Information use in foraging flocks of songbirds: no evidence for social transmission of patch quality

Abstract

Animals use behavioural cues from others to make decisions in a variety of contexts. There is growing evidence, from a range of taxa, that information about the locations of food patches can spread through a population via social connections. However, it is not known whether information about the quality of potential food sources transmits similarly. We studied foraging behaviour in a population of wild songbirds with known social associations, and tested whether flock members use social information about the profitability of patches to inform their foraging decisions. We provided artificial patches (ephemeral bird feeders) that appeared identical but were either profitable (contained food) or unprofitable (contained no food). If information about patch profitability spreads via social associations, we predicted that empty feeders would only be sampled by individuals that are less connected to each other than expected by chance. In contrast, we found that individuals recorded at empty feeders were more closely associated with each other than predicted by a null model simulating random arrival of individuals, mirroring pattern of increased connectedness among individuals recorded at full feeders. We then simulated arrival under network-based diffusion of information, and demonstrate that the observed pattern at both full and empty feeders matches predictions derived from this post-hoc model. Our results suggest that foraging songbirds only use social cues about the location of potential food sources, but not their profitability. These findings agree with the hypothesis that individuals balance the relative economic costs of using different information, where the costs of personally sampling a patch upon arrival is low relative to the cost of searching for patches. This study extends previous work on information spread through animal social networks, by suggesting important links between how individuals use information at different stages of the acquisition process and the emerging population-level patterns of patch use.

Social network position predicts male mating success in a small passerine

“…We inferred the social position of individuals by creating a network based on the foraging associations of PIT-tagged birds at feeders. While information about the social behavior of birds is restricted to a foraging context at artificial feeders and thus may not represent their natural association patterns, previous work on tits (Paridae) has demonstrated that foraging associations are meaningful in predicting processes in other contexts such as the discovery of novel food patches ( Aplin et al 2012 ; Hillemann et al 2020 ), the spatial breeding arrangement ( Firth and Sheldon 2016 ; Beck et al 2020 ) and mating patterns ( Beck et al 2020 ). We used data from the two months before the start of breeding (from 1 February until 13 March 2018) to create a social network.…”

Food discovery is associated with different reliance on social learning and lower cognitive flexibility across environments in a food-caching bird

“…all individuals that had previously arrived at the patch). Following Hillemann et al [47], we compared these observed patterns to a null model which simulated individuals arriving at the feeder in random order, generated by randomly selecting k individuals from the local network. This null model assumes social learning plays no role in feeder discovery.…”

Opposite-sex associations are linked with annual fitness, but sociality is stable over lifetime

“…Thus, sociality can only evolve where the benefits outweigh the costs (Krause and Ruxton 2002; Silk 2007; Silk et al 2014). For example, communal foraging during the non-breeding period can facilitate information transfer between individuals (Aplin et al 2012; Hillemann et al 2020) and reduce predation risk (Cresswell and Quinn 2011). But during the breeding season these benefits also incur costs associated with competition for resources, mates (Le Galliard et al 2005; Grant and Grant 2019; Kurvers 2020; but also see Lea et al 2010) and offspring paternity (Birkhead and Biggins 1987; Forstmeier et al 2011; Mayer and Pasinelli 2013).…”