Long, long ago, in the lead-up to my first Colorado Christmas Bird Count (Boulder CBC, Sunday, Dec. 15, 2002), Bill Kaempfer made two remarks that have stuck with me all these years. (He undoubtedly made more than two remarks, but two in particular found immediate and permanent residence in the limbic system of my brain.) Anyhow, he told me that (1) Black-billed Magpie and Northern Flicker are the only two species to have been reported on every single Boulder CBC and that (2) Bushtit would be a "choice bird" on the CBC.
The Black-billed Magpie and Northern Flicker continue their streak, but the Bushtit, although a supremely cool bird, is no longer a choice bird on the CBC, being reported every year now by multiple parties.
This chilly, sunny Saturday morning, Feb. 25, Andrew Floyd and I inadvertently commemorated the wisdom of Kaempfer by seeing three species building nests at Hecla Lake, Boulder County. Sure enough: Bushtit, Black-billed Magpie, and Northern Flicker. Photos of the nest-builders here: http://ebird.org/ebird/view/checklist/S34794003.
Later in the day, in the planted conifers at the intersection of 109th Street and Jasper Road, eastern Boulder County, I saw a single Harris's Sparrow in a flock of juncos and White-crowns. Also a pair of Bushtits there.