They are! Like chickens, for example – some chickens are born both male and female. This isn’t so weird in and of itself – it happens in pretty much all species, to one extent or another. But in chickens, it can manifest in particularly impressive fashion, in which the animal is born sexually bisected – a hen on one side, a rooster on the other. Researchers at the Roslin Institute in Edinburgh recently delved into this phenomenon, which once caused chickens like this to be burned at the stake because they were unclean products of dark magic, rather than being deep fried because they are delicious, as is right and proper. It appears that these gynadromorphous chickens (and other birds, such as finches and parrots) manifest as male and female at once because their individual cells are both Glenn and Glenda – rather than a makeup of cells that are all male or all female, the birds appear to have cell which are distinctly both, resulting in physical traits that split them down the middle, sexually.
Meanwhile, birds in the United States are responding to climate change in the only reasonable way–by shrinking. A study published in the journal Oikos had found that the majority of migrating birds US has gotten measurably smaller over the past few decades. It’s a finding that dovetails with findings last year that saw birds throughout Australia getting smaller and smaller over time, with many scientists finding the explanation for this in Bergmann’s Law, which states that, for reasons we don’t quite understand, fauna tends to be smaller in warmer climates, and as parts of the earth grow warmer, their birds will adapt to thrive in these new conditions, becoming as compact as they need to be to do so.