While observing some Red-Breasted Mergansers at Bolsa Chica Ecological Reserve I noticed several engaging in behavior I'd never seen before: skimming vigorously with head mostly down for several seconds. See one sequence photographed at right and below. It kept going a second or two past the last photo in the sequence.
Update: Experts tell me that this is usual behavior for this species, associated with feeding. Their diet is fish.

5:09:17 PM

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0.8 sec

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1.6 sec

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Stretching its wings 15 seconds after beginning of sequence