Hi Tweets,

Denny Granstrand writes:

>In all of the excitement over this cute little hummer, has anyone considered
>that it might have escaped from an aviary? I have a hard time visualizing a
>hummerbird from Baja getting lost and showing up at a feeder in B.C.

Yeh mon, I've been biting my tongue, waiting for someone else to bring this
up! After the Tropical/Couch's Kingbird exchanges, I've been hesitant to
rain on any happy little parades. Well, truth is, we'll never know for sure
whether this is a genuine vagrant or a somehow-assisted or released bird.

In support of it being a bona fide vagrant are two inferential reasons, one
major, two minor: the first is that, in southwest BC, as in Nova Scotia,
late Autumnn is traditionally the big month for deep southern strays; the
first lesser reason that local aviaries don't (legally) keep hummingbirds,
the second that juveniles tend to be the more migrationally incompetent.

Against is the degree of likelihood of a distant sedentary species showing
not only no previous long-distance pattern of vagrancy, but no pattern of
post-breeding dispersal. How *else* could such as species appear so far
north in unlikely habitat but some kind of artifical assist, either
inadvertent or deliberate? It suddenly appears at a time when there's been
no assisting weather systems other than a clapped-out hurricane almost a
month ago. There's been no wreck or fallout of similar Baja or desert birds
between California and Cascadia, which would have likely happened along the
coast or in the interior if such a system had been the assisting mechanism.

The point that this bird is so out-of-pattern invites discussion. What if
this bird has hybrid genes from some way back where one of the parent
species is migratory and is sometimes a long-distance vagrant? I'm an idiot
when it comes to this kind of stuff: would those who know the field of
genetically-inspired behavior please comment on this possibility?

How else? Well, what are the ways of transport between here and Baja
California in which a hummingbird is likely to survive? Wandering into a
northbound aircraft before take-off (wheel-well, baggage hold) would be
quickest and the way most likely to show a live bird at the destination. A
northbound truck? An unbeknownst passenger in the trunk of a returning
vacationer's car? A torpid hummingbird *might* survive the trip. Deliberate
transport and release? Well, nothing's impossible, as the Hastings Rarities
proved, but the pattern of observation suggests otherwise, and virtually
impossible to establish either intent or commission: that's a far-left-field
possibility, about at the warning track, I'd say. A smuggled bird that
escaped? More possible than the previous, and there's enough precedent
around Vancouver International Airport to support the hypothesis. An escapee
from an illegal clandestine aviary? Not at all impossible: it would be
easier to find homegrow marijuana than illegally-kept birds.

On the strength of this one sighting, more I think about it, it's an
exceedingly difficult call to decide whether either side of the assisted/non
assisted origin question has the more compelling argument. This is one of
those sightings that we'll have to wait about another twenty to fifty years
to see if this sighting is just the first of a developing pattern.

Discussion?

Michael Price We aren't flying...we're falling with style!
Vancouver BC Canada -Buzz Lightyear, Toy Story
mprice at mindlink.net