* Canadian dollar falls below 80 U.S. cents
* Bonds mixed, long end unwinds some of Monday's gains
* No economic releases to drive direction
By Ka Yan Ng
TORONTO, Dec 2 (Reuters) - The Canadian dollar fell for a fifth straight day against the U.S. dollar on Tuesday on retreating oil prices and political uncertainty in Ottawa.
Bond prices were mixed in low volume, as the short end eked out gains as the Toronto Stock Exchange fell.
The Canadian dollar finished the North American session at C$1.2510 to the U.S. dollar, or 79.94 U.S. cents, down from C$1.2451, or 80.31 U.S. cents, at Monday's close.
It was the first time the Canadian dollar closed under 80 U.S. cents in a little over a week and further weakness may emerge as themes of falling commodity prices and political uncertainty play out in the next few sessions.
"I think to a certain extent the Canadian dollar was playing a little bit of catch-up to yesterday in terms of what happened to equities and commodities," said George Davis, chief technical analyst at RBC Capital Markets.
"Today again we got some further weakness in crude oil. The political backdrop is going to be a bit of an uncertainty until at least until next Monday."
A political crisis -- which tends to weigh on currencies -- has gripped Canada in recent days as the minority Conservative government may seek the temporary suspension of Parliament to stop opposition parties from voting it out and taking power. [ID:nN02696]
The government is expected to face one or two confidence votes shortly after 6:30 p.m. (2330 GMT) next Monday, as one of several possible scenarios on how events could play out. [ID:nN02438616]
Slumping oil prices also weighed as U.S. crude CLc1 fell nearly 5 percent to below $47 a barrel, extending its slide to more than $100 from its record high in July. [ID:nN02282286] Canada is a major oil producer and its currency is often influenced by moves in the oil price.
The Reserve Bank of Australia cut interest rates by a bold 100 basis points, and all eyes will now turn to other central banks to see how much they'll move to stimulate their economies and stave off recession.
The Bank of Canada will announce any changes to its overnight rate next week, while the Bank of England and the European Central Bank are on tap for Thursday.
Canadian bond prices finished mixed under muted trading volumes, partially responding to rebounding stock markets and giving up recent gains.
"A little bit of a give-back today isn't totally unexpected. The other thing today is that (U.S.) stock markets are closing in the black," said Sheldon Dong, a fixed income analyst at TD Waterhouse Private Investment.
The political uncertainty in Canada is low on the list of priorities for bond market watchers, Dong said. Instead, central bank watching, equity market movements, and economic data are a stronger focus right now.
In addition to expected interest rate cuts from major central banks this week, market players will also see employment data from Canada and the United States.
The two-year bond rose 3 Canadian cents to C$102.29 to yield 1.578 percent. The 10-year bond was unchanged at C$108.95 to yield 3.151 percent.
The yield spread between the two-year and 10-year bond was 158 basis points, down from 171 at the previous close.
The 30-year bond lost 10 Canadian cents to C$121.40 to yield 3.151 percent. In the United States, the 30-year treasury yielded 3.177 percent. (Reporting by Ka Yan Ng; editing by Rob Wilson)