A drive to cull ducks has begun at the famous Sanjay Lake, where several ducks were found dead in the last few days, Singh added. Seventeen more ducks were found dead at Sanjay Lake on Sunday, prompting authorities to declare it an "alert zone", DDA officials had said. Besides, the officials said, 91 crows have been found dead in 14 DDA parks in the last couple of days. A few days ago, around 50 crows were found dead in Central Park, Mayur Vihar Phase 3, officials had said. Some samples were also sent to a lab in Jalandhar. Their results are awaited, Singh said.