What happens to a big dead animal on the beach in the Salish Sea? Earlier this summer I had a chance to watch a bit of the recycling of one. I wasn't sure if peeps would be comfortable seeing pictures of a carcass, but hey it's nature, with two of my favorite creatures, Bald Eagles and Turkey Vultures, doing what they do, so here's the story of what I observed in these inland waters of the Pacific Northwest.
We were taking a walk after dinner down to the beach, still broad daylight even at 8 pm so near midsummer's day. Heard a commotion in the trees above, looked up and saw this juvenile eagle perched 20 feet above where it had just landed.
I'd been seeing this eagle family recently in the area, two parents and two recently fledged eaglets, flying from one beach to another. Here's the dad of the family.
Tonight there was a lot of activity at the beach we were headed to, usually very quiet and empty. All four eagles were alternately flying, perching and landing on the far end of the beach.
The eaglets were getting practice coming in for landings on the fir branches, sometimes knocking the other off. Quite a bit of crashing around in the trees. The eaglets and the two adults were taking turns working something on the beach, which was about to get covered by the incoming tide.
When it began to get dark, the eagles departed, and I walked down to see what it was. The time stamp on this picture is 9:06 pm, and the sunset 9:08. The carcass looked fresh and it had no odor. The size of the spine suggested a large animal, but just a portion of it (can you see the crab working on the soft parts? just its legs in this pic).
As often as not our eagles are scavengers. Yes, they are powerful predators, swooping down and snatching up fish, ducks, gulls, and such (and around here, domestic chickens and our over-abundant introduced rabbits). But they take full advantage of carrion. I see them frequently feeding on roadkill deer, and like this, on the beach.
Curious, I decided to return the next day to see what became of the carcass. Come with me below the fold.
The next day was pouring rain, not heavily but steadily, typical for the Pacific Northwest. I watched at the beach for about an hour in the gray misty silence. One eagle glided in, perched on a rock for a while, then waded into shallow water. It tore at what it was standing on for a few minutes and then flew a short distance across the bay to a small island. Gray still air over a calm gray sea, sounds muted by the soft rain. A Harbor Seal swam into shallow water along the beach, circled the small island, and disappeared out to sea. The eagle stood motionless in the rain for at least half an hour. Outlasted me...wet and cold, having nowhere near the quiet patience of an eagle, I went home.
Solstice day was bright and sunny. Our weather is changeable like that. Besides the songbirds' busy activity in the trees and field above the beach, several Turkey Vultures circled. The vultures are common in the summer, cruising silently by overhead. This year they arrived from their migration unusually early, in February.
Vultures are the master soarers in our sky, using thermals to gain altitude, rarely flapping, changing direction with a slight tip of their wide v-shaped wingspread. These were eyeing the far end of the beach.
I'd seen one soar past the evening the eagle family feasted, but it didn't land.
Today two settled there and spent some time on the rocks, one spreading its wings, warming and drying them, much like cormorants do, in the bright morning sun.
Getting a little closer I could see the other one was eating. They were higher up on the beach than where I'd seen the eagles feeding earlier, but I knew there had been several very high and low tides since then, typical for this time of year, almost certainly pieces of carcass would get washed around.
Like the eagle, it used its weight on the carcass to tear against. Vultures' beaks aren't as big or strong as those of eagles so they usually go for soft parts of carrion or wait until those have been exposed by other animals. The Turkey Vulture (Cathartes aura, or "purifying wind') does not kill animals, nor does it harass a dying one, in spite of its reputation. It can wait patiently for days for a sick or injured one to die though.
After this vulture took wing I got a closer look at what it had been standing on, pulling pieces from. The gray and black pattern of fur told me this had almost certainly once been a harbor seal (Phoca vitulina
Those 5-foot marine mammals are common residents of the Salish Sea, fishing and hauling-out offshore. Their primary predators are the 'transient' orcas, so-called because they range farther and less predictably than our 'resident' orcas (a misleading term since they leave the Salish Sea all winter). Even though all the orcas are the same species, they are distinctly different populations, and do not interbreed. Genetic analysis indicates this has been so for tens of thousands of years. They even have their own languages. Whereas the residents eat fish, and travel in large multi-family groups calling frequently to each other as they hunt and socialize, the transients live in small groups, and hunt large mammals, stalking them silently.
These are Harbor Seals soaking up some sun on the rocks outside this bay. I took these photos while kayaking, on another occasion.
The pieces on the beach might have washed up after orcas had their fill out in the bay. All that was left in this piece was the skin and fur. The skeleton piece further down toward the water was gone entirely by now.
High tide brings in the small aquatic scavengers, like crabs, fish, various worms and even smaller creatures. Low tide is wide open for terrestrial ones, and even leftover portions of a seal provide lots of food for them. After these few days, not much was left useful to eagles or vultures.
I went away on a trip after this last day. When I walked the beach on my return, all signs of carcass were gone. A clean beach: completely recycled nutrients. The tides and waves and currents move material around, but it's the biological creatures, from huge eagles to microscopic bacteria, that really do the clean up.
For more about these animals: