Song recognition and heterospecific associations between 2 fairy-wren species (Maluridae)

Ecological flexibility and selectivity in mixed-species flock participation in birds

“…To test for the effect of specific flock mates on behavior of a focal species, we ran a separate linear regression to highlight the interactions between two species known to form tight heterospecific associations during the breeding season-the purple-backed and splendid fairywrens (Johnson et al 2018). In this model, we compared the midpoint stratum of purple-backed fairywrens with that of splendid fairywrens to determine whether the two species demonstrated flexible matching behavior with one another rather than flexibly responding to the average height of their flock mates.…”

“…Defined as two or more species foraging and moving together though a landscape, mixed-species groups (Morse 1970) are formed by many taxa including birds, fish, primates, ungulates and cetaceans (Greenberg 2000; Lukoschek and McCormick 2000; Stensland et al 2003) and are found throughout the world in a variety of ecosystems. These groups can be ephemeral or persist for long periods of time (Goodale et al 2017), and membership can be dynamic, with individuals joining and leaving at different points in time and space, or stable (Martínez and Gomez 2013; Johnson et al 2018). Much of the literature on mixed-species groups has focused on the identification of nuclear species—that is, species that contribute to the facilitation and cohesion of flocks (Moynihan 1962)—and the benefits these species may provide to satellite or follower species.…”

“…al. 2007; Gyimesi et al 2012; Johnson et al 2018) - and may be mutualistic or commensalistic. In our study system, previous studies have shown a particularly tight relationship between two flocking species - the purple-backed fairywren ( Malurus assimilis) and the splendid fairywren ( Malurus splendens) .…”

“…At our site these two fairywrens species show high rates of territory overlap, territory co-defense and group foraging behaviors. When closely associated with splendid fairywrens, purple-backed fairywrens were less vigilant, spent more time foraging and showed significant fitness benefits (Johnson et al 2018). Due to the nature of their relationship, we predict that the flexibility of behavior shown by purple-backed and splendid fairywrens will be more tightly linked with one another’s foraging behavior than that of the flocks they participate in.…”

“…3) We investigate selectivity and flexibility in the context of two species--purple-backed and splendid fairywrens--which have been previously shown to interact closely. Prior work shows that these two species co-defend territories, and association with splendid fairywrens confers foraging and predator vigilance benefits to purple-backed fairywrens (Johnson et al 2018). By exploring these patterns of selectivity and flexibility in and out of mixed-species foraging flocks, we gain a deeper understanding of how different species navigate the interplay between competitive and facilitative behaviors in mixed-species groups.…”