robin

Robin is short for robin redbreast, and traces back to the Middle English name Robynett, itself a diminutive of the name Robyn — the medieval form of Robin.

What began as a nickname for a boy named Robin became attached to the bird through the pet name 'robin redbreast,' and eventually the bird kept just the first part of that name for itself.

The facts point to Robynett and Robyn as the direct ancestors, showing this bird's name is really just a shortened human name in disguise.