Now that the Conservatives have dropped to third, are the Liberals about to swap position with the New Democrats at the top of the polls?

The Liberals have been gaining steadily in the CBC Poll Tracker since Sept. 1 on the strength of several polls showing higher levels of voter support. The party has picked up 3.8 points since then, and now stands at 31.5 per cent in the polling average.

That puts Justin Trudeau's party just a tenth of a percentage point behind the New Democrats, who cling to the lead with 31.6 per cent support. The Conservatives remain in third with 28 per cent, while the Greens stand at 4.7 per cent. In Quebec, the Bloc Québécois continues to struggle with 14.5 per cent support.

With these levels of support, the New Democrats are projected to win between 107 and 134 seats, the Liberals between 94 and 133 seats, and the Conservatives between 87 and 122 seats. But in the average projection, the Liberals are narrowly in front with 119 seats to 113 for the NDP and 105 for the Conservatives. This marks the first time in 2015 that the Liberals are leading in the average seat projection.

But is this new change in the order of the parties for real?

The last two three-day rolling polls from Nanos Research conducted for the Globe and Mail and CTV have both put the Liberals in first place, with a narrow edge of 1.3 to 1.5 points over the New Democrats. The newest set of numbers put the Liberals at 32.1 per cent, the NDP at 30.6 per cent, and the Conservatives at 28.6 per cent support. The gap between the NDP and Liberals is within the margin of error, so the new Liberal lead could be easily reversed once the next day of sampling is added to the rolling poll.

The two other most recent polls from Ipsos Reid and Léger suggest the Liberals have 30 per cent support, with Ipsos still putting the Liberals in second place by a margin of four points, and Léger by a margin of just one.

Ipsos's poll was the only other one conducted within the last week of the campaign, and a probabilistic sample of decided voters in a survey of its size would carry a margin of error of plus or minus 3.5 points — more than enough to erase the four-point gap between the Liberals and NDP (or, to be fair, extend it even further).

Ontario behind the moving numbers

If there is one part of the country that seems to be behind the Liberals' improving national numbers, it is Ontario. And this is not just from the Nanos polls. Though the last three rolling polls (which overlap in terms of the days they were in the field) have put the Liberals between 38 and 43 per cent in the province, the most recent Ipsos and Léger surveys have the party at 36 or 37 per cent. This marks a significant divergence from the close three-way race that held in the province for much of August.

One point of contention between the latest set of polls, though, concerns the position of the NDP in Ontario. Ipsos and Léger have the party in a competitive position, whereas Nanos has the NDP down to just 18 or 20 per cent in the province. This, more than anything else, is enough to drive the New Democrats behind the Liberals in the national count.

So, we need to see what the next few days of polling will show to determine what is going on at the top of the polling table. Keep an eye on Ontario.

CBC's Poll Tracker aggregates all publicly released polls, weighing them by sample size, date and the polling firm's accuracy record. Upper and lower ranges are based on how polls have performed in other recent elections. The seat projection model makes individual projections for all ridings in the country, based on regional shifts in support since the 2011 election and taking into account other factors such as incumbency. The projections are subject to the margins of error of the opinion polls included in the model, as well as the unpredictable nature of politics at the riding level. The polls included in the model vary in size, date and method, and have not been individually verified by the CBC. You can read the full methodology here.

The questions asked in the polls mentioned in this article were as follows:

Nanos: "If a federal election were held today, could you please rank your top two current local voting preferences?"