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Producer-Scrounger Roles And Joining Based On Dominance In A Free-Living Group Of Mexican Jays (Aphelocoma Ultramarina), John Mccormack, Piotr Jablonski, Jerram Brown
Producer-Scrounger Roles And Joining Based On Dominance In A Free-Living Group Of Mexican Jays (Aphelocoma Ultramarina), John Mccormack, Piotr Jablonski, Jerram Brown
John E. McCormack
While foraging, animals often exploit group members to obtain food. One way to describe this behaviour is with the producer-scrounger (PS) model, where scroungers use social interaction to obtain food discovered by producers. Mexican jays (Aphelocoma ultramarina) are a groupforaging species with a linear dominance hierarchy. We studied interactions in a free-living foraging group to determine (1) if foraging interactions can be explained with the PS model, (2) if these roles are consistent and (3) if dominance or relatedness affects joining frequency. We recorded board-flipping, eating, and joining events during sets of feeding trials. We show that Mexican jays use …
Recent Postglacial Range Expansion Drives The Rapid Diversification Of A Songbird Lineage In The Genus Junco, Borja Milá, John Mccormack, Gabriela Castañeda, Robert Wayne, Thomas Smith
Recent Postglacial Range Expansion Drives The Rapid Diversification Of A Songbird Lineage In The Genus Junco, Borja Milá, John Mccormack, Gabriela Castañeda, Robert Wayne, Thomas Smith
John E. McCormack
Pleistocene glacial cycles are thought to have played a major role in the diversification of temperate and boreal species of North American birds. Given that coalescence times between sister taxa typically range from 0.1 to 2.0 Myr, it has been assumed that diversification occurred as populations were isolated in refugia over long periods of time, probably spanning one to several full glacial cycles. In contrast, the rapid postglacial range expansions and recolonization of northern latitudes following glacial maxima have received less attention as potential promoters of speciation. Here we report a case of extremely rapid diversification in the songbird genus …