Hi all:

Being responsible for the filters used by eBird to determine for entries which 
species are regular for time and place and which are not, I decided last year 
to change how certain aspects of those filters are presented in relation to a 
few species, particularly Willet and Fox Sparrow.  Willet is a 
rare-and-localized breeder in the state, but a common (and widespread) migrant. 
 As far as anyone knows, all occurrences of the species in the state refer to 
the western subspecies inornata, known colloquially as Western Willet or, in 
eBird parlance, 'Willet (Western).'  The eastern subspecies has not been shown 
to occur and is an exceedingly unlikely candidate for vagrancy to the state.  
Thus, essentially, all Willets in the state are Western Willets, so I have 
altered all of the state's eBird filters to allow for 'Willet (Western)' but 
NOT for the straight-up species category, 'Willet.'

One monkey-wrench that this action creates is that anyone entering data needs 
to check the 'Show Subspecies' box in the checklist view when entering data.  I 
have provided an example of this in a screen capture 
(http://www.flickr.com/photos/tony_leukering/9119119084/).  This picture also 
shows that the 'Show Rarities' box is checked, thus showing the straight-up 
Willet entry (which is noted as 'RARE'); this entry would not appear without 
that box being checked.  The entry in this checklist for Willet is indicated by 
the left arrow, pointing to the 9 Western Willets at Barr Lake, Adams Co., on 
24 April 2004.  This subspecies entry would not appear without the 'Show 
Subspecies' box being checked.

Fox Sparrow presents something of a slightly different treatment, as at least 
two forms of the species are found annually in the state:  Slate-colored Fox 
Sparrow [in eBird, 'Fox Sparrow (Slate-colored)] and Red Fox Sparrow [Fox 
Sparrow (Red)].  However, the two forms are virtually never in the state at the 
same time (barring the odd wintering Slate-colored Fox Sparrow that seems to 
like the McConnells' yard).  Slate-colored is the breeding form in the 
mountains and is present, typically, from some time in April to some time in 
September.  Despite this form's breeding occurrence in the mountains, it is 
exceedingly rare on the plains and fairly rare anywhere as a migrant.  This 
form seems to be able to come and go from the state without making stopovers 
outside breeding elevations and habitat, though that is somewhat less true on 
the West Slope than it is in eastern Colorado.  Red Fox Sparrow, a form for 
which the Colorado Bird Records Committee requests documentation, is of annual 
occurrence in very small numbers, primarily on the plains, typically as a fall 
migrant in Oct-Nov, but with a bird or two in some winters.

Because Fox Sparrows of any sort are rare on the plains, the Colorado eBird 
filters for that region do not allow for the species at all, and one must check 
the 'Show Rarities' box to have any Fox Sparrow category visible for entry.  In 
the montane counties, Fox Sparrow (Slate-colored) is allowed by the relevant 
eBird filters for the time that the form is typically in those areas.  Since 
nearly all of the Fox Sparrows found during that time period (~April - 
~September) are local breeders or progeny thereof, no other category of Fox 
Sparrow is permitted by the eBird filters for montane Colorado; one must check 
the 'Show Rarities' box to have any other categories become available.  I have 
provided an example of Fox Sparrow from a checklist from Jersey Jim Flats, 
Montezuma Co., on 7 July 2006, that shows the 'Show Subspecies' box checked and 
the filter-allowed Fox Sparrow entry 
(http://www.flickr.com/photos/tony_leukering/9119054654/in/photostream/lightbox/).
  The species-level category ('Fox Sparrow') would have been available had I 
checked the 'Show Rarities' box.

I did all of this to prepare Colorado eBird data for the possible/probable 
split of such species.  I am preparing to perform similar filter tasks for Sage 
Sparrow, because it seems likely that the American Ornithologists' Union will 
accept the proposal to split that species.  As far as we know, all Colorado 
records of Sage Sparrow are of what would be the interior species (whatever the 
AOU would decide to call it, perhaps Great Basin Sage-Sparrow).

Thanks for your attention and for using eBird!

Tony Leukering
Colorado eBird reviewer
San Clemente Island, CA


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