No, this Killdeer is not waving hello or doing bird yoga--it is performing a species-saving technique called "the broken wing display". When a perceived predator gets close to a parent's nest or young, it scurries off, leading the predator away from a potential meal. By feigning injury, the parent deceives the predator into thinking it is in fact the easy target, thus saving its young from attack. Sometimes both parents dart away from their booty in different directions, which can truly befuddle a predator (or a photographer).
With a baby this cute, who wouldn't risk his or her own life?