Below are two birds...
Study them closely...
See if you can spot which of the two is the female.
It can be done!
Even by one with limited bird watching skills...

Bird Watcher
Bird Watcher Exam
Titanic's Non-Romantic Scene
see also Cats and Backpacks
Frogs Switch
Irish Exam
Math Puzzle
Spot The Clock
Spot The Hidden Cell Tower
Spot The K-Mart Shopper
Spot The Mistake
Spot The Man's Head
Spot The Thief
suDoku at suJoku