Trash-bin foragers: Innovation and spread of complex culture in suburban parrots

In the suburbs of Sydney, Australia, sulphur-crested cockatoos routinely loot lidded household waste bins to scavenge for food. In a new study, researchers document the emergence and geographic spread of innovative bin-opening behaviors in urban parrot populations, revealing the presence of a complex social learning culture in these birds. What’s more, this behavior appears to have emerged as a direct response to land-use change and urbanization, demonstrating how animal cultures could allow for local adaptation of urban animal populations in the Anthropocene. In animals, ecological novelty, including novelties unique to anthropogenic urban landscapes, can lead to cultural innovation. Generally, culture in animals involves socially learned behaviors shared among peers and between generations in a group of animals. While a variety of cultures have been observed across social species with complex cognition, identifying persistent cultures and social learning in animal species remains challenging. Recently, the sulpher-crested cockatoo, a large-brained and highly social parrot that’s become increasingly common in the cities of eastern Australia, has been observed opening household waste bins to scavenge food. While this emergent and innovative foraging behavior exploits a widely available resource unique to urban environments, whether or not it represents social learning or culture in cockatoo foraging behavior remains unknown. Barbara Klump and colleagues used a large-scale citizen science survey to map cockatoo bin opening across the greater Sydney region. According to the findings, before 2018, bin foraging was reported in only three suburbs. By late 2019, however, it had spread to 44 via social learning. Analysis of 160 direct observations of the behavior revealed distinct styles and suburb-specific approaches to how the birds opened the bins. Klump et al. describe how the innovation, spread and emergence of regional variation in this novel foraging behavior illustrate the existence of cultural complexity in this group of birds.

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