You have a certain average to maintain every year to remain in honours, yes. I believe that is a 6.0 for Soc Sci/Humanities programs.
If you do not/are not able to enroll in an honours program by the completion of your third year, you will not be able to graduate with an honours degree in Poli Sci (Honours Bachelor of Arts), you will graduate with a Bachelor of Arts.
You can also check out the under grad calender section on Poli Sci in lieu of seeing your faculty office before they open:
http://registrar.mcmaster.ca /CALEN...09/pg1665.html
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McMaster Combined Honours Cultural Studies & Critical Theory and Anthropology: 2008
McMaster Honours English with a minor in Indigenous Studies: 2010
Carleton University Masters of Arts in Canadian Studies: 2012 (expected)
We are people of this generation, bred in at least modest comfort, housed in universities, looking uncomfortably into the world we inherit. -- Port Huron Statement