This is the time of year Sooty Shearwaters begin massing by the countless
tens of thousands all up and down the West Coast and Alaska to remain from
now through summer and well into autumn. How did they get
here?...alone?...or in the company of others? The answer is alone ... one bird at a time.
I think I can confidently state this fact as a veteran of many
mid-subtropical and Equatorial tropical Pacific Ocean high seas research endeavors
year after year over the past 20+ years and having born witness to this
migration day after day after day. And this Spring too, I'm at it again along
with my good Canadian seabirding companion, Michael Force, in the Equatorial
Pacific and a month long marine mammal and seabird research cruise
literally out in the absolute utter dead center middle of nowhere, American Samoa
to Palmyra Atoll / Kingman Reef to Honolulu.

Today is 'humpday', half way through and there has not been one single day
so far since we sailed from Pago Pago on 23 April that the Sooty
Shearwater has not been seen. Ditto too for Mottled Petrel. Day totals for both
are not large, 10-15 Sooty Shearwaters, maybe 3-5 Mottled Petrels per day,
but each and every single one, one at a time, singles and miles apart from
any companion of their stripe.

This long long distance trans-Pacific migration from the New Zealand
breeding grounds to the super rich 'wintering' feeding grounds in the cold
waters of the far north and northeast Pacific appears to span the entire North
Pacific Ocean, a loose sprinkling of countless Sooty Shearwaters, Mottled
Petrels, and a few others, Sooty's bound for 'near-landfall' all along the
West Coast from southern California to the Gulf of Alaska, and the Mottled
Petrels bound for now at least for the offshore Aleutians and an eventual
later trek for some southward via the offshore West Coast and Washington State
(late fall/winter). This is the first time I've had a chance to witness
this northbound high seas pelagic movement in the Spring, having had more
frequent opportunities during many late summer / fall cruises in these same
areas where the pattern remains exactly the same, singles, one at a time,
only in the opposite direction, from north to south instead of south to
north.

One fascinating aspect to this long journey is the seemingly obvious
intense focus on destination. It's all about destination, destination,
destination, whether that destination be the summer time feeding shoals off the
mouth of the Columbia River and elsewhere up and down the West Coast or the
breeding grounds of southern New Zealand, there is absolutely and utterly no
distraction enroute. The nutrient poor crystal clear blue 80F waters of
the tropical Pacific, albeit always very pretty to look at, lacks everything
of even the remotest interest to these long distant migrants. Not even the
huge feeding frenzied swarms of the typical tropical seabirds of the
region which oft-times numbers in the many hundreds randomly scattered about,
like the tropical terns (sooty, white, noddies, etc), tropical shearwaters
(wedge-tailed especially), assorted Pterodromas (up to a dozen or more
species), boobies, frigates, tropicbirds, nor even the presence of the ship
itself will dislodge even the slightest tweak of curiosity among these focused
migrants.

Only with respect to Short-tailed Shearwaters is this lonely bird by bird
migration a bit different. Short-tailed Shearwaters by contrast to Sooty
Shearwaters in trans-Pacific migration remain a bit more gregarious, much
the same as they are on the rich feeding grounds of Alaska and Antarctica
south of Australia where they can carpet huge patches of ocean black in
countless tens, sometimes hundreds of thousands strong. I've only witnessed the
southbound Short-tailed migration and they are indeed often flocked up,
usually as a few dozen to perhaps a couple hundred and I am probably seeing
only the far eastern edge as the main path appears to be just over the
dateline to the west. Regardless, the urgency to cover the distance is no less,
high speed wheeling masses zipping by at 70-100mph absent even the
slightest glance or distraction, so focused it seems at times as to nearly bump
into the ship unnoticed ... no exaggeration!! We saw a few northbound
Short-tailed Shearwaters back around American Samoa but as we've gradually eased
eastward and presently now in the close proximity of Palmyra Atoll and
Kingman Reef for a few days in our ultimate Honolulu-bound trajectory, I think
we must be out of range now for most of the Short-tailed the majority of
which are surely dead-set headed for the far western Alaskan Aleutians and the
Bering Sea along a more westerly track from southern Australia.

Richard Rowlett
currently at sea:
_NOAA R/V "Oscar Elton Sette"_ (http://www.moc.noaa.gov/os/)

06-20N, 162-18W
near _Palmyra Atoll_ (http://en.wikipedia.org/wiki/Palmyra_Atoll)
and _Kingman Reef_ (http://en.wikipedia.org/wiki/Kingman_Reef)