I'm with Kevin (Greenwald) on this subject. Although having achieved over 250,000 miles of riding in 38 years, mostly in Wisconsin, I have been fortunate to never have to take evasive action on my bikes. Other than slowing down at night, having extra lights on my bike, watching for where-ever the deer may be (everywhere), and having good/practiced braking abilities, I have been lucky to not have had a bike/deer encounter.
Can't say the same for cars though, as I have had four deer hits in cars and many more than that in close calls with deer. The latest, early Sept 09, 10am on a bright sunny Friday morning, a good sized buck broadsided my 2007 Ford 500 from my left hand blind side. It simply ran right into the car!! Kamikazee style, or perhaps Taliban style? Also, two of the hits, I swerved to go behind the deer, and the damn thing turned back around and got nailed! So I can't say that swerving is an effective evasive manuever.
I think the broadside hit has something to do with the way deer see, being that they have an eye more or less on each side of their head. When running, or fleeing a predator, it seems they lack a sense of depth perception. Because why would an animal run directly into something large and moving like a car? I know other car drivers that have been broadsided by deer, at the midpoint of their car. Even heard of car crashing through the side windows of the car.
Now, as to this comment: "A J Foyt would probably say "aim for the accident, because by the time you get there it will be somewhere else."" I tend to agree. If you feel a deer hit is imminent, brake HARD to reduce the energy of the impact, and aim for the deer's butt. Hopefully it won't be there when you get there!
Deer hits was discussed at our recent club meeting, as deer strikes have been very high this past month in Wisconsin. In fact, Waupaca county records 10 deer strikes per DAY, 300 a month in one county! One club member brought up the ol deer whistles myth again. I simply cannot put any faith in such a whimsical and unproven gimmick. Especially since the installation instructions say the whistles have to be voer 2.5' apart to be effective. Rely on your smarts and riding abilites. And PRACTICE your riding skills!