[Tweeters] Olympic coast seabird survey

B Boekelheide bboek at olympus.net
Sun Jun 19 23:14:35 PDT 2016

Hello, Tweeters,

Yesterday, 6/18/16, I was fortunate to help with a seabird survey out of La Push with Olympic Coast National Marine Sanctuary, on their boat R/V Tatoosh. The cruise track went WNW from La Push across the Juan de Fuca Canyon to about 40 miles offshore, jogged north about 10 miles, then 40 miles back to the coast near the vicinity of Sealion Rock, and eventually back to La Push along the coast. Other observers were Scott Horton (WDNR biologist) and Sue Thomas (USFWS biologist). Sanctuary science coordinator Liam Antrim and NOAA marine technician Kathy Hough entered data as we relayed it through the cruise, and LTJG Alisha Friel ably skippered the boat. We followed standard seabird survey protocol by counting birds within 300 m on one side of the boat. The weather cooperated superbly, with passing squall lines, low winds, and excellent visibility all day.

Most interesting sighting for me was an Ancient Murrelet family swimming together about 40 miles offshore, with two adults and two almost-grown gawky-downy chicks, paddling around far offshore on the deep blue sea. These birds could have nested on the Olympic Peninsula, or they could have come down from Canada - we’ll never know. There have been other sightings of Ancient Murrelets with chicks offshore of the Olympic coast in recent years, including a small chick riding on its parent’s back seen by Scott Horton a few years ago, so they are likely nesting here somewhere. I believe the only Ancient Murrelet nest ever found in Washington was at Carroll Island in 1924.

Next, there are tens of thousands of shearwaters off the Olympic Coast right now, concentrated about 20-25 miles offshore at the Juan de Fuca Canyon. On both the outbound and inbound legs we encountered very large flocks of Sooty and Pink-footed Shearwaters in the same relative area. Within just our little 300 m strip we counted several thousand shearwaters, yet the birds were visible at times as far as we could see in different directions. In the light winds, they mostly just sat on the surface or flew in different directions as we passed by. We never saw distinctive feeding activity. Considering the density of birds within our transect, and the area over which they covered, our conservative estimate for the overall area was 40,000 Sooty Shearwaters and 5,000 Pink-footed Shearwaters. There easily could have been many more.

Conversely, there were some areas with very low bird densities, particularly far offshore in the early afternoon, and on some continental shelf areas away from the Juan de Fuca Canyon. Some of the far offshore areas may have even had higher densities of Humpback Whales than birds.

Other birds spotted with the shearwater flocks included one Manx Shearwater and 3 South Polar Skuas. I don’t have the final tallies, but there were only about 10 Black-footed Albatrosses, 10 fulmars, and 50 Fork-tailed Storm-Petrels for the whole trip, along with about 20 Cassin’s Auklets, 30 Tufted Puffins, 40 Rhino Auklets, 300 murres, and one Heermann’s Gull (in addition to the usual gulls and cormorants). No sign of post-breeding dispersal from the Arctic yet, so no jaegers, Sabine’s Gulls, terns, or phalaropes. Marine mammals put on a great show near the shearwater flocks and offshore, including about 15 Humpback Whales, 30 Risso’s Dolphins, at least 100 (and likely many more) Pacific White-sided Dolphins, a pod of 6 Dall’s Porpoises that rode our bow for several minutes, and 2 Northern Fur Seals. Closer to shore we spotted a pod of 4 Orcas south of Jagged island and one sea otter off Carroll Island. All-in-all, a great day on the ocean.

Bob Boekelheide

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