Nesting Eagles

Philadelphia has a third bald eagle nest within its borders.

Officials expect the Navy Yard eagles to return to their nest near the Delaware River, perhaps within days.

Another pair has built a five-foot nest in a remote area of Pennypack Park in the Northeast.

And over the last few weeks, birders have seen a pair of young adults taking sticks to a large oak tree on an island at the John Heinz National Wildlife Refuge at Tinicum.

There seems to be some doubt about the viability of the new Tinicum nest.

Eagles have been seen fishing all along the Delaware River - as well as at Tinicum - in recent years. But this is the first time the birds have nested at the refuge near the airport since its founding in 1972.

The Tinicum nest seems a bit tenuous. The birds are young adults, and have carried just about a dozen sticks out to the tree.

"It's a pretty shabby-looking nesting attempt," said Buchanan.

Whether the female actually lays eggs this winter - February is typical - and whether the eggs will hatch are questions that have prompted much speculation.

Apparently the Navy Yard nest failed in its first year but produced a successful fledge in its second year. So, even if this year's attempt at Tinicum fails, there is still hope for success in the future. That is, provided that a nest failure is not the result of harassment.

I find it interesting that bald eagles are carving out territories within cities. Urban areas present disadvantages for a large raptor such as a bald eagle – what habitat exists is likely to have heavy human traffic, and food sources have a higher risk of contamination from runoff and other sources. I wonder if this is a result of better territories being already taken, substantial improvement in existing urban habitats, or a bit of both. What do readers think?