The Field Poll, set for release Tuesday, found 55 percent of likely voters support ousting Davis, down from 58 percent in an August poll. Forty percent said they opposed the recall, a gain of three percentage points from last month.
The poll, conducted over a five-day period ending Sunday, was drawn from telephone interviews with 505 likely voters. It has a margin of sampling error of plus-or minus 4.5 percentage points.
A month ago, recall front-runners Bustamante and Schwarzenegger were locked in a statistical dead heat, but Bustamante has since opened a small lead — 30 percent to 25 percent. Last month, Bustamante had 25 percent to Schwarzenegger's 22 percent.
In third place, Republican state Sen. Tom McClintock, the leading conservative in the race, was at 13 percent, a gain of four points.
Former baseball commissioner and businessman Peter Ueberroth garnered support from 5 percent of voters polled, columnist Arianna Huffington got 3 percent and Green Party candidate Peter Camejo was favored by 2 percent.
The results came just 30 days before the Oct. 7 vote, and as Bustamante, McClintock, Huffington and Camejo prepared to meet for the campaign's second debate Tuesday, sponsored by the Greenlining Institute.
Davis' campaign interpreted the results as a 6-point gain for the governor.
"We see support for the recall fading," said Gabriel Sanchez, a spokesman for the Davis camp.
Support for ousting Davis appeared to have grown incrementally since mid-April, before the election was official, when 46 percent of Field Poll respondents said they would vote for the recall. By mid-July, it was 51 percent, a number that grew again to 58 percent by the time of the August poll.
Schwarzenegger spokesman Todd Harris said Tuesday's poll showed that among candidates to replace Davis "this is a two-man race" and Schwarzenegger is the only Republican with a chance to win.
Schwarzenegger did not appear to have benefited significantly, however, from the departure of Republican Bill Simon from the race since the previous Field Poll. Simon had 8 percent support before dropping out.
And McClintock's solid, third-place showing underscored just how problematic his candidacy continues to be for Schwarzenegger. The legislator has steadfastly refused to step aside, even as Republican leaders have urged the party to unite behind the strongest candidate or risk a Bustamante victory.
At his first town hall-style meeting Monday, Schwarzenegger repeated his earlier comments that, mathematically speaking, it would be better for him if there were fewer candidates in the race. But he balked at a questioner's suggestion that he cut a deal with McClintock and perhaps offer the legislator a job in a Schwarzenegger administration to get him to quit the campaign.
"I'm not about to call him and say get out of the race," Schwarzenegger said.
The meeting at Chapman University was another step by the actor toward settling into the role of traditional political candidate. He took 16 questions over about 45 minutes from invited guests including members of GOP clubs, small-business owners and students. Topics ranged from women's issues to workers' compensation to water policy, with Schwarzenegger breaking little new ground.
On women's issues he expressed support for flexible hours and equal pay, while on immigration he repeated that he would seek to find a way to legalize the status of illegal immigrants, perhaps through a guest-worker program.
Also Monday, Schwarzenegger's wife Maria Shriver, who is taking a more public role in his campaign, was heckled by recall opponents as she toured a mall.
Davis, meanwhile, denounced the Republican recall backers during the latest in a series of town halls he's held in a bid to reconnect with Californians.
"The Republicans want to kick me out because of past problems. But they don't give a whit about past problems. They just want power. They want to steal the governorship on the eve of a presidential election," he told two-dozen people during a forum in Los Angeles' Crenshaw district.
On Monday, absentee voters had first crack at marking their ballots. With absentee voters expected to cast about one-third of recall ballots, campaigns courted them where they vote — their mailboxes.
Schwarzenegger sent out 2 million brochures and McClintock sent out 300,000. Schwarzenegger's message called for ending the "outrageous car tax," enacting a constitutional spending cap and making English the nation's official language.
Bustamante, meanwhile, continued to face scrutiny over campaign finances. His acceptance of $3 million from Indian gaming interests sparked controversy, so he said he'd donate the cash to a campaign aimed at defeating a ballot question on racial identification. Now, The Los Angeles Times reports, that move might be illegal.