By Molly Daly
PHILADELPHIA (CBS) -- The bald eagles at John Heinz National Wildlife Refuge in Philadelphia are spending a lot of time on the nest -- waiting for new life to emerge.
The eagles have a bun in the oven -- well, actually, at least one egg in the nest. Heinz Refuge manager Gary Stolz says this is the fourth year in a row the birds have bred there.
"They've been on the nest since early February, and we expect baby eagles to be hatching out around mid-March," Stolz explains.
Although it may seem early for birds to be nesting, Stolz says that's not the case for eagles.
"This is the exact right time of year. They are early birds, but they don't get the worm -- they go for fish."
Of which there are plenty, thanks to the refuge's large impoundment, which is teeming with carp and catfish.
As for the division of labor, these birds are remarkably...egalitarian.
"They do take turns -- they'll both be on there. Generally, one will be on the nest at all times, but they hunker down so low, it's sometimes hard to see," Stolz explains.
Stolz also says the mere fact that bald eagles are nesting is remarkable.
"This is the fourth year for us, and then there was one year prior to it, there was a nest at the Navy Yard. But prior to that, Bald Eagles were absent from Philadelphia, from nesting here, for over 200 years."
The refuge manager says it's testament to the effectiveness of the Endangered Species Act.
"What a remarkable change in our environment. It's just a perfect story of recovery. Perfect timing, too, because this is the 40-year anniversary of the Endangered Species Act. It was signed into law in 1973."
To see photos of the Heinz Refuge Bald Eagles, visit the Friends of Heinz Refuge Facebook page: https://www.facebook.com/HeinzRefuge?fref=ts
for more features.