Outbreak Likelihood - Western U.S.

Slightly elevated

Outbreak Likelihood - Eastern U.S.

Slightly elevated

Salmonellosis Outbreak Likelihood Synopsis

There is a slightly elevated likelihood of a large outbreak in both the Western and Eastern United States (see colored regions below) this year, due to the moderate likelihood of Pine Siskin irruptions in both regions. Our prediction for the 2025-2026 winter is that Pine Siskins are more likely to irrupt in the West compared to the East. Click here or on the “Irruptions” tab above to see predictions for the Pine Siskin and seven other irruptive species.

Likely Outbreak Locations

Historical Outbreak Locations

The likelihood of salmonellosis outbreaks is predicted separately for Western (blue) and Eastern North America (orange). We split the continent based on ecological divisions using EPA ecoregion designations, rather than political borders.

Historically, salmonellosis outbreaks (black dots) are more commonly reported and larger (dot size) in some areas. Hotspots in the Western U.S. are clustered around major cities on the West Coast including Seattle, Portland, and San Francisco. In the Eastern U.S., outbreaks are most often reported in Wisconsin and New England.

Western Irruption Forecast

Irruptions are predicted to be above average for all eight species in the Western region this year (filled circles).

We predict a lower than normal predicted cone crop in the West this summer/fall.

Relatively weak irruptions were observed across all species last year (open circles).

Of all species, White-winged Crossbill is predicted to exhibit the largest irruption.

Eastern Irruption Forecast

Irruptions are predicted to vary across the eight species in the Western region this year (filled circles).

Cone crops are predicted to be around average across the region this year.

Red Crossbills and Pine Grosbeaks exhibited large irruptions last year (open circles), and as a result, our model predicts relatively weak/no irruptions for these species.

Pine Siskins, Evening Grosbeaks, Purple Finches are predicted to exhibit relatively weak irruptions this year.