The angle of the illusion makes a big difference. Nearly horizontal like that is quite an odd rabbit head-posture so is biased towards duck. At a slight angle, e.g.: http://www.dgp.toronto.edu/~stam/suomi/stam/pics/duck_rabbit.gif I tend to see rabbit.
I'm ambidextrous and saw both at once?
The angle of the illusion makes a big difference. Nearly horizontal like that is quite an odd rabbit head-posture so is biased towards duck. At a slight angle, e.g.: http://www.dgp.toronto.edu/~stam/suomi/stam/pics/duck_rabbit.gif I tend to see rabbit.