This article provides theoretical refinement and empirical specification for the breakdown variant of strain theory. It reconceptualizes the relationship between social breakdown and movement emergence in a fashion that is consistent with strands of cultural theory, phenomenology, and symbolic interactionism, and that resonates with prospect theory and research on collective action in a diversity of settings. It argues that the key to the breakdown-movement relationship resides in the actual or threatened disruption of the "quotidian"—that is, the taken-for-granted routines and attitudes of everyday life. Four conditions are especially likely to disrupt the quotidian and heighten prospects of collective action: accidents that throw a community's routines into doubt and/or threaten its existence; actual or threatened intrusion into and/or violation of citizens' sense of privacy, safety, and control; alteration in subsistence routines because unfavorable ratios of resources to claimants or demand; and dramatic changes in structures of social control. The relationship between these conditions and movement emergence is elaborated by drawing on literature on the emergence of collective action in various contexts and on our field work on homeless mobilization in eight cities. We close by exploring the implications of our analysis for understanding more fully the generality of various conditions and processes commonly thought to apply to social movement emergence.

An unusual geological setting and a high level of endemism makes the Philippine islands of great interest to biogeography. These islands lie adjacent to the continental (Sunda) shelf, yet the majority of the islands have never been directly attached to the mainland. Existing hypotheses of colonization and diversification processes have been tested across multiple taxa, but only in ahistorical contexts. We present explicit phylogenetic predictions based on these hypotheses, and then test them using new molecular datasets for four Philippine birds. Two proposed colonization routes to the northern Philippines (from mainland Asia and Palawan) are difficult to differentiate from each other, except on the basis of outgroup, as are the two routes from the south (Sulu archipelago and Sulawesi). We find unique colonization and diversification patterns for each taxon. These results contrast with expectations from Pleistocene geography, with Luzon and Mindoro indistinguishable genetically, and Negros and Panay are often nonsister taxa. Combining these data with a literature search for studies addressing these patterns, Philippine organisms shows some evidence for each proposed colonization route but the greatest support is for the two routes from Borneo. Many taxa exhibit multiple colonization events using several of these routes, contrasting with past assumptions of single colonization events. Island-by-island differentiation within the Philippines follows, with patterns reflecting colonization patterns rather than Pleistocene geography, particularly for highland species.

Understanding interactions between biota and the built environment is increasingly important as human modification of the landscape expands in extent and intensity. For migratory birds, collisions with lighted structures are a major cause of mortality, but the mechanisms behind these collisions are poorly understood. Using 40 years of collision records of passerine birds, we investigated the importance of species' behavioural ecologies in predicting rates of building collisions during nocturnal migration through Chicago, IL and Cleveland, OH, USA. We found that the use of nocturnal flight calls is an important predictor of collision risk in nocturnally migrating passerine birds. Species that produce flight calls during nocturnal migration tended to collide with buildings more than expected given their local abundance, whereas those that do not use such communication collided much less frequently. Our results suggest that a stronger attraction response to artificial light at night in species that produce flight calls may mediate these differences in collision rates. Nocturnal flight calls probably evolved to facilitate collective decision-making during navigation, but this same social behaviour may now exacerbate vulnerability to a widespread anthropogenic disturbance. Our results also suggest that social behaviour during migration may reflect poorly understood differences in navigational mechanisms across lineages of birds.

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