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Avian Interspecific Interactions Across Scales: Communities, Mixed-Species Flocks, and Individuals

Laura N Vander Meiden, University of Nebraska - Lincoln


In ecological communities, heterospecific interactions are shaped not only by the costs of competition but also by the facilitative benefits of social interactions. Avian communities have served as a key system for investigating the interplay between these interactions both in the communities as a whole and within the mixed-species flocks found within these communities. Here I investigate heterospecific avian interactions across three levels of social organization – interactions between individuals, species-level interactions within mixed-species flocks and patterns of species co-occurrence at supplemental feeding sites across a region. I review the importance of individual-level interactions in understanding complex social systems like mixed-species flocks, emphasizing that variation in traits and relationships between individuals underpin all species-level patterns we see at broader scales. I look at behavioral flexibility within mixed-species flocks and find that species in mixed-species flocks have varied strategies to control their foraging height in relation to that of their flock mates. Some species flexibly adjust their foraging height to be closer to their flock mates, others selectively join flock mates foraging at certain heights and some utilize both strategies concurrently. When delving deeper into how these strategies may impact social roles and positioning in a network of interactions within the flock, I find that – surprisingly – a species’ flexibility does not relate to the number of connections it has within the flock network. Finally, I examine how patterns of species similarity across two axes – body size and beak shape – relate to patterns of co-occurrence at bird feeders and how that relationship has changed over time. I find that across two decades species pairs with less similar beak shapes and more similar body sizes have significantly higher rates of co-occurrence over time. Thus, indicating a reduction in niche overlap while maintaining the potential anti-predation benefits of co-occurring with species of similar size. By looking at interactions across social scales I hope to bring depth and nuance to our knowledge of species interactions.

Subject Area

Ecology|Behavioral Sciences|Evolution and Development

Recommended Citation

Vander Meiden, Laura N, "Avian Interspecific Interactions Across Scales: Communities, Mixed-Species Flocks, and Individuals" (2023). ETD collection for University of Nebraska - Lincoln. AAI30575475.