A late afternoon light-knock at the door. Daisy with a big smile. “Two eagles are on a rock eating something! They are on a rock past Battery Steele marsh so you will need your bike.” Daisy wants to share this unusual sighting with someone, not just alone. Her cell phone had no reception to call home, so I was next in line to be included, and what a treat it is.
On a large rock, off the shoreline, is a Bald Eagle pair with their evening meal – an unfortunate bird with black feathers. We see a black wing – perhaps larger than a crow. A cormorant? The bird looks smaller – a Black Scoter? An orange color flashes from the blackness of feathers – the orange knob on the male Black Scoter’s forehead? The smaller (on the left) of the two eagles stands back as the larger one feasts on its prize.
A few more observers arrive – one couple with large telephoto lens – capturing the scene – up close and vivid. Sharing the view through their lenses.
Finally, the smaller eagle grabs a portion of the food, dragging it across the rock, away from the larger eagle.
A sudden tangle for the morsel follows. Their beaks are huge, as are the talons. The larger eagle lunges toward the stolen morsel, grabbing it with one talon and its beak, and taking it away - leaving the ‘picked’ over piece for the smaller eagle.
Finally the larger eagle leaves flying over Daisy on her bike – going to get cell reception to call home again. The eagle then flies over Battery Steele marsh – to Great Diamond Island?
The smaller eagle retrieves what is left of the stolen morsel, leaving 6 minutes later following the same flight path as its mate.
The ‘picked’ over morsel is left on the rock.
Many questions arise:
Is it the same pair that has been seen in previous years with a nest on Great Diamond Island, or interlopers that are migrating?
Pairs usually mate for life returning to the same nest each year from February to March (1, 2). Perhaps this is the same pair that has nested previously on Great Diamond Island’s east shore - in a large pine tree. Adults generally stay in Maine during winter. Sub-adults usually migrate south.
Where will they fly after feeding?
They flew over Battery Steele marsh – perhaps to Great Diamond Island?
Who is bigger, the male or female?
The female is larger at about 14 pounds with wingspan up to 8 feet; the male is smaller at 7-10 pounds with a wingspan of 6.5 feet (3).
Were they hunting together?
Did anyone see the hunt?
How did the eagle catch a crow, a scoter or a cormorant?
On the ocean surface (cormorant or scoter)?
In flight (crow, cormorant or scoter)?
Sitting on a rock (crow or cormorant)?
Ocean surface: As Jamie pointed out – cormorants are slow to lift from the water’s surface and are vulnerable to an eagle attack. And, a cormorant would be a heavy load for a Bald Eagle to carry. Black Scoters are migrating north and one may have been exhausted, separated from its flock, sleeping on the water - also vulnerable. We all know that eagles catch fish from the ocean’s surface, and that they are good at it. How efficient are they at catching water birds?
In flight: If it is a crow, perhaps it was caught in flight. They frequently mob eagles, sometimes very close – vulnerable to the talons. A cormorant or scoter will have nothing to do with mobbing an eagle in flight.
Sitting on a rock – a sneak attack? Birds have such great eyesight it is unlikely a crow or cormorant would miss a large mass of feathers flying toward them. Black Scoters do not sit on rocky shores, unless sick.
Whatever the events were that led to the eagles’ successful dinner we know that they have incredible eyesight and probably sighted their prey far ahead of when the victim took note. Their retina is densely layered with cones – far more than our retinas. More cones - higher visual acuity. Another feature of their eyes gives them extra magnification in the center of their vision similar to a telephoto lens view. (3)
No wonder birds go into a flurry when an eagle, or two, appear. Have you seen the gulls whirl up into the sky over Ram Island when an eagle approaches? Looks like an insect swarm. We think of Bald Eagles eating primarily fish, not our favorite birds. But they do.
1. Ackerman, J. 2020. The Bird Way. A new look at how birds talk, work, play, parent, and think. Penguin Press. NY. Page 94.
2. Vickery, P.D. 2020. Birds of Maine. Princeton Press. Pages 335-338.
3. Pezzenti, J. 1999. The American Eagle. Viking Studio.
By: Patty Wainright and Daisy Braun
Reviewers: Michael, Sam, Marty and Jamie