Fan-tailed Warbler. Photo: Janine McCabe.
The results of the Global Big Day spring migration count in Arizona (formerly North American Migration Count) are presented here by AZFO. For 12 years, we coordinated the NAMC in Arizona, supported by local Audubon Societies, local bird clubs, and other interested organizations, and compiled the data county by county on the AZFO's website. Since 2016, we've merged our experience into eBird's Global Big Day, which has built on what we have accomplished and provided a new opportunity to expand what we have achieved by making our statewide count part of a broader international, effort. With hundreds of volunteers in the field, we aim to get a "snapshot" of spring migration, gather information on the distribution of each species, get teams to locations not regularly birded, and Have Fun!
Annual Report: Global Big Day Count in Arizona
May 10, 2025
By Doug Jenness
In Arizona hundreds of volunteers, many of them coordinated in teams on a countywide basis by AZFO, tallied 308 species during the Global Big Day spring migration count on 10 May 2025, which was an excellent showing.
Three new species were added to the 22-year cumulative state list for the North American Migration Count/Global Big Day in Arizona. They were Hudsonian Godwit (Gila), American Golden-plover (Cochise), and Baltimore Oriole (Coconino). Forty-six species from 13 counties were reported from only one county. The number by county was Cochise (19), Santa Cruz (8), Coconino (4), Maricopa (4), Apache (2), Gila (2), Yavapai (2), Pinal (1), Pima (1), La Paz (1), Mohave (1), and Graham (1). Two counties scored their highest number of species in 22 years: Cochise (231) and Pinal (191). Twenty-four species were reported from all 15 counties. Arizona had the third highest number of species in the United States after Texas (420) and California (364).
The movement of passerine migrants was better than usual. Figures tallied for three of four wood-warblers that migrate through but are not known to nest in Arizona were above average. For Nashville Warbler we tallied a 22-year high (12). Totals for Townsend’s (227) and Hermit (47) warblers were well above average. Wilson’s Warbler (626) was the highest in four years and slightly above average.
The accompanying Excel spreadsheet has a page comparing the 2025 county totals for each species and. compares the number of counties each species has been reported by year since 2006. Many volunteers were in teams coordinated on a countywide basis by the AZFO. We'll be looking forward to your participation in the Global Big Day in Arizona 2026 on Saturday, 9 May.
Baltimore Oriole, Coconino County. Photo: Jason Wilder.