January 12, 2026
Salish Sea, Pacific Northwest
A week ago we were still in the grip of back to back storms bringing wet and windy weather to the Pacific Northwest. Such days reduce what little light we have at this season to a dim grey sky. This combination of factors may have accounted for some unusual behavior I saw between several Black oystercatchers on a local beach.
Oystercatchers are very territorial and will vigorously drive away intruders from their domain. Two of my local bays are each claimed year-round by a pair of these large black shorebirds, who form longterm bonds. You can tell when another oystercatcher has entered their nesting/foraging territory by the piercing shrieks made by the resident pair. That call and posture is called the “piping display”.
From Birds of the World:
Piping is most common communicative display given by breeding pairs. It is used as greeting between mates or as territorial display toward intruders. Many aggressive displays are used to defend territory or repel intruders from feeding areas. Aggressors stare (often with contour feathers erected), Pipe, rush toward intruder with bill forward, or rarely, may jab or grasp another bird with bill or strike with wings. Extended aerial pursuits of intruders by territorial birds are common, often accompanied by Contact Calls and Piping. Pursuits end when intruder is driven out of territory.
It is common to see and hear these aggressive territorial behaviors around here. That’s why was surprising to see the resident pair at one bay demonstrating only semi-territorial behavior the other day, uncharacteristic for them.
It was late afternoon on that blustery day, with spitting rain and gusty wind under a dark grey sky. At first I saw three oystercatchers just standing on the rock. Sometimes in winter small flocks of oystercatchers form which fly from one shoreline to another to forage. Those are mixed adults and immatures (identifiable by their lack of orange eyering and beak tip). But all three of these birds were adults.
This erratic makes a handy lookout spot for birds (and eating table for otters)
Then two of the birds started up a Piping display, directing their aggression at the third. Ordinarily, what usually happens is the odd bird out flies away and things quiet down, but that’s not what happened. The interloper stood its ground, kind of.
It has retreated but choosing not to fly away
This 1:20 video shows what I saw (edited down from about 10 minutes):
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Note how the intruder left the prime real estate on the flat top of the rock, perching precariously and clearly uncomfortably on the side. But only for a while. When it rejoined the pair on the top, they chased it down to the beach.
The tide was moderately low which is unusual to have in daylight hours in winter. Prime foraging conditions for these shorebirds. On this cobbly/bouldery beach, their primary food source is limpets, and all three began earnestly hunting down those small gastropods. Had they reached an understanding that food was more important than territoriality? It seemed like the resident pair had mixed feelings.
The 1:31 video has a few clips of the three on the beach.
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The interloper refused to fly off. It didn’t even demonstrate submissive behavior beyond avoidance at times. The resident pair tried to discourage its presence but didn’t seem willing to get into a fight over the intrusion.
Resident pair, on left. Lone oystercatcher aware of them but not submissive, and certainly not leaving the area. It hunted steadily while the resident pair seemed distracted.
Perhaps the marginal weather and feeding conditions tipped the balance for all three birds — the usual rules aren’t hard and fast when survival is at stake? All three were still foraging at this end of the beach when I left.
A wet, windy, dark day on the beach….but a fairly low tide! Lots of limpets for oystercatchers.
🐦⬛
There’s a mega-ridge of high pressure over the PNW currently. Sunny cold weather and calm winds forecast for the rest of the week.
What’s up in nature in your neighborhood today?
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