DOI: 10.5061/dryad.dv41ns26k
title: Harbour porpoises are flexible predators displaying context dependent foraging behaviours

description: Opportunistic mobile predators can adapt their behaviour to specific
 foraging scenarios, allowing them to target diverse prey resources. An
 interesting example is the harbour porpoise (Phocoena phocoena), a marine
 mammal with a huge energy demand feeding on a large variety of fish, squid
 and shrimps. Little is known about the foraging behaviour of harbour
 porpoises, as observations of wild specimens are notoriously difficult to
 obtain. In this study, foraging was identified in almost 60% of videos
 from UAV recordings in Danish coastal waters during daylight hours.
 Observations reveal them to be flexible predators, foraging on both single
 fish and schools of fish, as well as individually and in groups of varying
 size. We argue that some of the observed behavioural adaptations and
 context-dependent strategies for prey capture are based on information
 transfer and social learning. Our results provide unprecedented insights
 into the foraging behaviour of an opportunistic mammalian predator.
 Further, this study highlights the importance for porpoises to have access
 to coastal areas for energy acquisition, where they are in conflict with
 anthropogenic disturbances such as fisheries with the risk of by-catch.
description: **README for Data_Stedt_2024.xlsx and Video_supplement_Stedt_2024.mp4**
 This readme file was generated on 2024-06-19 by Johanna Stedt Last updated
 2024-11-26 **Data_Stedt_2024.xlsx** Extracted data from UAV recordings of
 harbour porpoises   **Video_supplement_Stedt_2024.mp4** Video examples of
 the observed behaviours and foraging techniques described in Stedt et al.
 (2024) Dataset and video file accompanies the paper Stedt J., Hamel H.,
 Torres Ortiz S., Højer Kristensen J. & Wahlberg M. (2024) Harbour
 porpoises are flexible predators displaying context dependent foraging
 behaviours. Ecology and Evolution. **GENERAL INFORMATION**
 Author/Principal Investigator Information Name: Johanna Stedt ORCID:
 0000-0002-0994-9023 Institution: Lund University Address: Department of
 Biology, SE-223 62 Lund, Sweden Email:
 [johanna.stedt@biol.lu.se](mailto:johanna.stedt@biol.lu.se) Period of data
 collection: September 2015 to September 2023 Method of data collection:
 quadcopter UAVs from the DJI Phantom and Mavic Series (models DJI 3, DJI 4
 Pro 2.0 and Mavic III Classic) Geographic location of data collection:
 coastal waters around Funen, Denmark   **SHARING/ACCESS INFORMATION** Data
 and code published under Creative Commons Zero waiver
 ([http://creativecommons.org/about/cc0](http://creativecommons.org/about/cc0)). If you use any part of these data or code, please acknowledge the primary authors using the recommended citation given below. Recommended citation for this dataset and video supplement: Stedt et al., (2024) Harbour porpoises are flexible predators displaying context dependent foraging behaviours, Dryad, Dataset/Video supplement, [https://doi.org/10.5061/dryad.dv41ns26k](https://doi.org/10.5061/dryad.dv41ns26k) **METHODOLOGICAL INFORMATION** UAV raw output files were processed as described in the paper to produce the data file Data_Stedt_2024.xlsx. Short representative sequences of observed behaviours and foraging techniques described in Stedt et al. (In press) were selected from raw UAV output files and combined into the video file Video_supplement_Stedt_2024.mp4 using iMovie. **DATA-SPECIFIC INFORMATION FOR: Data_Stedt_2024.xlsx** This file contains the complete extracted dataset of UAV sequences with harbour porpoises visible &gt;20 seconds. The data have been processed in preparation for analysis as described in the paper. The file Data_Stedt_2024.xlsx contains two data sheets: Non-foraging and Foraging. **SHEET-SPECIFIC INFORMATION FOR: Non-foraging** Number of variables: 6 Number of cases/rows: 227 Variable List: ID: Individual identification number Date: Date as YYYY-MM-DD. Location: Geographic location for UAV recording NrHP: Max number of observed individual harbour porpoises in the sequence Calves: Max number of observed individual harbour porpoise calves in the sequence Depth: Depth category (shallow/deep/shallow + deep, shallow: 0-5m, deep: &gt;5m) **SHEET-SPECIFIC INFORMATION FOR: Foraging** Number of variables: 15 Number of cases/rows: 314 Variable List: ID: Individual identification number Date: Date as YYYY-MM-DD. Location: Geographic location for UAV recording NrHP: Max number of observed individual harbour porpoises in the sequence Calves: Max number of observed individual harbour porpoise calves in the sequence Depth: Depth category (shallow/deep/shallow + deep, shallow: 0-5m, deep: &gt;5m) PreyVis: Prey visibility (1/0, 1=yes, 0=no) PreyType: Observed prey type (single/school/single + school/na, na = prey not visible) Cruise: Foraging mode *cruise search* observed (1/0, 1=yes, 0=no) Bottom: Foraging mode *bottom search* observed (1/0, 1=yes, 0=no) Split: Foraging mode *split* observed (1/0, 1=yes, 0=no) Chase: Foraging mode *chase* observed (1/0, 1=yes, 0=no) Turn: Foraging mode *turn* observed (1/0, 1=yes, 0=no) Herd: Foraging mode *herd* observed (1/0, 1=yes, 0=no) Catch: Foraging mode *catch* observed (1/0, 1=yes, 0=no)