Two national polls have been conducting nightly surveys since the former North Carolina senator departed the race, and both show his supporters moving more to Obama than Clinton. First, Gallup:
Gallup Poll Daily tracking shows Hillary Clinton and Barack Obama as close as they have been since the polling program started at the beginning of 2008. Forty-four percent of Democratic voters nationwide support Clinton, while 41% support Obama, within the poll's three-point margin of error. The data suggest that Obama has gained slightly more -- at least initially -- from John Edwards' departure from the race. In the final tracking data including Edwards in all three days' interviewing (Jan. 27-29 data), Clinton had 42%, Obama 36%, and Edwards 12%. Since then, Clinton's support has increased two points and Obama's five.
And, Rasmussen:
The Rasmussen Reports daily Presidential Tracking Poll for Friday shows Barack Obama inching closer to Hillary Clinton. It’s now Clinton 43%, Obama 37%. A week ago, Clinton had an eleven point advantage, 41% to 30%. The last two nights of tracking were the first without John Edwards in the race. For those two nights, it’s Clinton 44% and Obama 42% meaning that Clinton’s support is essentially unchanged. This suggests that many former Edwards supporters now support Obama, many others have yet to make a decision, and few currently support Clinton.