I am not sure I agree with you on this.
I think it is important to note that the Conservative growth has come directly from the Liberals. If what you suggest is true, we would see the Conservatives number holding steady while the NDP and Bloc numbers grow.
Currently, as with most of the election the Bloc and NDP have held steady.
I do agree that what you suggest may be true for individual ridings but not on the nation as whole.
Here is the latest Globe and Mail/CTV poll:
http://www.theglobeandmail.com/speci...2006/poll.html
Conservatives: 37%
Liberals: 29%
NDP: 17%
Bloc: 13%