Visual trail following in colonial seabirds: theory, simulation, and remote observations

Abstract

Seabirds have long been thought to exploit social information when searching for their prey, the distribution of which is often patchy and variable. The fact that most seabirds breed colonially has led to speculation that colonies serve as “information centers,” allowing their inhabitants to learn about the distribution of food by observing or following other successful foragers, though this hypothesis is controversial and the evidence for it is mixed. However, several recent studies have documented behaviors that suggest some seabirds do exploit social orientation cues at or near their colonies in order to orient toward food. In this paper, I explore in‐depth one such social orientation behavior, which I call “visual trail following.” I derived a simple model of information transfer and showed that trail following should be favored over other commonly hypothesized foraging behaviors. An individual‐based simulation model was then used to test this theoretical prediction against several other foraging strategies while varying prey patchiness and colony size. The model's results showed that trail following was the optimal strategy across a wide range of conditions. Finally, I used radar data recorded at a tern colony in coastal New York to demonstrate evidence for trail following in the movements of wild seabirds. These results show that trail following and similar behaviors are effective foraging strategies that are likely important for seabirds and other colonial animals.

When are bacteria really gazelles? Comparing patchy ecologies with dimensionless numbers

“…Finally, the low Lessard number (Le = 0.005) indicates that terns rarely deplete patches, so models of this interaction can treat the density and distribution of their prey as endogenous variables (cf. Urmy, 2021).…”

The Cognitive Ecology of Animal Movement: Evidence From Birds and Mammals

“…Another possibility is that individuals from the aggregation follow departing, apparently informed individuals to food patches. Some field observations agree with this possibility while others do not (Brown, 1986;Mock et al, 1988;Marzluff et al, 1996;Danchin and Richner, 2001;Sonerud et al, 2001;Harel et al, 2017;Urmy, 2021). It is fair to assume, however, that socially biased movement occurs in many species.…”

Individual consistency in the localised foraging behaviour of shy albatross (Thalassarche cauta)

“…The similarity of foraging decisions between individuals can indicate population‐level sensitivity to climate change. Individuals making similar decisions or following social cues may be able to share beneficial foraging information and navigational cues (Urmy, 2021); however, a potential disadvantage could be an increase in competition for resources (Sherley et al., 2017). Alternatively, a population consisting of similarly specialised individuals could indicate strong environmental or biological constraints (Ceia & Ramos, 2015).…”

“…Foraging behaviour plays a key role in determining niche use (Carneiro et al., 2017) and characterising a species' sensitivity to climate change. Foraging decisions may be driven by environmental (Bost et al., 2015; Horswill et al., 2017), social (Urmy, 2021), or individual (Patrick & Weimerskirch, 2014; Votier et al., 2017) cues and constraints and may change with age (Patrick et al., 2020; Votier et al., 2017). Spatially, an individual may consistently forage in a preferred area which could increase local knowledge and experience, leading to increased foraging efficiency (Arthur et al., 2015; Call et al., 2008; Patrick & Weimerskirch, 2014).…”