Thursday, April 05, 2007

Larimer County Colorado bird atlases, 1998

Way back in 1998, I did a pair of personal bird atlas projects in what was then my home of Larimer County, Colorado. I used the standard Breeding Bird Atlas grid (USGS 7.5' quads divided into sixths) as my basis. Twice during the year, winter and summer, I spent at least 15 minutes in every block in the county that was accessible by public road. I published my winter atlas results back then on a now defunct web site, that still might be accessible in part from the Internet Wayback Machine. I never got around to publishing my summer results in any form. Now that I have all this data put into eBird, it is finally available online in some form. You can see eBird summaries of my results here:

Winter Atlas

Summer Atlas (no distinction made between breeders and non-breeding summer visitors; includes some late spring migrants)

What you are actually looking at are eBird summaries of all Larimer County records from Dec. '97 through Feb. '98, and May '98 through July '98. So far, I am the only person who appears to have entered any eBird data for the county in these years, so you are just looking at my records for this period. In a funny eBird way, the opening bar graph only list the species found during the specified time period, but shows their occurence for the entire year. The most interesting thing is probably the individual species maps; click on a species name from the table to get the species summary. Then click the Map tab to bring up a presence/absence map of the species, such as this one for Blue Jay in winter:

and this one for Veery in summer:

The dots show the locations of data; green is present, gray is absent. Remember that each point is usually only 15-30 minutes of coverage, so it's a grainy underexposed fast-shutter-speed snapshot, not a detailed time exposure. You can also see how much more extensive my mountain coverage was in the summer than in the winter. There's a lot of interesting detail in the abundance patterns across the county that is mostly lost in the presence/absence maps. Still, I'm glad to finally have this data in a public archive.

As for the missing White-tailed Ptarmigans, I actually did get some on the summer atlas on August 3, but that gets cut off by using eBird's whole month approach. Imagine a single green dot on the western border of the county... pretty close to the single green dot for Brown-capped Rosy Finch in the winter atlas. And the Gyrfalcon? That was a wonderful bird (not originally found by me) at the Rawhide power plant that delighted throngs of birders during its visit.


At 8:47 AM, Blogger Unknown said...


Really cool. The links have actually expired but if you remove the locRSID parameter (&locRSID=RS2228452) then they should work all the time.

At 9:22 AM, Blogger Bill Pulliam said...

Thanks! fixed, I think.

At 8:09 AM, Anonymous Anonymous said...


This is really great stuff. It shows how a single birder can significantly contribute to our collective knowledge of bird distribution over time and space.

Chris Wood


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