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Fan-tailed Warbler_JanineMcCabe.JPG

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 11, 2024
By Doug Jenness

In Arizona hundreds of volunteers, many of them coordinated in teams on a countywide basis by AZFO, tallied 289 species during the Global Big Day spring migration count on 11 May 2024. This was the lowest total in the state for the annual count since 2012. However, a notable bright spot was that Coconino County reported a 21-year high number of species (192). Moreover, it found White-rumped Sandpiper, only the second time it has been recorded on the migration count, and a Chestnut-sided Warbler, only the third year for the count. Cochise County, which tallied the most species of any county, registered one of its highest totals (225).

White-rumped Sandpiper. Photo: Arthur Gonzales.

Three new species were added to the 21-year cumulative state list for the North American Migration Count/Global Big Day in Arizona. They were Ferruginous Pygmy-Owl (Pima), Eastern Kingbird (Cochise), and Red-eyed Vireo (Cochise). The effort in La Paz County was weak and we only got five species there, and we lacked county coordinators for Greenlee and Yavapai counties. One of the results was that we only had three species found in all 15 counties (European Starling, House Sparrow, and Great-tailed Grackle), which was well below our average. Only 12 species were reported from 14 counties, a smaller number than usual. However, Cassin’s Vireo (10) and Gray Vireo (7) were reported in the most counties in the past 21 years. Only four counties reported Loggerhead Shrike, a 21-year low. Thirty-six species were reported from only one county. The number by county was Cochise (10), Coconino (6), Maricopa (4), Pima (4), Santa Cruz (4), Apache (2), Navajo (2), Yuma (2), Gila (1), and Yavapai (1). In previous years, Arizona has had the third highest number of species in the United States. This year it was fourth after Texas (408), California (372), and Oregon (295).


The movement of passerine migrants, like last year, was not exceptional. Figures were tallied for four wood-warblers that migrate through but are not known to nest in Arizona. They were about average and better than last year for Nashville Warbler (5), Hermit Warbler (11), and Townsend’s Warbler (89). Wilson’s Warbler (285) was well below last year as well as below average.


The accompanying Excel spreadsheet has a page comparing the 2024 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 2025 on Saturday, 10 May.  

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