Last Thursday my husband Jim and I were among those who were inspired by
Scott Ramos' Whidbey Island report from last Saturday to venture up to
Deception Pass to look for the spectacle of large numbers of Red-throated
Loons feeding near Deception Pass bridge.

In the past I had heard that large concentrations of Red-throated Loons
were sometimes to be found at Deception Pass but I'd never known what
triggered these concentrations.

Guessing that currents have something to do with this timing, before we
left home, I checked the current tables for Deception Pass for the previous
Saturday (the day of Scott's report) and realized that they saw the loons
on a major ebb. I checked the ebb for Thursday and saw that the max would
be around 3:34 pm so we timed our visit with that time in mind.

Here's a link to the currents for the day of our visit.
http://www.dairiki.org/tides/daily.php/dec/2017-12-14

We arrived at West Beach around 3:20 pm, parked and walked north to the
edge of the water where we could see the waterway, all the way to the
bridge. The influx of large numbers of Red-throated Loons from the west
was well underway. We had time to watch much of the cycle. The loons
would fly, drop into the water west of the bridge, and feed actively as the
water carried them back toward open water. When they were even with one of
the small islands opposite us, they would rise up and fly toward the bridge
again, drop in to feed, etc., repeating this cycle several times. By 3:45
or so, the flow of birds reversed itself. Over a short period of time --
less than five minutes -- the birds stopped flying in and started flying
out, in increasingly large numbers. Within ten minutes, they were gone.
Wow!

How the Red-throated Loons know when the ebb currents at Deception Pass
occur each day is a mystery to me, since the timing changes daily.

Maybe there are factors other than ebb currents that account for the timing
of the Red-throated Loons influx at Deception Pass. I'd appreciate any one
else's observations.

Vicki King
Seattle, WA