** Reply to note from Dennis Paulson

>
> This is forwarded from Bill Smith, who recently spent some time in our
> region and thus has been browsing tweeters from time to time. He tuned in
> to the discussion about vagrants (perhaps with vested interest, as he saw
> the hummingbird).
>
> I should add that the probably hurricane-borne Black Swift that Jack
> Bowling cited from New England is indeed a bona fide West Indian land bird
> on the North Atlantic coast. However, it's not a *resident* West Indian
> land bird. This is a *migratory* species, spending only the summer in the
> West Indies. Thus the bird displaced could easily have been migrating over
> the ocean and does not represent evidence contrary to what I have been
> saying and what Bill reiterates below.

<snip>

Bill Smith writes -

> >Dispersal of survivors trying to deal with the impact of a storm or other
> >phenomena like volcanic eruptions on food sources, after the fact, is
> >another issue, but I'm not aware that off-island displacement has ever
> >been proven even in that more likely scenario. There may also be some
> >displacement of some species as a result of high winds, but that's not
> >quite the same as saying that a hurricane sweeps a bird off its
> >perch and deposits it alive, hundreds of miles away.

Umm, excuse me, but that is exactly the argument here. It is pure semantics
to conjure up some difference between "displacement of some species as a
result of high winds" and "a hurricane sweep(ing) a bird off its perch and
depositing it alive, hundreds of miles away". It is very likely that there
is a threshold wind speed over which any land (and sea) bird would be
nuked, that threshold lowering with the decreasing skeletal resiliency of
the affected species. Where would a hummer fit in on this scale? Don't
know. But they are tough little buggers, as are their close cousins swifts.
We seem to have no problem accepting the fact that anything over open water
is fair game to be swept along by a hurricane. It is very hard to believe
that landbirds *never* get swept out to sea by storms, especially when
considering the dearth of forest to take cover in on the narrow Baja
peninsula. It is still quite easy to believe that the Xantus' in question
was swept off the coast (either east or west depending on if it happened
with the approach or departure of the hurricane), especially considering
that Nora was winding down rapidly by the time it got to Baja latitudes,
thus increasing the chance that its mortality threshold wind speed had not
been maintained. Yes, there may be little to no historical precedent for
landbirds getting towed along by hurricanes and surviving the trip, but
that *does not* _a priori_ mean that it could never happen.

> >
> >Yet birds do strange things. The first LaSagra's Flycatcher in the USA
> >was of the Cuban race, in non-coastal Alabama, not storm-related (Miles,
> >M.L. 1967. Auk 84: 279).

Strangeness is truly a human concept.

- Jack

Jack Bowling
RR1-S14-C41
Prince George, BC
Canada
V2N 2H8
phone: (250) 963-7837
fax: (250) 963-7801
jbowling at direct.ca

cc: dpaulson at ups.edu