[birding] Where are the goldfinches?

[Joel Geier]

Hi Doug & All,

Thanks for the suggestion. eBird can be a useful tool but these maps are
a little tricky to interpret, due to very uneven data support. 

If you compare the maps that eBird generates for the same months last
year, you see a very similar pattern with few detections in Oregon but a
bunch in California and eastern Washington. However, the colors for
those regions, on the 2008 map, are a darker shade of green than the
same areas on the 2009 map. 

Thus it looks like American Goldfinch detections, at least as
represented on eBird, are also down from last year in most of eastern
Oregon and northern California.

My guess is that the apparent concentrations of American Goldfinches in
these areas, in both winters, are mainly an artifact of the relatively
uneven & sparse observer distribution in the Pacific Northwest states.
The eBird folks use a smoothing algorithm (some type of kriging I
suppose) to try to cover the holes in their data set. However in our
region this probably just inflates the anomalies from relatively few
observers over a wider geographic area -- so it turns local contrasts
into regional contrasts.

Happy e-birding,
Joel

--
Joel Geier
Camp Adair area north of Corvallis

On Mon, 2009-02-09 at 08:04 -0800, Douglas Robinson wrote:
> Hi all,
> 
> You can find out where they are by going to www.ebird.org. Click on
> 
> http://ebird.org/ebird/GuideMe?src=changeDate&speciesCodes=amegfi&getLocatio
> ns=northAmerica&reportType=species&monthRadio=on&bMonth=01&eMonth=02&bYear=2
> 009&eYear=2009&continue.x=63&continue.y=6&continue=Continue
> 
> Or go to ebird, click on view and explore data, type in the species name,
> then click change date and select the time period you want.
> 
> Looks like the goldfinches are now in eastern Washington and California.
> 
> Have fun
> Doug
> 
> 
> On 2/9/09 7:04 AM, "Joel Geier" <joel.geier at peak.org> wrote:
> 
> > Hi all,
> > 
> > Thanks to Will, Hendrik, Jeff, Mark, and Randy for replies on this
> > question.
> > 
> > It sounds like Lesser Goldfinches are still around their usual haunts
> > though in somewhat reduced numbers in some places, while American
> > Goldfinch numbers are greatly reduced from recent winters. A check of
> > reports on www.birdnotes.net shows a similar pattern -- there are more
> > counts showing Lessers than counts showing Americans, in western/central
> > Oregon.
> > 
> > Ordinarily there should be one or two flocks of 100 or more American
> > Goldfinches on E.E. Wilson Wildlife area, and similarly big flocks at
> > Luckiamute State Natural Area. I've only seen 2 or 3 in these places
> > since the start of the year. Since these birds can be nomadic in winter,
> > I wonder where they've gone to this year. I didn't see any particularly
> > big flocks in California's central valley a couple of weeks ago.
> > 
> > Happy birding,
> > Joel
> > 
> > --
> > Joel Geier
> > Camp Adair area
> > 
> > 
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>