Hello, Birders.
First off: What a great find! Congratulations to Tim Davis and Andrew Davis for
finding and correctly identifying the bird, and kudos to Joe Roller for getting
the word out so quickly.
Hugh Kingery made an excellent point:
> I've always thought it too bad that an exotic is considered
> guilty until proved innocent (if "proof" is the right word).
Sheesh--you'd think the guy is a lawyer or something... ;)
Seriously, Hugh gets at something quite important. It's essential to start off
with a reasonable assumption, and then to attempt to test that assumption. (Or
even to "prove" it, as in the legal system.) In the U.S. legal systemm, we
start off with an assumption of innocence, and then we go about attempting to
test that assumption.
In science, the procedure is analogous. We start off with a "null hypothesis,"
which we attempt to prove--to *dis*prove, actually. The alternative to this
"null hypothesis" is called--wait for it!--an "alternative hypothesis."
Let's say I'm on the grounds of the Denver Zoo, minding my business and eating
my potato crisps, when, all of a sudden, a splendid Common Grackle and an
equally splendid Indian Peafowl saunter up to me and beg for handouts.
Naturally, my first instinct is to ask this question: "Can I enter these two
species on my Denver County eBird checklist?"
For the grackle, a reasonable null hypothesis, I would say, is that the bird
is, for want of a better term, "wild." That's our base line, our starting
point, our working assumption. To disprove that hypothesis, we would need
information ("data") to contradict the bird's wild status. For example, we
might see that the bird is wearing a band that says "Property of the Denver
Zoo." But, absent such information ("data"), we stick with our assumption (our
"null hypothesis") that the bird is wild.
For the peafowl, conversely, a reasonable null hypothesis, I would say, is that
the bird is not wild. Now, suppose someone points out to us that the bird is
carrying a small radio transmitter. Upon further investigation, we learn that
the transmitter was affixed to the bird in the wild in India, and that the bird
flew nonstop across the Indian Ocean, the Middle East, Europe, the Atlantic
Ocean, and eastern North America (with continuous signal transmission the whole
way), and then landed in the Denver Zoo. In this scenario, we would toss out
our assumption (we would "reject the null hypothesis") of non-wild origin in
favor of the "alternative hypothesis" of wild origin.
The key point is, You have to start with a well-chosen assumption ("null
hypothesis"). The folks who invented our legal system believed that innocence
was a good starting point. In the case of our Denver Zoo birds, it depends on
the bird: I think most people would agree on "wild" for the grackle, but "not
wild" for the peafowl.
So what about the Georgetown Rufous-collared Sparrow? I think it's more likely
that the bird is an escape than a vagrant from Mexico or points south. But I
don't think the odds are overwhelmingly against natural vagrancy, as in the
case of a peafowl at the Denver Zoo. So I'm gonna go with "innocent until
proven guilty" on this one. Now, we already have "circumstantial evidence" for
its "guilt": I'm thinking of Dennis Garrison's link to Rufous-collared Sparrows
for sale in the USA, and Nick Komar's follow-up about I-70 as a good point of
escape for the species. But I think further investigation is warranted. I think
it might be possible to disprove natural vagrancy for this individual not by
circumstantial evidence but rather with an ornithological "smoking gun"--an
eyewitness report that the bird jumped out of a Ryder Truck at Jenny's Market,
or a band that reads "Hecho en Mexico," or something like that.
All that said, I wonder if we're missing the broader point. This bird IS
remarkable. If it flew up here on its own from Mexico (or points south), that's
impressive. (And, just to repeat myself, I do NOT think that's the case.) But
it's also remarkable if the bird is an escape and surviving on its own in lowly
Georgetown. Here's an interesting mini-commentary from Michael Retter's
"Sightings" column, p. 20, in the current (May 2011) issue of Birding magazine:
"A Common Crane was in Buffalo, NE 3/24; this species is more frequently
detected in NE than in any other state or province in North America. An
'uncountable' Hooded Crane was, if anything, even more impressive; the bird
escaped from a facility in ID and got all the way to NE."
Just because a bird is an escape does NOT mean it is somehow unimpressive.
Hooded Cranes in Nebraska, Rufous-collared Sparrows in Colorado...good stuff!
By the way, the most impressive avian story of the past decade in Colorado has
been the astonishing conquest of our state by the Eurasian Collared-Dove--a
population of captive origin, of course.
Let's show this Georgetown sparrow some respect. If it's a vagrant, that's
pretty darned impressive. If it's "just" an escape, it's nonetheless a
beautiful bird, with a gorgeous song, that must be remarkable indeed to behold
in Georgetown; and it's impressive that the bird is, for now, holding its own
up there.
And check this out: There always has to that first pioneer. Nick gets at that
point, although a bit facetiously. But, seriously, at some point, a Eurasian
Tree-Sparrow got it all started in St. Louis; a Eurasian Collared-Dove got it
all started in Florida (and, before that, in the West Indies); a Peach-faced
Lovebird (coming soon to a checklist near you!) got it all started in Phoenix;
and--who knows?--maybe, as Nick has said, a Rufous-collared Sparrow will have
gotten it all started in Georgetown. Again, let's show this bird some respect.
Even though it's probably "just" an escape.
A final thought. Christian Nunes said in a recent post to COBirds: "Humans have
their fingers in everything, if you haven't noticed." I agree, but with a
twist. Yes, we have our fingers in everything--and that ought to affect our
perception of birds that we have traditionally thought of as "wild" or
"natural." Think of a "wild" vagrant hummingbird at a feeder in New York City
in January: Everything about that scenario is overwhelmingly *un*natural. NYC,
for starters! And the plastic feeder. And the "hummer juice." And human-caused
alterations to the landscape and the climate--affecting not only the individual
hummer, but indeed the behavior and ecology of the entire species.
By extension, the next time you see a "wild" vagrant at Prewitt Reservoir,
consider just how profoundly *un*natural that occurrence is. A Long-tailed
Jaeger flying around an artificial reservoir in Colorado is profoundly
human-influenced, in the same manner as a Rufous-collared Sparrow that escaped
from an RV in Georgetown.
For further thoughts on the matter, check this out:
http://aba.org/nab/v64n4p548.pdf
If nothing else, you will encounter the longest word ever to have appeared in
the title of an ABA publication!
-------------------------------
Ted Floyd
Editor, Birding
Blog: http://tinyurl.com/4n6qswt
Twitter: http://tinyurl.com/2ejzlzv
Facebook: http://tinyurl.com/2wkvwxs
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