Abstract
Just like how people have different languages, bird species have their own songs. These songs help birds recognize each other and find mates. Two factors may shape birdsong evolution: the habitat a bird lives in and a bird’s physical features. First, habitat affects how far songs can travel. Second, body size and beak shape can limit the types of sounds a bird produces. We explored how these factors influence song evolution in a group of birds called honeyeaters. Body size is the most important factor explaining differences in song. We found that larger birds produce lower-frequency songs, just like how larger humans have deeper voices! Some findings suggest habitat influences song evolution too. However, this is likely because of differences in body size between different habitats. These results are important because birds are expected to get smaller with future climate change, and this could alter how birds communicate!