Billion Birds Migrate to Yucatán; Poaching Threatens Trip

Mérida, Mexico — Each autumn, the sky becomes an aerial highway for millions of birds fleeing the cold in the United States and Canada. This year, 2025, was no exception: according to the Cornell Lab of Ornithology, the so-called Night of the Billion Birds reached a new record on September 25, when over 1.2 billion specimens took flight towards the south.

In the Yucatán Peninsula, this natural spectacle announces the arrival of emblematic species such as the painted bunting –known in Mayan as Chéel yi’ijil–, the indigo bunting (Ch’oj yi’ijil), the blue grosbeak (Piim kooj yi’ijil), and the rose-breasted grosbeak (Chak tseem), reported Pierre Medina Arjona, director of the Proyecto Santa María.

The monitoring of this migration is carried out by BirdCast, a system that uses more than 160 weather radars in the United States to record the nocturnal movement of birds. Only once before, in 2023, had a figure exceeding one billion specimens in a single night been documented.

The journey, however, is full of threats. In the United States, environmental organizations are calling for lights in buildings and homes to be turned off to prevent birds from becoming disoriented during their nocturnal flight. They also recommend placing decals on windows to reduce fatal collisions with glass.

In Mexico, and particularly in Yucatán, the main threat is not lights, but the traps set by poachers known as "boca trampa," which put the survival of these species at risk, despite being protected by the Ley General de Vida Silvestre, the Convención Internacional entre Estados Unidos y México para la Protección de las Aves Migratorias, and the Norma Oficial Mexicana NOM-059-SEMARNAT-2010.

“We need to reinforce surveillance and community awareness. Every migrating bird plays a vital role in the balance of ecosystems,” emphasized Medina Arjona.

With the arrival of autumn, the call from specialists and organizations is clear: to ensure a safe sky for migratory birds and to stop the illegal hunting that threatens their passage through Yucatán.