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Résumé :
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During the 2020s, an unprecedented movement of Limpkins (Aramus guarauna) occurred across the eastern two-thirds of the United States. Until very recently, Limpkins in the United States were restricted from extreme southern Georgia to south Florida. Now, a few hundred individuals have been documented across >25 states, with several novel breeding populations established. We assessed historical records from the 17th century through 2024 in search of potential drivers that might explain this rapid, unprecedented movement. Although large-scale drought and flood patterns often closely align with these vagrancy patterns, it is still unclear what factors have precipitated this mass movement. Additionally, food sources such as invasive apple snails (Pomacea spp.) have previously been considered primary factors in Limpkin expansion, yet the majority of recent extralimital Limpkins are well outside the current distribution of these snail species. In these extralimital observations, Limpkins were shown to consume a variety of mollusks including native giant floater (Pyganodon grandis) and non-native Chinese mystery snail (Cipangopaludina chinensis). Examination of wing molt demonstrated that most of these extralimital records involved second year (SY) individuals. Our preliminary assessment indicates Pomacea spp. do not need to be present for extralimital movement and natal dispersal does not appear to be a primary contributor to these movements. Environmental conditions, such as drought, may be the most prominent cause of this unprecedented pattern.
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