Locals we met in Lake Louise recommended the Lake Bourgeau hike.  The combination of a cloudy day and some altitude gain made it pretty chilly, about 45F, but it was a great one for animals.   We saw ptarmigan, mountain goats, and some really pesky gold mantled ground squirrels.  They are adorable and people feed them then they get annoying as they climb on you and get into your stuff.  Still, they were cute.