Tuesday, January 22, 2013

Warbler Guy, what are occurrence maps? Do warbler occurrence maps exist?

Yes, Carli, Occurrence Maps are present for many North American birds.

(See: http://ebird.org/content/ebird/about/occurrence-maps/occurrence-maps)

As a tool to display the abundance of a species at any given time during the year, these representations
are called STEM (Spatio-Temporal Exploratory Model) maps that address species' occurrences in the Lower 48 states. 

(Prothonotary Warbler Occurrence Map, above; if its functionality does not work for you at this site, then go to the above site in line two and click on "Prothonotary Warbler")
For each species depicted, its migration patterns are accounted for along with its breeding range.

Additional details are necessary to fully explain the Occurrence Maps and STEM.

For now, suffice to say that Occurrence Maps may be a tool you wish to add to your repertoire when identifying wood-warblers.

Monday, January 7, 2013

Warbler Guy, are wood-warblers the smallest songbirds in our area? If not, which songbirds are smaller than wood-warblers?

The answer (Jake, in Dubuque): No.....and Ruby-crowned (and Golden-crowned) Kinglet and Bushtit are species smaller than wood-warblers. Unlike the typically 4- to 5-inch wood-warbler species, both of the kinglets and the Bushtit range from 3.5 to 4.3 inches in length*.

What other small-time songbird candidates are we missing?  What about the Verdin, you say? Or the various chickadees in North America?

Nice try, but the Verdin is 4.5 inches and the chickadees (such as the Black-capped and Mountain) typically range from 4.5 to 5.5 inches in length.

(* = Of course, at 7 inches, the anomalous Yellow-breasted Chat is larger than any of the approximately 56 wood-warbler species you might see annually in North America north of Mexico.)