The Verde River Watershed is home to one of the rarest forests on Earth, the Cottonwood-Gooding Willow Gallery. Formed by the connection between the river and its desert surroundings, these forests, when healthy, support an incredible diversity of bird species. To measure riparian forest health, we compared the current number of bird species in a region to a list of species expected to nest in the riparian area of the region.
How is it scored?
A list of unique bird species that nest in the riparian forests of the Verde River Watershed was compiled from the Arizona Game and Fish Department's Element Occurrence database and the Arizona Breeding Bird Atlas. Combined, these databases provide what we called a baseline list of bird presence for each watershed zone. For each species, we identified the breeding season.
To compile data for riparian birds observed in the past two years in each watershed region, we used observations documented in the citizen science app eBrid. We filtered the observations to only include birds from the list that were observed during their respective breeding season. The indicator score represents the percentage of birds from the baseline list that were seen within each region over a two-year time period.
The Riparian Bird methodology changed slightly between 2020 and 2025. The main changes involved updating the taxonomy to the most recently accepted taxonomy for the species of interest, removing sensitive species from the species list (as exact locations were unavailable from eBird), and correcting errors in the breeding season for some species. The removal of sensitive species for which eBird locations were unavailable resulted in a slightly smaller list of species than what was used in 2020. To account for this slight revision to the methodology, the scores for 2020 were recalculated using this updated list of birds.