Foray movements are common and vary with natal habitat for a highly mobile bird

• Published in: Ecology and evolution 2024-03, Vol.14 (3), p.e11096-n/a
• Main Authors: Poli, Caroline L., Meyer, Kenneth D., Darby, Philip C., Dudek, Sarah J., Kent, Gina, Fletcher, Robert J.
• Format: Article
• Language: English
• Subjects: Animals; apparent survival; Birds; Climate change; Climate effects; Demographics; Demography; Dispersal; Dispersion; Emigration; Endangered & extinct species; Endangered species; exploration; Food; Habitat fragmentation; Habitat loss; Habitats; Hydrology; individual movement; Influence; Invasive species; Mollusks; natal habitat; Survival; wetland; Wetlands
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.11096

Understanding dispersal is central to interpreting the effects of climate change, habitat loss and habitat fragmentation, and species invasions. Prior to dispersal, animals may gather information about the surrounding landscape via forays, or systematic, short‐duration looping movements away from and back to the original location. Despite theory emphasizing that forays can be beneficial for dispersing organisms and that such behaviors are predicted to be common, relatively little is known about forays in wild populations. Theory predicts that individuals that use forays may delay dispersal and such behaviors should increase survival, yet empirical tests of these predictions remain scarce. We tested these predictions in a natural system using the critically endangered snail kite (Rostrhaumus sociabilis), a wetland‐dependent raptor. We GPS tracked 104 snail kites from fledging through emigration from the natal site across their breeding range to understand the demographic consequences of movement. We found that forays were common (82.7% of individuals tracked), and natal habitat played an important role in the initiation, execution, and outcome of foray behavior. The effect of foraying on survival was indirect, where forayers emigrated later than non‐forayers, and individuals that emigrated later had the highest survival. Poor hydrological conditions in the natal environment were especially important for eliciting forays. Finally, females responded more strongly to natal hydrology than males, making more forays and significantly longer, more distant trips. These results emphasize the fundamental role of natal habitat for determining behavioral patterns, strengthen links between individual movement decisions and their demographic consequences, and provide an important behavioral focal point for interpreting movement tracks that would not otherwise be captured by conventional movement models. Despite theory predicting the benefits of forays for dispersal, there is relatively little empirical evidence of forays and even less on their fitness consequences. We address this gap using an extensive GPS‐tracking dataset from snail kites tracked from fledging through emigration from the natal site, a critical life stage when many animals are vulnerable to mortality. We find that natal habitat is related to the timing, distance, and duration of forays and that foraying kites initiate dispersal later than kites who do not foray, with indirect survival benefits.