Mockingbirds change their tune with changing climate

Why are some birds simple singers and others vocal virtuosos?

Two studies link superior singing skills to higher intelligence that enables birds to survive today's harsher and inconsistent climate.

Male Northern Mockingbird in song

Researchers at the National Evolutionary Synthesis Center at the Cornell Lab of Ornithology in Ithaca, New York, and McGill University in Montreal focused their work on Northern Mockingbirds, a species known for its ability to express complex songs. Mockingbirds even mimic the songs of other birds, hence their name. 

Their study looked a large population of mockingbirds in diverse habitats. They found that species in more variable climates sing more complex tunes.

The researchers hypothesized that as today's environment becomes more unpredictable, song displays become more elaborate. They attribute this to the birds' survival and reproduction instincts. The birds don't know when food will be available or how long it will be around. The consequences of selecting a mediocre mate are magnified when the weather is inconsistent.

Male mockingbirds sing primarily to impress mates. Superior singing skills are a cue to the female that a male is a good catch. Males that sing more complex songs tend to carry fewer parasites and have offspring that are more likely to survive.

At the University of North Carolina, researchers suspect that song-learning ability may also be a display of learning ability in general. Complex songs may indicate which males have not only brawn but also brainpower.

In addition, singing skills may be a sign that males are clever enough to cope with unpredictable environments. Individual birds that are more intelligent tend to be better able to compensate for the difficulties of unpredictable situations, such as harsh weather.

"For example," the North Carolina researchers said, "if some individuals are able to invent new foraging techniques, then they are going to be better at surviving harsh winters than the poor guy who only knows one way to forage. The more intelligent you are, the more resourceful you are."

Does this pattern hold for other bird species? Ultimately additional research may shed light on that question.