The MetroBus system is probably much safer than MetroRail, at least for the avian community of the District.

According to a recent article in the Washington Post, 16 pigeons were found dead outside of the Takoma Park metro station due to poison used nearby to keep pigeons and starlings from entering the stations.  The poison, placed in food near the station, has been used here and at other stops as a "last resort" for the seemingly overwhelming amounts of birds.

Maggie Brasted, director of the Humane Society's urban wildlife conflict resolution program, says that Metro "wants to bring [commuters and Metro] good practical solutions...We think that using poison is not very humane." 

Several years ago, a device known as the Beaver Deceiver was used to rid the area near a station of "troublesome beavers" by tricking them into believing that their dams were no longer working and "prompt[ing] them to leave."

Rumor has it that a similar device is being researched for the bird problem, but scientists are having trouble coming up with a word that rhymes with pigeon.