A recent international study led by Universitat Autònoma de Barcelona reveals a significant decline in the average body mass of birds in Africa, Asia, and the Americas between 1940 and 2020, with reductions of up to 72%. The research highlights the collective memory of over 1,400 individuals, including indigenous populations, who recalled the bird species they predominantly observed in their childhoods. This information was contrasted with current data on avian populations in the regions studied.

The study, published in the journal Oryx, shows a consistent pattern across ten different locations around the world: the abundance of larger bird species has decreased while smaller species have become more common. This trend raises concerns about biodiversity and the ecological implications of such changes, suggesting that habitat alterations and climate change might play a significant role in these shifts.

As larger bird species dwindle, the implications for ecosystems are profound, as they often occupy key ecological roles. The findings could signal a broader environmental issue that echoes the ongoing challenges posed by human activity and climate variations across diverse habitats.