

I see everyday on top of bus stop shelters, around (oval) thing wich has spickes out of them. Does anyone no what they are? thankz.

To stop birds nesting and therefore shitting on people at the bus stop.
probably to stop pigeons landing on them and crapping everywhere
Do these bus stops have interactive timetables? If so then it's probably the arial.
I think they are to keep birds from landing and pooping.
It's to shop the pigeons from doing their business all over the top of the shelter - nightmare to clean off.
Lighting conductors? Must be, they're the only conductors the buses have here in London now. . . . Bus stop art - spikes www.flickr.com/photos/dgbalancesrocks/143639184/ yeah, and if you're wondering who stole all our Routemasters, get a load of this. . . .1963 Routemaster in America. . . .what's it doing there. . . . . http://www.youtube.com/watch?v=LY47xrfFCeM&feature=related
stopping bird messing o people....OK
to stop hobos from nicking them