Early
Rufous in Idaho: Two-Way Talk
Mike Patterson of Hummingbirds
and Flowers and Stacy Jon Peterson of Trochilids:
Winter Hummingbirds
Background
On April 5, 2004, Julie Clark sent this report to Mike Patterson, who
studies Rufous hummingbird migration: "A very aggressive and hungry
male rufous hummer is looking all over for his feeders. They're going
up now!" Julie lives 17 miles south of Lewiston, Idaho. Her report
sparked curiosity between Mike Patterson and another hummingbird expert,
Stacy Jon Peterson. Imagine you are a scientist trying to explain this
early arrival. Start by reading their email exchange below.
Two-Way Talk Between Experts
Mike:
This is 8 days earlier than any record I have for Idaho.
Stacy: This is the second earliest that I'm aware of.
I have a few other reports that seem credible that come close,
including the earliest (March 27, 1994) from Mission Flats, Kootenai
County. See all reports that I know about by clicking
here. As you'll note, there's also an April 6 (1989) report (I hesitate
to use the word "record" as I have virtually no documentation
or support of these sightings other than observer credibility) and
an April 8 (2002) report. I'm trying to get more folks to report stuff,
as I think that we may be missing more "early" reports from
previous years...
My thinking on this is mixed. The west coast Rufous have barely made
it over the Cascades, according to Mike's excellent arrival records
for this year, so Julie's bird near Lewiston is unlikely to have come
from that direction it would appear. I wonder if we might need to consider
that these extreme early Rufous in Idaho may have origins in the southeast
instead of the south via the West Coast... Over 1000 Rufous-type hummingbirds
were reported
from the "East" this past fall and winter. Perhaps one
of these birds wintering in Louisiana or elsewhere just took a straight
shot over the Rockies instead of moving west to So. California and then
up the coast with the rest of the conspecifics.
Mike: Lewiston is right on the Snake River so it's also possible, given the remarkably warm weather we've been having, that this bird just ran right up the gorge. Generally, when we get early east side [of the mountains] reports they're from the Columbia Basin.
Stacy: And since the bird was apparently inspecting for a feeder in the yard (presumably at sites where the feeders were present last year), it's possible that this bird was familiar with the site. We know that that site fidelity along the migration route is very strong (birds returning to the same feeder sites along the way), so perhaps this bird "knew where it wanted to go" and made haste given the good weather, as you suggest.
Mike:
I am sure that a few of the East Coast over wintering birds may bee-line
across the Continent (though the Rockies would be a formidible challenge)
or hang a right somewhere in Arizona just past the Rockies, but a pattern
is slowly emerging (in part because the the report density is so low)
for a second wave across New Mexico and Arizona and into central California,
occuring in late March that represents the SE bird, at least, which
seem to linger in Louisiana well past peak movements along the west
coast. These birds are almost never reported north of Tuscon or in interior
spots like Las Vegas or Reno, which suggests that they occur, at best,
in densities low enough to be missed among the Black-chins and Broad-tails.
Stacy: The longer you collect and map these reports,
Mike, the better we'll be able to answer some of these questions. Keep
up the good work!
Try This! Role Play
Work in pairs or small groups. Each partner (or half of the group) chooses the role of either Mike or Stacy. Think carefully about what they're saying as you do further research on your own. Find maps that show the areas they are talking about. Then come back together. Read the conversation aloud, and continue it beyond what you see on this page. Show what you learned, and what you still wonder about.
How do the two scientists build on each other's ideas and comments? Help each other do this in your pair or group.
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