The earth is warming due to climate change, and both people and animals are having to find ways to adapt.
Like how you might have to start wearing summer clothes earlier, or apply sunscreen regularly, songbirds, too, have developed behaviors that help them cope with extreme heat. Scientists call these heat dissipation behaviors. Like humans, in the heat, songbirds look for shady spots to rest, become less active, and even pant. Might these activities have an effect on their signature songs?
To test this, scientists put zebra finches in a heated container and recorded their songs after being exposed to heat. They found that the zebra finches exposed to high heat did sing less overall. But there’s even more to the zebra finch’s heat-induced change of tune: like when you’re out of breath and it becomes difficult to get long sentences out, the birds exposed to heat also sang songs with much shorter syllables.
You might not think about it when you wake up to hear a beautiful chorus of birdsong in the morning, but these songs are most often sung by males in order to attract female mates. This opens up a bunch of other questions about the effect of heat on songbird behavior: Given that the male bird’s song changes when living in high heat, does this change have an effect on the ways females respond to song? Can those females tell the difference between a song produced in the cold, versus one produced in heat? And do they prefer one type of song over the other?
The same scientists who found that male zebra finch’s songs changed in the heat also tested this question. They found that the female birds could distinguish between high and low-temperature songs using the song syllable length, with longer syllables generally associated with cool-temperature songs and shorter syllables associated with hot-temperature songs. They also found that the female birds did show a preference for one type of song: they preferred songs with longer syllables.
Climate change is affecting everything on earth, and this research is just another example of this. It shows us that, as long as we want to keep waking up to a morning symphony of birdsong, we’ll have to do our best to stop further warning.
C.M. Coomes, E.P. Derryberry. October 2021. High temperatures reduce song production and alter signal salience in songbirds. Animal Behaviour. 180: 13-22.
https://doi.org/10.1016/j.anbehav.2021.07.020
