The bird dropped some bread on a section of outdoor machinery, eventually leading to significant over heating in parts of the accelerator. The LHC was not operational at the time of the incident, but the spike produced so much heat that had the beam been on, automatic failsafes would have shut down the machine.
The LHC is scheduled to be reactivated later this month. The bread incident won't affect those plans. http://www.popsci.com/science/article/2009-11/bread-loving-bird-shuts-down-lhc -via Boing Boing