Blue whales switch to daytime singing before migrating — ScienceDaily

0 Comments

The blue whale is the largest animal on Earth. It’s also among the loudest.

“Sound is a vital mode of communication in the ocean environment, especially over long distances,” said William Oestreich, a graduate student in biology at Stanford University’s Hopkins Marine Station. “Light, or any sort of visual cue, is often not as effective in the ocean as it is on land. So many marine organisms use sound for a variety of purposes, including communicating and targeting food through echolocation.”

Although whale songs have been studied for decades, researchers have had limited success in deciphering their meaning. Now, by recording both individual whales and their greater populations in the Northeast Pacific, researchers from Stanford and the Monterey Bay Aquarium Research Institute (MBARI) have identified patterns in the trills and bellows of blue whales that indicate when the animals are migrating from their feeding grounds off the North American coast to their breeding grounds off Central America. Their research was published Oct. 1 in Current Biology.

“We decided to compare daytime and nighttime song patterns from month to month, and there, in the divergence and convergence of two lines, was this beautiful signal that neither of us really expected,” said John Ryan, a biological oceanographer at MBARI and senior author of the paper. “As soon as that image popped up on the screen, Will and I were both like, ‘Hello, behavior.'”

Further analysis across the five years of hydrophone recordings could reveal new information about blue whale migration, a 4,000-mile journey that ranks among the longest in the world — and which the creatures repeat every year. Despite the immensity of blue whales and their travels, scientists know very little about their behaviors, such as how they are responding to changes in the ecosystem and food supply from year

The Pandemic Shutdown in San Francisco Had Sparrows Singing Sexier Tunes | Science

0 Comments

Elizabeth Derryberry has been studying the songs of white-crowned sparrows for over a decade. Her 2012 work recording and analyzing birdsongs helped demonstrate that San Francisco sparrows slowly shifted their songs to a higher register to be heard above the hustle-and-bustle of city life. In March of this year, when shutdown measures in response to the COVID-19 pandemic rendered the city’s once-busy streets nearly silent, Derryberry was struck with an idea.

“It wasn’t until I was looking at some photos of actually the Golden Gate Bridge, I was like, ‘Oh my goodness. There really is a lot less traffic,’” says Derryberry. She wondered if the city’s sparrows—the same ones adapted to sing through the drone of city sounds—were shifting their songs. Derryberry hypothesized that without the onslaught of low-frequency sounds characteristic of urban life, the sparrows would drop their volume and pitch. In new study published this week in Science, she demonstrated just that.

“It’s like a cocktail party,” says Derryberry. “When it gets louder and louder in the room, you get louder and louder. Then when the party ends, you don’t keep shouting all night.”

To find out if and how the sparrows’ songs had changed, Derryberry and her colleagues looked at two sets of recordings: the first, from the spring of 2015; the second, from the spring of this year after shelter-at-home mandates. The recordings were taken in the same places, included locations in urban San Francisco and surrounding rural areas of Marin county.

When Derryberry’s team compared the recordings, they discovered that in spring 2020 city sparrows made a dramatic shift to lower, quieter song, while in 2015 the songs stayed high and loud. Rural birds in 2020 sang lower songs too, though their changes weren’t as dramatic as those of the city sparrows. As a