The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the world around you. Snails, fish, insects, weather, meteorites, climate, birds and/or flowers. All are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located.
It's still a bit of a mystery about the large bird tracks I saw on the beach at Barlow Bay a couple of weeks ago. It may always be a mystery, since marks in the sand are ephemeral, erased by tides and wind, as these are now. Photos help, but there are so many variables that affect what's left, it's hard to interpret. Any insights from fellow nature lovers, more experienced than me, would be very welcome!
These tracks were fairly high up on the beach, near the high tide line, where the sand was dryer, so they were not as sharp as they would have been in damp soil. But the size caught my attention.
Each was at least 6 inches long, and in this bay there are only two birds that could make tracks that big, a Great Blue Heron (Ardea herodias
) and a Bald Eagle (Haliaeetus leucocephalus
). I've seen both birds in this bay.
The photos below were taken of them in the bay recently - though not at the site of the tracks. The beach is narrow, with a road just a few feet away, and birds don't linger when a person walks up (interestingly, they don't mind auto traffic, unless a car stops). The heron in this photo is fishing from a dock, sitting on his heels, toes hanging over the edge.
The eagle is on a small island just offshore (having a showdown with several otters who were hoping to climb up there).
I'd have assumed the tracks were left by a heron, since they they spend most of their time on the beaches standing patiently waiting for small fish or crabs to wander by in the shallow water before it. But the tracks looked unusual for a heron. Could they be an eagle's? Or was the dryish sand distorting the heron track?
I did a little investigating, looking up shapes of tracks in resources like this one
from Perdue University, which shows the eagle toe tracks thicker and discontinuous, a distinct claw at the end. The heron toes are thinner and often not spaced evenly in the track (2 close together). The eagle track is deeper in the sediment, which makes sense, since it weighs twice as much.
I also looked at some tracks that I knew were from each of these birds for certain.
Great Blue Herons are very often stationed on the next beach over, at MacKaye Harbor. Sometimes there are 2 or 3 of them a hundred yards or so apart along there, where I took this photo, with a boot print for scale. All the toes are narrow, variously splayed, and have pressed the sand down evenly along all the toes. Here's another set of tracks, in a bigger view, with various dog and gull tracks in the mix.
Eagle tracks were harder to come by since they are rarely on the beach. One time I did see and photograph them was a few years ago while walking out on Shi Shi beach, on the outer coast of Washington. Half a dozen adult and juvenile eagles swooped over a spot, landing, taking off, and perched in nearby trees. As I approached, this juvenile eagle ran a few steps and took off from the point of their attention, just behind a dune.
When I got close enough, I saw it was a harbor seal carcass (Phoca vitulina
) they were working on. It had been there for some time, but there was still a little to scavenge. Judging from the confusion of tracks, a lot of birds (and possibly mammals) had been at it, so it was hard to see distinct shapes. I put my boot next to one, for scale. There are also raven tracks - I saw one fly up from the carcass also. But in the mass of marks on the sand, you can see the large eagle tracks, with the wide splayed toes, hooked at the ends.
Looking back at the tracks on Barlow Bay, the deeper thick prints suggest eagle to me. But there are also lighter evenly pressed tracks in the same spot. Could both birds have walked around right here? Was it at about the same time? Or are these several sets of heron tracks that look different because of the nature of the sand or what they were doing? I don't know. Any thoughts? Any trackers out there?
Unseen bird mystery. It's hard enough identifying them when I can see them! What are you seeing, or hearing or smelling today in your part of the world? All observations are welcome in the Bucket.