Nearly 3.8 million birds crossed through Maricopa County overnight, according to Phoenix Mayor Kate Gallego, who called it the peak of fall migration as birds head south for the winter. The eye-popping figure landed just as the city rolled out a new campaign aimed at making Phoenix safer for the birds passing overhead.
Gallego shared the number in a post on X, writing, “A stunning number of nearly 3.8 million birds crossed through Maricopa County last night—the peak of migration season as they fly south for the winter.” The mayor's post, found at her account on X
, also announced that Phoenix had teamed up with Audubon Southwest this week to launch a new initiative called Bird-Friendly PHX.
The timing lines up with the formal kickoff of that campaign, which the city and Audubon Southwest held Tuesday, Sept. 29, at the Nina Mason Pulliam Rio Salado Audubon Center, according to the Daily Independent. The free public event ran from 5 to 7 p.m., giving residents a chance to learn about the new push before the flood of migrating birds Gallego described just days later.
Why Phoenix Sits in the Flight Path
Phoenix lies along the Pacific Flyway, a migration corridor stretching from Alaska into South America that carries millions of birds each year, per the same report. That geography helps explain why a single overnight count in Maricopa County could run into the millions, even as the mayor's office framed it as the seasonal high point.
Bird-Friendly PHX focuses specifically on hazards tied to urban growth, including reflective or transparent windows and artificial nighttime lighting that can disorient migrating birds and raise collision risks, the outlet reported. The campaign also encourages residents to plant native species that offer food and shelter for birds passing through.
As part of the rollout, residents were invited to take the Bird-Friendly PHX pledge and pick up practical tips for their own homes — turning off unnecessary lights, closing curtains and blinds at night, and making windows more visible to birds in flight, the Daily Independent noted.
Putting the Number in Context
The scale of overnight bird movement isn't unique to Phoenix. A broader study using weather radar data to track migration stopovers nationwide found that 48 percent of U.S. bird-migration hotspots show up in metropolitan areas during spring, and 44 percent in fall, according to Audubon. That research also found more urban migration hotspots in the western United States than in the East, with Phoenix named alongside Los Angeles and San Diego as a dry Western city where higher-income neighborhoods tend to host more birds, likely tied to extra water and vegetation.
The stakes behind campaigns like Bird-Friendly PHX are real: Audubon reports more than one billion birds die from window collisions across the country each year, with the toll rising especially during migration. That backdrop gives the city's push for darker nights and more visible glass added weight beyond a single dramatic count.
Not every number tells the full story on its own, though. BirdCast, which tracks migration activity nationally, cautions that its totals are estimates rather than direct counts, noting that the number of birds in flight may occasionally be greater than the number that actually passed through a given area. BirdCast's live migration tracking runs from August 1 through November 15 each fall, comparing current activity against historical data spanning 2013 through 2021.
A Decade-Plus of Bird-Friendly Efforts
Phoenix's bird-safety push isn't entirely new. The city was designated an Urban Bird Treaty City back in 2011, after Audubon Southwest received a U.S. Fish and Wildlife Service Challenge Grant, according to the federal agency's Rio Reimagined Urban Bird Coalition page. Bird-Friendly PHX builds on that history, aiming to make the city a more welcoming place for both migrating birds and the residents who share their neighborhoods with them.
