Data from: Vocal signatures affected by population identity and environmental sound levels

Passive acoustic monitoring has improved our understanding of vocalizing
organisms in remote habitats and during all weather conditions. Many
vocally active species are highly mobile, and their populations overlap.
However, distinct vocalizations allow the tracking and discrimination of
individuals or populations. Using signature whistles, the individually
distinct calls of bottlenose dolphins, we calculated a minimum abundance
of individuals, characterized and compared signature whistles from five
locations, and determined reoccurrences of individuals throughout the
Mid-Atlantic Bight and Chesapeake Bay, USA. We identified 1,888 signature
whistles in which the duration, number of extrema, start, end, and minimum
frequencies of signature whistles varied significantly by site. All
characteristics of signature whistles were deemed important for
determining from which site the whistle originated and due to the distinct
signature whistle characteristics and lack of spatial mixing of the
dolphins detected at the Offshore site, we suspect that these dolphins are
of a different population than those at the Coastal and Bay sites.
Signature whistles were also found to be shorter when sound levels were
higher. Using only the passively recorded vocalizations of this marine top
predator, we obtained information about its population and how it is
affected by ambient sound levels, which will increase as offshore wind
energy is developed. In this rapidly developing area, these calls offer
critical management insights for this protected species.