The evolution of avian migration

Abstract

The study of avian migration has reached sophisticated levels in many areas, including ecology, behaviour, and physiology. Traditional discussions of the evolution of migration, however, have been compromised for several reasons. Previous ideas concerning the ancestral home of migrant species, southern or northern, and whether a partially migratory stage always precedes a fully migratory stage, were not expressed as testable hypotheses. Plotting migratory behaviour on phylogenetic trees has become commonplace and allows tests of traditional hypotheses. Some of these studies are reviewed, lending some support for almost all of the previous ideas. Although phylogenetic mapping helps to frame questions about the evolution of migration in a testable framework, there are two serious issues. First, experimental and observational studies reveal that the expression of migratory behaviour can change rapidly within a lineage, which can violate assumptions of character mapping. In addition, a species distribution model is used to show that current conditions for obligate migratory populations of the chipping sparrow were much restricted at the Last Glacial Maximum, and that the species might have been considered a partial migrant at that time. The expression of migratory behaviour in an extant species might be an artefact of the current inter-glacial period. Only if the rate of gains and losses of migratory behaviour can be incorporated into a phylogenetic mapping exercise will the actual evolutionary pattern of migration be revealed. For example, reconstruction of the ancestral area and the evolutionary history of migratory categories in a clade of New World warblers depended on the assumptions of character state transitions. A second concern is that the trait 'migratory' is too broad for evolutionary analysis and that, if possible, the expression of hyperphagia, Zugunruhe, and navigation could be mapped individually. Loss or suppression of any of these components can lead to sedentary populations, revealing how migratory behaviour can appear and disappear rapidly.

Temperate origins of long-distance seasonal migration in New World songbirds

“…We do not interpret the emergence of Neotropical migration in Emberizoidea as de novo evolution of migratory behavior, as migration in some form likely traces much deeper in the avian tree of life (1,26,36). Rather, our study illuminates the geographic origins and history of a major migratory system during the hemisphere-wide radiation of this diverse New World lineage.…”

“…As such, early shifts of winter ranges may not represent invasions of tropical habitats as much as tracking of tropical habitat to lower latitudes to escape harsh winter conditions while maintaining breeding at high latitudes (36,40). PlioPleistocene glaciations have clearly served to modify geographic ranges and migratory distances and routes (26,41,42) and may have had an influence on more recent shifts of winter ranges out of North America in the Passerellidae (blue branches, Fig. 4).…”

“…Our foci are the major biogeographic events in lineage history that led to the evolution of the Neotropical migratory system, as opposed to the appearance or disappearance of migratory behavior in a population per se. Migratory behavior has been shown to sometimes change very rapidly (46) and is sensitive to temporally ephemeral changes, such as range oscillations during North American glacial cycles (26,41,42). Conversely, domino states are geographically broad and therefore temporally more stable and appropriate for phylogenetic analysis than are finer geographic state delineations that would capture more nuanced, but fleeting, contemporary details of migratory behavior.…”

“…3A). The complexity of this matrix illustrates the principal challenge of inferring the biogeographic histories of migratory species: many different sequences of geographic change could explain the evolution of a given migratory species' range (5,26). To overcome this challenge, we used graph theory and network analysis to extract from the rate matrix the dominant pathways of geographic evolutionary change that led to the evolution of Neotropical migration (Fig.…”

Population‐level scaling of avian migration speed with body size and migration distance for powered fliers

“…Birds have evolved highly diverse migration strategies to take advantage of favorable environmental conditions during the breeding season and avoid unfavorable conditions during the nonbreeding season (Lack 1968, Zink 2011. These strategies encompass a complete spectrum from partial to full migration conducted over short to long distances.…”