DDOT Director Terry Bellamy, right, speaks with Ali Shakeri, DDOT’s program and project manager, in a 2011 photo. (Sarah L. Voisin/The Washington Post)

The leaders of two major District government agencies have announced they are leaving their posts in the near future, the first signs of a “brain drain” for lame-duck Mayor Vincent C. Gray (D).

Transportation director Terry Bellamy and the department’s chief engineer, Ronaldo “Nick” Nicholson, have announced their intention to depart before the end of the month, according to two city officials familiar with their decision. Those officials spoke on the condition of anonymity because they were not authorized to speak publicly about personnel matters; a transportation department spokesman, Reggie Sanders, declined to comment Tuesday morning.

Also departing is Nicholas Majett, director of the Department of Consumer and Regulatory Affairs, which handles a broad array of permitting and licensing functions. Majett said Tuesday he will assume a “high-level” post for Prince George’s County Executive Rushern Baker in early May. His departure was first reported Monday by Washington City Paper.

“I think I can go to Prince George’s County and make a difference there like I did in the District,” Majett said. “I don’t think I can do much more in D.C. We’ve automated a lot things, the culture has changed, permits are issued faster, licences are easier to get. I’m not leaving anything undone.”

The move to Prince George’s has been in the works for months, Majett said, and had nothing to do with Gray’s loss in the Democratic primary last week. “That wasn’t one iota of a factor,” he said.

Regardless of the reasons for the exodus, the departures are likely to mean two crucial city departments will remain without a stable leader for months, thanks to the unprecedented nine-month lame duck period.

D.C. Council member Mary M. Cheh (D-Ward 3), who oversees the sprawling transportation department, said she was disappointed by the departures of Bellamy and Nicholson.

“We’re going to have headless agencies, she said. “It’s a kind of disruption I was hoping we could avoid. It doesn’t help to have drift in these agencies for half a year. … We’re seeing the consequences of a long lame-duck period.”

Democratic mayoral nominee and council member Muriel Bowser (D-Ward 4) said she was not surprised by the departures, noting that other Cabinet officials including city planner Harriet Tregoning and employment services director Lisa M. Mallory have already taken their leave. “They’ve been bleeding people for a while,” she said.

As for how Bowser expects Gray to proceed with his appointments, she said, “I expect that he’ll put somebody competent in acting positions and give the new mayor an opportunity for a fresh start in those agencies.”