Published

Data from: Prey ingestion rates revealed by back-mounted accelerometers in Eurasian spoonbills Version 22

Royal Netherlands Institute for Sea Research https://doi.org/10.25850/nioz/7b.b.yd

Background Quantifying foraging success in space and time and among individuals is essential for answering many ecological questions and may guide conservation efforts. However, collecting this information is challenging for species that forage on mobile prey and are difficult to observe visually, for example, because they forage in inaccessible areas or at night. In such cases, the use of tracking devices that simultaneously collect location and acceleration data may provide a solution if foraging success can be extracted successfully. The aim of this study was to assess how well searching for and ingesting prey, among other behaviours, could be distinguished from 20 Hz acceleration data collected by GPS/ACC-trackers mounted on the back of Eurasian spoonbills Platalea leucorodia. Upon capturing a prey, spoonbills make a distinct movement with their head and back to throw the prey from the tip of the bill into the throat.

Methods We compared the behavioural classification performance of random forest models that were trained and tested on video-annotated acceleration data segments of different (fixed or flexible) lengths. The best-performing model was then applied to 4 years of data of spoonbills foraging in the Wadden Sea during the breeding season, to explore seasonal and annual variation in prey ingestion rates.

Results Highest classification accuracies (as indicated by the F-measure, a balanced measure of precision and sensitivity) of foraging behaviours were achieved by analysing short fixed-length segments (0.4-0.8 s) or 'flexibly-cut' segments. The F-measure was very high (> 0.90) for searching, standing, sitting and flying (distinguishing active and passive flight), 0.73 for ingesting prey and 0.65 for walking. False positive and negative prey ingestions were equally likely and most often confused with searching, resulting in a close match between the predicted and observed prey ingestion rates. Application of the best-performing model revealed strong seasonal patterns in prey ingestion rates in the Wadden Sea that varied between years.

Conclusions We show that prey ingestion rates of Eurasian spoonbills can be fairly accurately estimated from acceleration data. These results are promising for the use of spoonbills equipped with GPS/ACC-trackers as monitors of spatial and temporal variation in the availability of small fish and shrimp, which is key to understand their foraging and migratory movements of spoonbills and provides information on the quality of (coastal) wetlands.

Data and Resources

Additional Info

Field Value
Subject Earth and Environmental Sciences
DAS Code 7b.b.yd
Source https://dataportal.nioz.nl/doi/10.25850/nioz/7b.b.yd
Version 22
Creator(s)
Lok, Tamar (Royal Netherlands Institute for Sea Research)
ORCID
Contact the corresponding author
Depositor Tamar Lok
Publication Date 2023-01-30
Deposit Date 2023-01-12
Dataset Persistent Identifier DOI:10.25850/nioz/7b.b.yd
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Related identifier
Contributor NIOZ Royal Netherlands Institute for Sea Research
Distributor Research Data Management(NIOZ Royal Netherlands Institute for Sea Research)
Distribution Date 2023-01-12
Production Date 2023-01-30
Dates
Funding References
Waddenfonds (WF209925)
Metawad

Netherlands Organisation for Scientific Research (NWO) (016.Veni.192.245)
Veni grant Tamar Lok

Netherlands Organisation for Scientific Research (NWO) (Spinoza Premium 2014)
Spinoza Premium Theunis Piersma
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