It turns out a lot of big whales have a taste for the Big Apple area, including the 100-foot (30-meter) blue whale, the largest animal on Earth, scientists say.

A network of ten underwater sound recorders in place off the length of the south coast of Long Island and throughout New York Harbor (map) between 2008 and 2009 detected a surprising density of ocean giants across an unexpectedly vast area, experts say.

These "open mikes" picked up the ballads of the fin whale, blue whale, humpback whale, minke whale, sei whale, and the rare North Atlantic right whale, said Christopher Clark, Bioacoustics Research Program at the Cornell Lab of Ornithology in Ithaca, New York.

The fin, humpback, right, and sei whales are on the U.S. endangered species list, meaning the federal government considers them to be "on the brink of extinction."

But what amazed the team the most was not the types of whales heard, but the sheer density of animals spread out over the entire study area, said Aaron Rice, science director of the bioacoustics lab.

For one thing, the scientists were struck by the "juxtaposition of having such large charismatic animals that represent ocean biodiversity living right off of the largest city on the Atlantic coast," Rice said

Some of the whales cruised as close as 10 miles (16 kilometers) from New York City, he said.

Clark said, "If you were standing at the top of the Statue of Liberty and looked south or southeast, if you [could see] under the water, there were whales singing under the surface."

In some cases, it was the whales' distance both near and far from shore that surprised the researchers.

For instance, the recorders picked up songs of the North Atlantic right whale 70 miles (113 kilometers) from shore—where the coastal dweller isn't thought to venture.

The acoustic technology, however, does not yet allow the scientists to accurately estimate exactly how many whales they heard.

Science director Rice said, "Now that we know they are there, our next question is how many."

Motormouth Whales

Whales communicate mostly by sound, and each whale species has a distinct call, Rice said. This made it easy for scientists to identify which species had been recorded, he said.

Some of the whale species were migrating through New York on the way to feeding grounds farther north, while others tend to stick around the coast throughout the year, Rice said. Occasionally a whale will wander all the way into a harbor and attract media attention.

Overall, the acoustic monitoring is part of a larger project to understand what sorts of human-made sounds exist along the U.S. East Coast, and how these sounds may impact whales long-term, Rice said. (Related: "Killer Whales Strain to 'Talk' Over Ship Noise?")

Acoustic recording has proven a dependable technique for tracking the mammals—especially because "it's really hard for whales to keep their mouths shut," Clark quipped.