Beyond the information centre hypothesis: communal roosting for information on food, predators, travel companions and mates?

Abstract

Communal roosting – the grouping of more than two individuals resting together – is common among animals, notably birds. The main functions of this complicated social behaviour are thought to be reduced costs of predation and thermoregulation, and increased foraging efficiency. One specific hypothesis is the information centre hypothesis (ICH) which states that roosts act as information centres where individuals actively advertise and share foraging information such as the location of patchily distributed foods. Empirical studies in corvids have demonstrated behaviours consistent with the predictions of the ICH, but some of the assumptions in its original formulation have made its wide acceptance problematic. Here we propose to generalise the ICH in two ways: (1) dropping the assumption that information transfer must be active, and (2) adding the possibilities of information exchange on, for example, predation risk, travel companions and potential mates. A conceptual model, inspired by shorebirds arriving at roosts after foraging on cryptic prey, is proposed to illustrate how testable predictions can be generated. The conceptual model illustrates how roost arrival timing may convey inadvertent information on intake rate, prey density, forager state (i.e. digestive processing capacity) and food quality. Such information could be used by naïve or unsuccessful foragers to select with whom to leave the roost at the subsequent foraging opportunity and thus increase foraging success. We suggest that inadvertent information transfer, rather than active information exchange, predominates in communal roosts.

Scaling up ideals to freedom: are densities of red knots across western Europe consistent with ideal free distribution?

“…Besides this form of personal information about their resource landscape, red knots have plenty of access to public information as they live in large groups at their wintering sites. For example, red knots may exchange information about the quality of feeding sites when at their roost during high tide [54]; also, knots can use the location of conspecifics on intertidal flats as an indicator of patch quality [15]. Furthermore, knots wintering in the Dutch Wadden Sea can easily fly to the Wash once or twice in a single winter, and thereby track the continuously changing quality of an estuary, as evidenced by the resightings of colour-ringed individuals [37].…”

From colony to first patch: Processes of prey searching and social information in Cape Gannets

“…The use of social information for locating food around a colony is highly controversial (Mock et al 1988, Richner and Heeb 1995, Bijleveld et al 2010 but is supported by theoretical and modeling studies (Waltz 1982, Valone 1989, Deygout et al 2010. In particular, game-theory models predict that using social information to find food is an evolutionarily stable strategy for colonial foragers Szép 1994, Barta and.…”

Communal roosting sites are potential ecological traps: experimental evidence in a Neotropical harvestman

“…Communal roosts are often traditional in that they are used primarily because they were used by conspecifics in the past, not because they are necessarily more suitable than alternative sites (reviewed in Grether and Donaldson 2007). Some avian communal roosts have been used for well over a century (Bijleveld et al 2010). Species that form communal roosts may be especially prone to ecological traps, for two reasons.…”

“…Communal roosting is a taxonomically widespread behavior in which animals regularly congregate at specific locations (Bijleveld et al 2010). Communal roosts are often traditional in that they are used primarily because they were used by conspecifics in the past, not because they are necessarily more suitable than alternative sites (reviewed in Grether and Donaldson 2007).…”