Avian movements in a modern world - cognitive challenges

Different movement patterns have evolved as a response to predictable and unpredictable variation in the environment with migration being an adaptation to predictable environments, nomadism to unpredictable environments and partial migration to a mixture of predictable and unpredictable conditions. Along different movement patterns different cognitive abilities have evolved which are reviewed and discussed in relation to an organism’s ability to respond to largely unpredictable environmental change due to climate and human-induced change and linked to population trends. In brief, migrants have a combination of reliance on memory, low propensity to explore and high avoidance of environmental change that in combination with overall small brain sizes results in low flexibility to respond to unpredictable environmental change. In line with this, many migrants have negative population trends. In contrast, while nomads may use their memory to find suitable habitats they can counteract negative effects of finding such habitats disturbed by large-scale exploratory movements and paying attention to environmental cues. They are also little avoidant of environmental change. Population trends are largely stable or increasing indicating their ability to cope with climate and human-induced change. Cognitive abilities in partial migrants are little investigated but indicate attention to environmental cues coupled with high exploratory tendencies that allow them a flexible response to unpredictable environmental change. Indeed, their population trends are mainly stable or increasing. In conclusion, cognitive abilities have evolved in conjunction with different movement patterns and affect an organism’s ability to adapt to rapidly human-induced changes in the environment

Pattern of Movement by Summer Tanagers (\u3ci\u3ePiranga rubra\u3c/i\u3e) During Migratory Stopover: A Telemetry Study

How well migratory birds meet en route contingencies depends on their ability to locate resources and avoid sources of stress in an unfamiliar setting. Exploration is a means by which migrants could collect information about the kinds, distribution and abundance of available resources and places safe from predators. We used radio-telemetry to study the movements of 24 summer tanagers (Piranga rubra) during stopover on a barrier island following migration across the Gulf of Mexico. The movement of some individuals was characterized by high linearity and low turn bias (i.e. alternating left and right turns). The combination of left- and right-hand turns while maintaining an overall linear track represents an efficient way of exploring an unfamiliar area. Other summer tanagers restricted their movements to a particular area (e.g. low directionality and high meander ratio), which may reflect less time spent in exploration. Birds that had been on the island for a day and a night displayed a pattern of movement less consistent with exploration than did \u27newly arrived\u27 birds. Given pressure to minimize migration time, the time a migrant spends in exploration probably depends on the cost of acquiring information and the benefits to be gained, the ratio of which surely varies among individuals

Activity Budgets of Summer Tanagers during Spring Migratory Stopover

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