Olive-sided flycatchers are a threatened species. The last count — in 2013 — was only 900,000. (Photo: Emily Upham-Mills)
According to Upham-Mills, to monitor live or with a camera would be time consuming and expensive, and wouldn’t result in the desired data.
“Not only is locating a nest and confirming its contents difficult and time consuming, but it could never be done on a landscape scale to inform broader questions around habitat quality.”
Applying results to other species
Upham-Mills says the theory underpinning her song research is that all animals vocalize for a reason.
“When we know that reason and the resulting pattern, we can use this to eavesdrop on them and know something about them,” she says. “In the case of songbirds, they typically sing to attract a mate and defend a territory. Because of that, they sing more when single and less after they have paired since they no longer need to invest energy in finding a mate.”
Data gathered showed that the birds sing even less after nestlings have hatched, so they don’t draw attention to the nest. However, a single male will keep singing at a high rate because he’s still trying to attract a female.
The same processes can be seen in animals like monkeys, whales and frogs, who all call or sing for known specific reasons.
“Our hope with this research is that we have found a modelling approach that can be tweaked according to the species and the question to make accurate predictions about their state based on measurable information in the sounds they make,” says Upham-Mills.