Social learning and the significance of mixed-species flocks of chickadees (Parus spp.)

Abstract

The experiments described in this paper show that two species of chickadees learn from one another about the location and nature of potential feeding places when they are foraging together in mixed flocks in large aviaries. In the first experiment, I show that when an individual of one species finds a single food item, members of the other species modify their foraging behavior over the next few seconds so that they put more effort into searching near the site of the find. This applies to both species. Further, members of both species modify their foraging behavior when a bird of the other species searches in a place unsuccessfully. This response to an unsuccessful search is similar to, but weaker than, the response to a food find. The second experiment shows that when the two species are trained to forage in different positions in the experimental trees, they converge in their foraging behavior when they are put in mixed flocks, This is a result of copying. The third experiment shows that individuals of both species are more likely to discover a completely new foraging place if they are in the presence of an experienced bird of the other species.I discuss these results in relation to theories on the adaptive significance of flocking, and conclude that learning about potential feeding places from other species is an important function of mixed flocks, at least for some species. This does not exclude the possibility of other functions of mixed flocks.

Positive Relationships between Association Strength and Phenotypic Similarity Characterize the Assembly of Mixed-Species Bird Flocks Worldwide

“…Species associations within each matrix are therefore unlikely to have been caused by broad-scale habitat filtering. Given the spatial proximity and interaction potential of flock members (Graves and Gotelli 1993) and the behavioral evidence for positive interactions in flocks (e.g., Krebs 1973;Goodale and Kotagama 2005;Satischandra et al 2007), we believe that many of these associations likely reflect direct interactions between species. Nevertheless, it is possible that fine-scale microhabitat selection, which we did not measure in our study, might also play a role in producing some of the species-association patterns reported here (Graves and Gotelli 1993).…”

“…Support for this proposition has been found in contexts in which flock members usually obtain social information, namely, location of food (e.g. Krebs 1973) and threat of predation (Fallow et al 2011). Alternately, associating with similar species might be a way for species to obtain group-living benefits, which are normally linked to single-species groups, without suffering the concomitant costs of intraspecific competition (Buskirk 1976;Beauchamp 2002;Péron and Crochet 2009); this pattern is extensively documented in fish schools (Krause and Ruxton 2002).…”

“…Therefore, studies so far that have examined flock assembly have done so entirely in the context of competition (Graves and Gotelli 1993;Gó mez et al 2010). On the other hand, behavioral studies have documented positive interactions in flocks in terms of the use of heterospecific social information (Goodale and Kotagama 2005), copying of foraging behavior (Krebs 1973), and direct benefits such as feeding on prey flushed by other species' movements (e.g., Satischandra et al 2007). Such benefits could in turn lead to higher survival rates for flock participants (Jullien and Clobert 2000).…”

Bird mixed-flocks and nuclear species in a tecoma savanna in the Pantanal

“…In fact, feeding benefits are expected if insects are flushed by flock mates or due to copying behavior (Powell, 1985). In either case, a species would require the presence and close proximity of another species that employed a specific kind of foraging behavior (Krebs, 1973;Munn and Terborgh, 1979). Although the analysis on specific association between foraging species was beyond the scope of this study, during the observations on foraging tactics, no interaction suggested that a species foraged focusing another one, which might provide increased chances of prey capture.…”

Feeding and social behavior of the piabanha, Brycon devillei (Castelnau, 1855) (Characidae: Bryconinae) in the wild, with a note on following behavior

“…There is, for example, a wealth of literature on the adaptive significance of multi-species feeding associations for bird species (Crook, 1965;Cody, 1971;Krebs, 1973;Bertram, 1978). However, studies concerning the ecological significance of foraging associations are recent and restricted to few studies for fish (Lukoschek & McCormick, 2000), and even more rare for those species from Neotropical freshwaters (Sazima, 1986;Teresa & Carvalho, 2008;Leitão et al, 2007;Garrone-Neto & Sazima, 2009).…”