You probably heard a songbird this morning — maybe a bright-vested robin or a purple martin calling from the yard.

But the seasonal symphony isn't what it used to be. The singers are exiting the stage in droves.

"By some estimates, we may have lost almost half the songbirds that filled the skies almost 40 years ago," ornithologist Bridget Stutchbury told the CBC.

We know that noise pollution is a significant factor. A study published earlier this year suggested the constant drone from oil and gas operations and blaring city sounds are stressing songbirds — ultimately dampening their nesting instinct.

Songbird on roof of car Songbirds may be getting too stressed to sing — or nest — in loud, urban environments. (Photo: Cora Mueller/Shutterstock)

That's on top of the usual culprits: habitat encroachment, agricultural development and all the pesticides that accompany it. No wonder today's birds are singing a sad, sad song.

The purple martin alone, according to the North American Breeding Bird Survey, has lost around 78 percent of its population since 1970.

That staggering decline is a big reason why researchers are are scrambling to track songbird migration patterns. The trouble is, songbirds, so dramatic in announcing themselves to the world, have a curious tendency to slink off the quietly at the end of the show.

How we can learn more

Up until recently, scientists have only been able to draw general maps of their winter interludes.

But last year, a team led by Stutchbury fitted 20 purple martins with tiny devices that sense ambient light to calculate a bird's precise latitude and longitude. Because they don't transmit data, the ultra-light geolocators have to be collected when the bird returns.

Fortunately, some of those birds have been coming back — and they're painting a rich picture of the secret lives of songbirds.

"We've seen birds that have travelled from Pennsylvania to the Gulf Coast in only two days," Stutchbury tells the CBC. That's more that 800 miles. And farther and faster than researchers had ever realized.

The data from geolocators also points to a much broader menace. "Climate change is a new threat for songbirds," Stutchbury notes.

While purple martins, like other songbirds, bide their winters in southern climes, they wing back to their nesting grounds in spring. The trouble is, they may not be adjusting to the fact that spring is arriving earlier every year. As a result, they're showing up late and missing out on the spring harvest.

Baby purple martins poking their heads from birdhouse Purple martins have seen their numbers decline by 78 percent since 1970. (Photo: Jean Faucett/Shutterstock)

Where do they go?

Songbirds, however, are still holding tight to one crucial piece of the puzzle. We don't know where they go to die. Tagged birds that don't come back from winter migration take their secrets to the grave.

"If we can't figure out where they die, then we can't figure out why they're dying, and we can't then implement conservation strategies to stop those declines," Pete Marra of the Smithsonian Institute's Migratory Bird Center, told The Atlantic.

Until, at least, ICARUS comes online. Short for International Cooperation for Animal Research Using Space, the initiative involves mounting an antenna on the International Space Station. Birds tagged with tiny solar-powered trackers would spend their entire lives under the unflinching eye of ICARUS. In turn, the system would offer scientists valuable data not only on every flap of songbird's wing — but also where and how that bird died.

Tracking device for ICARUS Inititiative These tiny solar-powered devices will beam detailed data about an animal's life and death to the space station. (Photo: Snapshot from YouTube/MaxPlanckSociety)

But ICARUS, which is scheduled to launch in August, has even grander ambitions. The technology will not only track the entire lives of birds, but also survey the lives of animals as small as honeybees.

For humans, ICARUS could also keep an eye on the food chain, even helping track the spread of epidemics like Ebola and avian flu. By tracking wildlife, we may also gain valuable insight into natural disasters.

"There's good scientific data showing that animals can anticipate earthquakes, volcanic eruptions, and tsunamis," project leader Martin Wikelski told IEE Spectrum.

The project is being hailed as the "internet of animals". Or, depending on how you look at it, mass surveillance for wildlife. But in the case of the fast-disappearing songbird — so vital to plant life and ecosystems on this planet — it may be music to our ears indeed.

You can learn more about the Icarus project in the video below:

Where do songbirds go when the music's over?
A new eye in the sky could finally solve the mystery of songbird deaths.