An Ethogram for Bottlenose Dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland

Abstract

Ethograms, or categorized lists of behavioral descriptors, are fundamental research tools in the study of animal behavior and are essential to the overall understanding of the behavioral ecology of a species. With specific definitions of activity state categories and behavioral event types, the behavior of a species can be described, quantified, and compared across populations. We present the first ethogram for bottlenose dolphins (Tursiops truncatus) in Ireland based on sighting records collected during 256 surveys (2014-2016) in the Shannon Estuary. The ethogram consists of 11 activity states and 45 behavioral events. The most frequently recorded activity state was Travel (52%), while the most frequently recorded behavioral events were Slow travel (40% of sightings), Surface rush (28% of sightings), and Leap (28% of sightings). The ten least frequently recorded behaviors were seen in only 10% of total sightings with < 8 records each. A video test for multiple researchers to assess inter-observer reliability in behavioral data recording demonstrated the validity of this study’s behavioral data and the efficacy of the ethogram in its applicability to other studies. Validity (percentage agreement = 88.1 ± 7.0) and reliability (Fleiss’ Kappa = 0.81) scores were high across 24 test participants (12 trained and 12 untrained), but results indicated that those with prior training scored significantly higher. Furthermore, we investigate the presence/absence of behaviors recorded in other studies of bottlenose dolphins. This ethogram and behavioral discussion serve to describe and compare quantita-tive data on the behavior of bottlenose dolphins in Ireland for the first time and provide a strong basis for further research.