We are thrilled to share our 2017 STEM models, which are the product of several years of refinements and improvements. STEM (Spatio-Temporal Exploratory Model) is a species distribution model that has been specifically developed for eBird data by statisticians and researchers at the Cornell Lab of Ornithology. These models were first released in 2009 and have since been used in a number of papers and reports including three State of the Birds Reports, most recently in 2016.
These new models have a large number of improvements, most notably: 1) coverage of the entire Western Hemisphere; 2) model predictions of abundance, instead of occurrence or frequency (which is why counting birds matters!); 3) predictions of bird occurrence at finer scale than before (formerly 30km, now 8km), making for more detailed maps; 4) use of new statistical techniques to mitigate effects of overextrapolation.
Each pixel in these models gives a specific prediction for the expected number of individuals you could expect to encounter at a given location if you went birding for 1-hour at 7am covering 1 kilometer of distance. Our Help Center has more information on STEM models.
Wood Thrush is a well-known forest species, especially so in the eastern United States where its melodic song rings through eastern forests from May to July. It migrates to Central America for the winter, where it also prefers dark, close-canopy broadleaf forests, very similar to its breeding grounds. During the winter it is much less conspicuous, largely detected by its chattering call notes and occasionally flushed from forest trails.
Indigo Bunting (Passerina cyanea) is a familiar summer bird in the eastern United States and southern Canada, with males sporting an almost unnatural hue of bright blue that is richer on the face than on the breast and back. In the fall and winter males lose their blue plumage and resemble the brown females.
Barn Swallow may be the most widespread and well-known passerine, with highly migratory populations that span the Americas as well as Europe, Asia, and Africa. Related species, and some Barn Swallow subspecies, are resident in Africa, the Middle East, and Australia. This remarkable variability makes Barn Swallow a great case study in migratory behavior. The varied migratory behaviors in this species globally are also seen on a smaller scale in the Americas, as this new STEM map helps illustrate.