Tweets, I apologize for the entire quote, but I did not want anything out of
context...


** Dennis P. wrote -

>
> Jack Bowling wrote:
>
> >** Dennis Paulson wrote -
> >>
> >> I thought readily apparent El Nino effects were limited to oceanic
> >> creatures such as fish and birds. They are affected by changes in oceanic
> >> food resources brought about by temperature changes and are big enough to
> >> be noticed. One might consider a Brown Booby a likely vagrant from these
> >> changes, although I hadn't noticed an increase in booby records in
> >> California recently. Has there been a booby incursion farther south? And
> >> how far are birds likely to vagrate (to coin a new verb) under these
> >> conditions? Brown Pelicans, Heermann's Gulls, and Elegant Terns have always
> >> flown north during their nonbreeding season, and the terns are merely
> >> following a normal pattern but flying farther when they come up our way,
> >> perhaps because they don't find enough to eat in California.
> >
> >A narrow view of things, Dennis. I am sure the floods in Africa, the drought in
> >Australia, and the smog from forest fires in Indonesia are all "readily
> >apparent
> >El Nino effects" to the inhabitants of the affected areas, both human and
> >otherwise. As for the vagrancy of Elegant Terns, etc., it is not the fact that
> >their is an annual vagrancy, but the statistically significant increase in
> >numbers of vagrants during an El Nino. I believe Mike Patterson has already
> >crunched some numbers for his section of Oregon.
>
> Sorry, I shouldn't be in such a hurry. My sentence should have read
> "Effects that we can perceive *in this region* having to do with
> macroscopic animals and apparently attributable to El Nino seem limited to
> oceanic fish and birds." Notwithstanding hurricanes on the W coast of North
> America, the changes in our weather due to El Nino are not outside the norm
> for this particular region. I do indeed know about these other effects, but
> my comments were intended to refer to the pattern of bird occurrences under
> discussion.
>
> Of course Elegant Terns increase during El Ninos. That's what I said. Their
> normal postbreeding migration is to move north along the California coast
> in summer, then back to Baja in fall. They are just going farther in El
> Nino years.

Changes are not outside the norm? Not sure about that. This is an especially
strong El Nino. If one were to accept that the increase in vagrancy were tied
to El Nino, then there would be a direct relationship. But apparently this is the
crux of the matter - you cannot accept that there is anything that anomalous
about bird distribution this El Nino season. I would suggest we take a wait-and-
see attitude on this until the whole story is reported and unravelled over the
next few months.

And as for other macro effects, during strong El Ninos there is usually much
less snowfall than normal over the interior of BC which affects the distribution
of field hunting birds such as Short-eared Owls, Northern Shrikes, etc. This
has certainly been the case this event in the Prince George area with an
eightfold increase in Short-eared Owls on the local CBC compared to the longterm
average. Again, the fact that Short-eared Owls stay this far north in warm years
is not in and of itself unusual, but the magnitude of the anomaly is
unprecedented.

> >> We've had some pretty severe El Nino years in the past decades without any
> >> apparent vagrancy, right?
> >
> >I would imagine so due to the fact that one El Nino is always different in some
> >respect than another. There is just too much chaos in the system to expect
> >that the same exact conditions would ever repeat themselves.
>
> Yes, but the effects are, in fact, rather predictable in the Northeast
> Pacific--rising water temperatures and according crashes in some of the
> food webs. I haven't read or heard of any other (again) readily apparent
> effects having to do with wildlife.

> >> Am. Oystercatchers might be affected by changes in intertidal food
> >> resources, but I had not heard of El Nino causing this to occur, and this
> >> species has remained rare in California even with the increase in birders
> >> there over the years. Nevertheless, I see it as a real possibility. Some of
> >> you may not know about the record from Idaho in April 1981, a really
> >> shocking occurrence. It would be great if the Marysville bird could be
> >> relocated and photographed to be sure of the subspecific (and even the
> >> specific) identification. I don't suppose the observer thought of
> >> distinguishing between American and Eurasian as this surprising bird flew
> >> past.
> >>
> >> Of course, caracaras and hummingbirds wouldn't be affected by marine food
> >> resources.
> >
> >Unless there were Caracaras which subsisted on seaside carrion...
>
> Are you writing this tongue in cheek? There's a lot of seabird (and fish?)
> mortality during El Nino years, so I would think a caracara would do just
> fine staying where it was.

Yes. Sorry. Forgot the smiley :-)

> >> El Nino, of course, also changes weather on a broad scale. Is there
> >> anything about weather patterns in, say, northern Mexico, that would
> >> increase the likelihood of vagrancy?
> >
> >Well, "Nora", for one, brought 300 mm of rain in 24 hours to the southern Baja
> >when it crossed. The return period for such an occurrence is likely at least
> >100 years. And many west coastal sections of Mexico were inundated by floods
> >last summer. Perhaps a historical food source of either the hummer or caracaras
> >was affected.
>
> But surely not enough to make them move >1,000 kilometers! I can't believe
> the first hummingbird feeder to be encountered by a moving XAHU would be in
> BC! And caracaras eat just about anything.

OK. Time to detail just how unusual this past hurricane season was in the
eastern Pacific basin. Normally during El Nino years, hurricanes spawn well off
west coast of Mexico and travel westward toward Hawaii. Most never make it there
before they die out. In 1997, not only were there more cyclones that made it to
hurricane strength, but at least two of these - Linda and Nora - attained
Category 5 status i.e. peak winds reaching 160 knots or more. And not only was
the strength of these hurricanes unusual, but their trajectory was also
anomalous.

I include here a summary of the Northeast Pacific 1997 tropical storm season as
provided by the UK Met Office at the following URL:

http://www.meto.govt.uk/sec2/sec2cyclone/tcbulletins/dec97.html

" The charts below show storm tracks for the four northern hemisphere
basins. The number of tropical cyclones (including tropical depressions) was
less than last year. However, the number reaching tropical storm strength or
above was identical. The tropical storm count for the North-West Pacific was
identical to 1996, but the distribution of these was different. Far more
occurred in the east of the basin towards the dateline and far less in the
South China Sea area. In the North-East Pacific there was more activity and
storms tracked further to the north and west than in the previous two years.
There were also two tropical storms which developed in the Central Pacific area
and tracked into the North-West Pacific. North Atlantic activity was
significantly lower than the last two years. These variations in Pacific and
Atlantic activity between this year and the previous two years are what would be
expected following the onset of El Nino conditions."

Individual gif images of all 1997 season tropical storm tracks for each basin can
be viewed at the same location. Note that the western Pacific basin was even more
anomalous than the east side with at least three Category 5 typhoons/hurricanes,
and many that were swept into the prevailing westerlies toward the west coast as
they became extra-tropical.

And in a correction to a previous post of mine, Nora did not travel across the
heart of the Xantus' Hummer range. Rather it travelled northward paralleling the
west coast of Baja before crossing inland over extreme northern Baja. This
subjected all of the Baja except the extreme northern part to the easterly winds
in the east quad of the storm. Since most hurricane-transported birds are
dragged along the trajectory of the east quad of the storm ("with" the storm),
this would suggest that the Xantus' would more likely have been transported
northward via a land route rather than westward out to sea.

> So, yes, a caracara or a Xantus' hummer might migrate up here, but I can't
> for the life of me see how this could be tied in to The Child.
>
> >> Parenthetically, with the abundance of Caribbean hurricanes, and the high
> >> frequency of Caribbean and Atlantic seabirds being seen up and down the
> >> Atlantic coast and even inland (see the last Field Notes), I don't recall
> >> reading about a single West Indian *land bird* turning up north of Florida
> >> on the Atlantic coast. The Bahamas are full of land birds that don't occur
> >> in the U. S. Does anyone know of such records? Perhaps this should be our
> >> clue?

Well, the article in Field Notes by Brinkley, Hass, and Lockyer which you
mentioned includes one such bird deposited by Bertha. I quote from the last
paragraph of the Bertha segment on page 821 (note: 1996 season):

"Certainly the rarest of the year's storm-waifs was deposited by Bertha: a bird
identified as a (West Indian) Black Swift, _Cyseloides niger niger_, at
Chappaquiddick Island, Martha's Vineyard, Massachusetts, on July 14 (Forster
et al. 1996)."

> >Hurricanes are usually a boreal late summer and fall occurrence. At that
> >season,
> >most boreal-breeding migrants are on their way south, not north. In fact, in
> >El Nino years the Atlantic hurricane mechanism is suppressed while the east
> >Pacific basin enjoys an increase in hurricanes - exactly what happened in the
> >summer and fall of 1997. I take it you mean the Field Notes edition which
> >summarizes the fall of 1996 season (spring 1997 edition).

Let me correct myself here and apologize to Dennis. I had not yet read the
lead article about hurricanes and vagrancy in the latest edition of Field Notes,
due to the fact that I always start at the back of a magazine!

> I'm not talking at all about boreal-breeding migrants, but resident endemic
> West Indian birds, none of which--to my knowledge--has *ever* been reported
> north of Florida, right next to the Bahamas. With the number of West Indian
> land bird species that might be picked up by a hurricane, and there have
> been many, and reported by the birding community because they weren't
> species normally seen in the area, I think that's pretty strong evidence
> against hurricanes transporting land birds *away from where they are
> resident.* (emphasis intended). Of course they carry land birds that are
> migrating over water at the time; they've got no choice. You said yourself
> that land birds ground purposely during heavy weather." So how did the
> caracara and hummer (not to mention oystercatcher, which also wouldn't be
> flying out over the water somewhere when a hurricane came) get here?

Ah, yes, sorry. I misinterpreted your original post. See above correction to
trajectory of Nora. It becomes more of a landbound route now.

> Sorry I'm not reading the comments of others, too, but I appreciate Jack's
> forwarding his message to me. Let me know if you're tired of my popping in
> unannounced from time to time!

Dennis, the day that you have to apologize to Tweeters for posting is the day I
quit participating. I think I speak for all Tweets when I say that we miss your
regular input and only wish that your schedule allowed you more frequent visits.

- Jack

------------------
Jack Bowling
Prince George, BC
jbowling at direct.ca

cc: dpaulson at ups.edu