There were no seat changes in Monday's federal byelections, but the governing Liberals took a hit in all five of the contested ridings — marking their worst byelection performances so far under Justin Trudeau.

The Conservatives saw gains in three of the five ridings while the New Democrats took hits of their own in all but one, leaving the Conservatives as the winners of the night.

The Liberals held on to the three ridings they were defending (Markham–Thornhill, Ottawa–Vanier and Saint-Laurent) while the Conservatives retained their two seats of Calgary Midnapore and Calgary Heritage, the latter being the old seat of former prime minister Stephen Harper.

But across the five ridings, the Liberals' vote share dropped by an average of 4.7 points. That was a steeper loss than the NDP's average 2.2-point decline. The Conservatives gained an average of 4.2 points compared to their support in the 2015 federal election.

This is a reversal of the trends exhibited between the 2011 and 2015 votes, when the Liberals made gains in 13 of 15 byelections and the Conservatives suffered losses in all of them.

Granted, byelections can be largely driven by local issues. But being on the wrong side of the trend line does not bode well for future performance.

Liberals drop across the board

Turnout was low on Monday, ranging from 27.5 per cent in Markham–Thornhill to 34.1 per cent in Ottawa–Vanier. Accordingly, the big parties lost votes in every riding — and the Liberals lost vote share across the board.

Though the most significant decline for the Liberals occurred in Ottawa–Vanier, the result for Mona Fortier (51.2 per cent of the vote, down 6.4 points) was better than the late Mauril Bélanger's scores between 2004 and 2011, when the Liberals were either in opposition or reduced to a minority government.

Support for Prime Minister Justin Trudeau's Liberals fell from their 2015 election results in all five byelections Monday, including Calgary Midnapore, where Trudeau campaigned for candidate Haley Brown, right. (Jeff McIntosh/Canadian Press)

The nomination controversies in Markham–Thornhill and Saint-Laurent did not seem to have a disproportionate impact on Liberal fortunes, as the decreases suffered there by Mary Ng (down 4.4 points to 51.3 per cent) and Emmanuella Lambropoulos (down 2.5 points to 59.1 per cent) were not notably different than those in the other three ridings.

The Liberals were unable to maintain the gains made in Calgary in 2015 (when they won their first seats there since 1968), capturing 21.7 per cent of the vote in Calgary Heritage (down 4.3 points) and just 17 per cent in Calgary Midnapore (down 5.7 points). Nevertheless, with the exception of 2015, those were the party's best results in the ridings since 1980 and 1997, respectively.

Conservative gains in Calgary, Markham

With 71.5 per cent support for Bob Benzen in Calgary Heritage, up 7.7 points from 2015, and 77.2 per cent for Stephanie Kusie (+10.5) in Calgary Midnapore, the Conservatives made a renewed show of strength in two traditional strongholds. Kusie's score in Calgary Midnapore was the Conservatives' best in the riding since the merger of the Progressive Conservatives and Canadian Alliance in 2003.

Conservative candidate Stephanie Kusie celebrates with her husband James and son Edward after winning Calgary-Midnapore. (Todd Korol/Canadian Press)

The Conservatives also put up good numbers in Markham–Thornhill, the kind of GTA riding the Conservatives will need to win in the future to form a majority government. The party captured 39 per cent of the vote, up 6.7 points and their best performance since 1997 — when the Liberals last lost the riding.

But the Conservatives put up worse results in two francophone ridings, Ottawa–Vanier and Saint-Laurent. The party held its 19.5 per cent vote share in the Montreal seat. In Ottawa–Vanier, the Conservatives were down 3.7 points, their worst performance there since 1968.

It is possible the Conservative leadership race has helped boost the party elsewhere, but the lack of French-language skills among the field of 14 candidates for the top job (including one of the front-runners, Kevin O'Leary) may not be doing the party favours in ridings with large francophone populations.

NDP gains in Ottawa–Vanier, loses elsewhere

The New Democrats saw their vote drop most significantly in ridings that were primarily head-to-head contests between the Liberals and the Conservatives — down 4.4 points in Calgary Heritage, 5.2 points in Calgary Midnapore and 7.2 points in Markham–Thornhill.

Their numbers in these three ridings were their worst since before Jack Layton took over the party in 2003.

The loss of 3.7 points in Saint-Laurent is not a good sign for the New Democrats in Quebec, where the party needs to regain some lustre.

But the results in Ottawa–Vanier were far more positive for the NDP. The New Democrats gained 9.4 points, reaching 28.7 per cent and nearly matching their all-time best performance in the riding in 2011.

Liberal candidate Mona Fortier, centre, won the Ottawa-Vanier byelection. (Justin Tang/Canadian Press)

Mid-term report card

The Greens saw little change in their numbers with the exception of a gain of 5.6 points in Saint-Laurent, where their deputy leader, Daniel Green, was a candidate. The Bloc Québécois, in its first electoral test under new leader Martine Ouellet, did little better in Saint-Laurent than the party did in 2015, but also no worse.

So the results of the byelections have something to please each of the opposition parties, with the Conservatives having the most to smile about in addition to their two wins.

On the government's side, their three comfortable victories might be little to worry about just yet. But if these byelections acted as a mid-term report card for the Liberals, they might want to return to their studies or risk failing the next test.