The Daily Bucket is a nature refuge.
We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
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December 21, 2019
Salish Sea, Pacific Northwest
As you all heard, we had a deluge of rain from last Wednesday night right into solstice day (Saturday). The relentless downpour finally started slowing down by solstice afternoon, and I was happy to go out for my walkies even as that short day waned. Turns out others were out and about too. Most splendidly for me was a troupe of Black Oystercatchers foraging in the rocks.
Oystercatchers have a bright orange beak, but their black plumage blends into the rocky background so well it’s hard to see them unless they’re talking, or close up.
Like other shorebirds, oystercatchers are constantly busy when feeding, but they have an extra reason not to waste any time, especially in winter. These birds only feed in the marine intertidal — that means they can only fuel up during the short time when the tide is low enough to expose the invertebrates. Winter is a double whammy for them: not only are there few daylight hours to hunt, but the highest tides occur in the daytime at this season. Above 6 feet (7 at most) there isn’t much scope for foraging. When I was out there watching them at 3:30pm, the tide had gone down to 4 feet but they had less than an hour left to feed.
They were scouring the rocks, mostly for limpets, which they pry off the sides and bottoms of rocks, surprising them before the little gastropods can latch on securely. Oystercatchers have malleable padded feet that provide great traction on any surface.
I counted nine birds total although it was hard to be sure since they were in constant motion. Every few minutes they’d all take off and regroup at another spot on the beach. One would call out, and off they went.
Only in winter do oystercatchers flock together like this. In breeding season they split up. This particular group had two adults and seven youngsters who hatched last summer — how to tell? immature birds have neither a fully orange beak nor an orange eye ring. The moments when they landed, before resuming foraging, were the only times I could see all their beaks at once. Sort of.
According to Birds of North America, the youngsters aren’t yet up to speed on hunting.
By midwinter, foraging efficiency of chicks is slightly below that of adults (Groves 1982, Falxa 1992). Immature birds take >3 yr to develop complete repertoire of efficient foraging skills (Falxa 1992).
birdsna.org/...
Take a look at this short clip and see what you think.
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When dusk comes, they will all fly off to their nightly roost on an outer rock or island. There they wait the 16 hours until it’s light enough to head out to another shoreline in the morning. They will have a short window to forage until the tide covers the rocks again. Then they’ll wait for it to ebb.
No wonder they are so busy whenever I see them. A little rainfall does not signify for oystercatchers in winter.
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Overcast and cool in the PacificNorthwest islands today.
What’s up in nature in your area today?
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