It’s certainly understandable if you mistake this for a bird with a broken wing. This superb acting has been fooling would-be predators for millennia, and humans are no exception. But there’s no need to rush to call a wildlife rehabilitator. Chances are, this bird is actually just fine.
This is a mother killdeer. Killdeers live naturally through almost all of North and Central America and are a common sight through much of their range (though that may not be true for much longer, since their population is rapidly declining due to outdoor cats and habitat destruction).
When a mother killdeer sees a human or other animal near her babies— which are tiny chicks that live on the ground, rather than in trees— the mother pretends her wing is broken. This puts her in a very vulnerable position, but it often helps to lure the predator away from the chicks. It’s a very convincing display!
If you see a bird like this and it appears to be struggling on the ground with a broken wing, especially if it is making loud, sharp vocalizations, simply watch from a distance to see if she eventually gives up the act and flies. Do not approach or chase her, as this will often cause her to charge at you, which can break her neck and cause you a mild injury. Also, please avoid looking for her babies. You’re already near them, but actually finding them will distress their frightened mother even more.
There’s no need to intervene if you see a dedicated mommy doing this display. But it’s a great opportunity to admire the incredible lengths that a mother will go to, to protect her young.