Birnbaum has only been head of the agency since July 2009 -- less time than her boss, Ken Salazar, has been secretary of the Interior Department, which oversees MMS. We've put in a call to MMS to confirm these reports.
It's also worth pointing out that just Wednesday, The New York Times ran a profile on Birnbaum, calling her "the oil spill's invisible woman." The Times noted that her background is mostly with environmental organizations, and when she took the top job at MMS, she "had virtually no experience with the oil and gas industry, but that was seen as a plus."
News of Birnbaum's departure follows the resignation of MMS associate director Chris Oynes, announced earlier this month.
We've been covering the troubles over at the Minerals Management Service for a while now. The agency's problems run the gamut, from lax regulation of "good friends" in the oil industry to recurring sex, drug and porn problems. Salazar has announced plans to shake up the structure of MMS to mitigate the agency's conflicts of interest, but many continue to question whether this move will be enough.