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bioRxiv · 10.1101/2025.09.19.676425

A fish finder for birds: route-dependent foraging behavior of the brown booby (Sula leucogaster) on a passenger ferry

Hayashi, R.
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Abstract

This manuscript reports a novel case of route-dependent foraging behavior in the brown booby (Sula leucogaster), based on visual observations from a passenger ferry between Chichijima and Hahajima Islands, Ogasawara, Japan. On four dates in 2017, the number of accompanying boobies and their plunge-diving behavior were recorded using only handheld counters. More birds and dives were observed on routes departing from the nesting-rich Hahajima, with peak activity mid-route. These findings suggest that the ferry acts as a "fish finder," flushing prey such as flying fish for the birds to exploit. The study highlights how low-tech observations from public transport can provide valuable behavioral insights and underscores the potential of citizen science in seabird ecology.

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Hayashi, R.. 2025-09-21. A fish finder for birds: route-dependent foraging behavior of the brown booby (Sula leucogaster) on a passenger ferry. https://doi.org/10.1101/2025.09.19.676425

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