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. Rain, sun, wind...insects, birds, flowers...meteorites, rocks...seasonal changes...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. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
September 2014
Salish Sea, Pacific Northwest
Someone who explores the woods more than I do took me out on a walk recently to see a nest she'd found with some bird detritus beneath. Neither one of us can figure out who built the nest. Perhaps you, Dear Reader, will have some thoughts from the clues we found and what you know about birds.
Important! I would never go traipsing around under a nest, especially a large one like this, at any time of year but now: the off-season. Starting in late winter birds begin preparations, and do not complete the breeding season until July or August when the juveniles have dispersed. On the off chance someone might, I'm being deliberately vague about the location of this nest. Another factor nature explorers should be aware of is who owns the land where they are walking, and to respect private property. Our walk on this occasion was on public land.
Here's the nest, approximately 50 feet up in a Grand Fir, secured to several branches at that level. The tree trunk is about 1.5' in diameter, so I'd say the nest is maybe 2 feet by 2.5 feet.
Clues beneath the clump of detritus...
(All photos by me. In Lightbox...click to enlarge)
Beneath the nest tree there were many Great Blue Heron feathers, mostly down feathers but a few larger. There were also signs of bird poop on the salal and moss around the tree. My companion reported seeing lots more bird poop and feathers the previous week, including a small eagle feather. However a heavy rain downpour since then had washed the understory pretty clean. A few wet and bedraggled heron feathers remained.
The tree is in a small patch of forest with a bay, ponds and open sea nearby. Here's a view of the forest from the edge of the water:
Several herons can almost always be seen standing motionless in the shallow water of the nearby bay so it's not surprising there would be roosting spots in these woods where they groom and survey the surrounding area in safety. Herons definitely perch in trees (like this one in my yard once) though they aren't usually so visible. Generally you hear them before seeing them, a noisy rustling of huge wings and a loud prehistoric croaking as they flap slowly off.
But bird experts (Cornell Ornithology, Birdweb) say Great Blue Herons usually nest communally, and that solitary nests are rare. The nearest heron rookery I know of is 30 miles away on another island. Perhaps this spot is a rare nesting site or perhaps it is a frequent roost, to account for the plentiful feathers below. Herons lay 2-6 eggs at a time, a faint light blue when fresh.
Besides the feathers, there's another clue. Eggshells. My companion had earlier found some mostly intact shells on the mossy forest floor near the nest tree. There were still some fragments when I went out to see, in three different locations. Here is a photo of one site:
These are the shells she found. Huge eggs!
So another question is who might have laid these eggs and are they related to the nest?
There aren't many birds that lay really big eggs where I live: Great Blue Herons, Canada Geese, Bald Eagles, and Wild Turkeys. Here's some information about these birds locally.
I've mentioned what I see of Herons already.
Geese? These woods are farther from the beach than geese usually nest, based on the goose nests I have seen. Straight line from the shells to the bay: quarter of a mile. Canada geese do not nest in trees but since I see several geese families in the bay every year they must nest in the area. Geese lay 5-8 eggs at a time. Here is a nest I saw in May:
and this is part of a group of three families I saw in June:
I also see - and hear - a pair (possibly pairs) of Bald Eagles and other single eagles regularly in this area, coming and going from these and other nearby woods, or perched on the beach. Their piercing calls are unmistakable. I have better eagle pics, but here is a photo of a pair of eagles feeding on the beach by the trees I showed above:
and this is a photo of an eagle's nest known to locals on the island. I snapped a pic of it today. Nobody there now but eagles typically lay two eggs. That Douglas fir is a little less than a foot and a half in diameter up at the nest level, so you can judge the nest size for yourself. This nest looks more organized and round than the mystery nest.
I have not seen Wild Turkeys, nor have I heard or read any reports of them in the area of these woods, though there are some wandering other parts of the island.
Egg size, from Cornell Ornithology. I imagine there are factors that cause some variability, putting individual eggs outside these ranges.
Canada Goose: 83 mm
Bald Eagle: 58-84 mm
Great Blue Heron: 61-76 mm
Wild Turkey: 49-69 mm
The eggshells my companion found measure 70 mm and 79 mm. The numbers say the eggs are too small for goose, but perhaps our island geese are smaller? There were the remains of at least 3-4 eggs, which seems too many for eagle, even though the egg sizes fit eagle better. The smaller egg could be heron, and possibly the larger. The eggshells are too big for turkey.
Or might these eggs/eggshells have been hauled in from elsewhere by predators and have nothing to do with the nest? Or could the shells be from more than this year (though that seems unlikely, given how fragile they are).
Regardless of the nest and eggshell mysteries, I found the discarded feathers on the forest floor delightful and beautiful, like these downy cast-offs I found sheltered from the rain. See the tiny pinkish one by my thumb? Great Blue herons have many more colors in their plumage than blue.
I'd be interested to hear your thoughts about this mystery nest and eggshells. Fresh eyes.
And of course the Bucket is open as always for your own observations of nature where you live. How is autumn coming in - what changes are emerging, what remains are you seeing from the busy summer season?
~
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