Christine Elliott remains the favourite by a wide margin for first choice in the Progressive Conservative leadership race, a new poll suggests. But the race would tighten up in a second or third ballot.

Elliott, the MPP for Whitby-Oshawa, holds 29 per cent support among Progressive Conservative voters on the first ballot, but that drops to 19 per cent on a second ballot and 14 per cent on a third, says the latest Forum Research survey.

The outspoken Lisa MacLeod, MPP for Nepean-Carleton, would lead on a second ballot with 25 per cent support among PC supporters in a contest that culminates on May 9.

“With Doug Ford out of the race, that’s shaken some things loose,” Forum president Lorne Bozinoff said Monday.

The poll of 1,058 Ontarians over age 18 was conducted last Friday and Saturday. Forum says its margin of error is plus or minus three percentage points, 19 times out of 20.

Second and third choices could be crucial in the effort to replace the ousted Tim Hudak in the event that no candidate wins on the first ballot. That’s because voters cast ballots only once and must list their candidates in order of preference.

“Remember, Dalton McGuinty was no one’s first, second or third choice,” Bozinoff said, referring to the 1996 Liberal leadership contest that saw the future premier place fourth on the first ballot at a delegated convention held in Maple Leaf Gardens. McGuinty finally won on the fifth ballot.

Following MacLeod on a second ballot would be Elliott with 19 per cent, Nipissing MPP Vic Fedeli with 15 per cent, Barrie MP Patrick Brown with 11 per cent and Lambton-Kent-Middlesex MPP Monte McNaughton with 10 per cent, according to Forum. Twenty-one per cent of respondents picked none of the above or had no preference.

Bozinoff said MacLeod’s reputation for repeatedly taking Premier Kathleen Wynne’s Liberals — plagued by the gas plants and MaRS scandals — to task is helping her.

“She’s a good attack person, she’s done well on TV … she’s strongly carrying the fight against the Liberals.”

Given the poll’s margin of error, the numbers shift for a third ballot and get even tighter, with MacLeod slipping to 18 per cent and Brown — the only candidate in the race who doesn’t hold a seat at Queen’s Park — at 19 per cent.

Elliott and Fedeli follow at 14 per cent, and McNaughton at 13. Twenty-two per cent of respondents picked none of the above or had no preference.

Clarification- Dec. 23, 2014: This article omitted some information about the margin of error of the Forum Research Poll. While the margin of error was, as reported, plus or minus three percentage points, 19 times out of 20, the margin of error for the smaller subset of PC-leaning voters was plus or minus five percentage points on the second choice for leader and plus or minus six percentage points on the third choice .