The Toronto Stock Exchange's TSX falls 0.20 percent to 16,800.29.
Leading the index were West Fraser Timber Co Ltd <WFT.TO>, up 5.4 percent, Bombardier Inc <BBDb.TO>, up 2.7 percent, and SNC-Lavalin Group Inc <SNC.TO>, higher by 2.6 percent.
Lagging shares were Ensign Energy Services Inc <ESI.TO>, down 10.2 percent, Birchcliff Energy Ltd <BIR.TO>, down 6.2 percent, and Precision Drilling Corp <PD.TO>, lower by 4.7 percent.
On the TSX 84 issues rose and 150 fell as a 0.6-to-1 ratio favored decliners. There were 8 new highs and 1 new low, with total volume of 230.8 million shares.
The most heavily traded shares by volume were Encana Corp <ECA.TO>, Kinross Gold Corp <K.TO> and Crescent Point Energy Corp <CPG.TO>.
The TSX's energy group <.SPTTEN> fell 2.17 points, or 1.5 percent, while the financials sector <.SPTTFS> climbed 0.61 points, or 0.2 percent.
West Texas Intermediate crude futures <CLc1> fell 2.11 percent, or $1.25, to $58.09 a barrel. Brent crude <LCOc1> fell 1.63 percent, or $1.05, to $63.5 [O/R]
The TSX is up 17.3 percent for the year.