By Robin Culverwell

PHILADELPHIA (CBS) – Bird-watchers keeping tabs on the nest of Red-tailed Hawks at the Franklin Institute have reason to rejoice: The mother hawk has allowed an unattached male to bring food to her babies.

It’s not unheard of, but it’s certainly rare that a mother would let a stranger near her brood:

“It is a surprise beyond belief,” says the Franklin Institute’s president, Dennis Wint, who first noticed the male flying around the red-tailed hawk’s nest on Monday.

The three fledglings are healthy and growing, and the “step-dad” is fitting right in after swooping past:

“[He] sits right there with the female then goes into hunting mode, also bringing back food.”

Wint says so far, so good, but this is uncharted territory for hawk watchers. As for the little ones—they’re peering over the edge of the nest, indicating it won’t be long before they want out.