True to its identify, the collared puffbird has a black band of feathers round its neck and an oddly bulbous head. The chook is, frankly, a little bit comical, however its scenario is just not: The common puffbird physique has decreased in mass by practically 4% since 1980, in accordance with the staff’s outcomes.

“The broad result is that climate is changing at our study site,” and “at the same time, the morphology of birds exposed to those conditions is changing,” stated Vitek Jirinec, an ecologist at Louisiana State University and lead creator of the examine, in an e mail to Gizmodo.

“Variation in mass, wing, and mass:wing is also linked to temperature and rainfall in the shorter-term (seasonal) interval,” Jirinec added. “That means more evidence that bird body size and shape is related to temperature and rainfall. If these change over time, it makes sense to see the morphological shifts we report. As for how exactly mass is related to climate, we are not sure.”

One hypothesis proposes that animal physique sizes get smaller when the climate will get hotter. Another is that local weather change has diminished the quantity of meals obtainable to those birds. In both case, it seems the local weather is driving the discount in chook mass, with the birds species on this examine dropping about 2% of their physique mass per decade on common.