Are animal gradually change the frequency of their calls in response to urban noise?

Lombard effect (described by Etienne Lombard in 1911) has been used to describe an increase in amplitude of a call or vocalization. When you come home from a loud party you usually have a sore throat from yelling all night. The Lombard effect has been observed in zebra finches, Japanese quail, blue-throated hummingbirds, the common […]

Lombard effect (described by Etienne Lombard in 1911) has been used to describe an increase in amplitude of a call or vocalization. When you come home from a loud party you usually have a sore throat from yelling all night. The Lombard effect has been observed in zebra finches, Japanese quail, blue-throated hummingbirds, the common marmoset, beluga whales, orcas, manatees, humans and many other species.

However, Lombard effect is only really useful for getting over short-term noisiness. With development of technology and industry the noise never seizes.

To get around yelling all the time, or calling longer, some animals gradually change the frequency of their calls. The North Atlantic right whale, for example usually sends its signals at low frequencies, from 40-400Hz. That’s the same region effected by shipping noise. (Try hearing the right whale’s characteristic up-call through all the traffic). So to get around it, the whales first increased the amplitude of its call to keep in touch with other whales during loud periods. Eventually though, the whales started calling at higher frequencies, to escape the shipping noise.

Read more here.