Using automated telemetry to identify population connectivity and migration phenology of Snowy Plovers breeding in the Southern Great Plains

Abstract

Within-breeding season movements have not been quantified for Snowy Plovers (Charadrius nivosus) breeding on the Southern Great Plains (SGP), where suitable breeding habitat can range from less than 10 km to more than 600 km apart. This mosaic distribution of discrete patches of breeding habitat, combined with weather stochasticity and low densities of Snowy Plovers in Texas and New Mexico, increases the risk of local and regional extirpation. Further, little is known about SGP Snowy Plover migration phenology or winter habitat. We used the Motus Wildlife Tracking System to examine population connectivity, migration phenology, and winter habitat locations of adult Snowy Plovers in the SGP. Movements of Snowy Plovers during the 2017 and 2018 breeding seasons suggest little to no connectivity between the Salt Plains National Wildlife Refuge population in Oklahoma and populations in Texas and New Mexico. However, several Snowy Plovers in Texas moved to a lake formed by freshwater springs that may have provided higher-quality breeding and foraging habitat. Migrating primarily at night, we found that Snowy Plovers from a breeding area in Oklahoma made migratory movements to Texas and the Louisiana Gulf Coast. These data may be important to long-term conservation and planning efforts relative to understanding regional persistence and connectivity among breeding populations of Snowy Plovers in the SGP. Our results also highlight the need for future studies of wintering habitats used by SGP Snowy Plovers. Uso de telemetría automatizada para identificar conectividad migratoria y fenología de la migración de chorlos nevados en el sur de las Grandes Planicies Los movimientos dentro de la temporada reproductiva no han sido cuantificados en chorlos nevados (Charadrius nivosus) que anidan en el sur de las Grandes Planicies (SGP), donde los hábitats reproductivos disponibles se encuentran separados de 10 a más de 600 km uno del otro. Esta distribución de mosaicos de parches discretos de hábitat reproductivo, combinado con estocasticidad en el estado del tiempo y las bajas densidades de chorlos nevados en Texas y Nuevo México, incrementan el riesgo de ser extirpados local y regionalmente. Además, se sabe poco sobre la fenología de la migración y hábitat de invernada del chorlo nevado en las SGP. Usamos el Sistema de Seguimiento de Vida Silvestre Motus para examinar la conectividad poblacional, fenología de la migración y localización de hábitat invernal de chorlos nevados adultos en las SGP. Los movimientos de los chorlos nevados durante las temporadas reproductivas de 2017 y 2018 sugieren poca o nula conectividad entre la población del Salt Plains National Wildlife Refuge en Oklahoma, y poblaciones en Texas y Nuevo México. Sin embargo, varios chorlos nevados de Texas se movieron a un lago formado por manantiales de agua dulce que podrían haberles provisto de hábitat reproductivo y de forrajeo de mayor calidad. Dado que migran principalmente de noche, encontramos que los chorlos nevados de un área reproductiva en Oklahoma hicieron movimientos migratorios a Texas y la costa del golfo de Luisiana. Estos datos pueden ser importantes para esfuerzos de conservación y planeación dedicados entender su preservación regionalmente, así como la conectividad entre poblaciones de chorlos nevados en las SGP. Nuestros resultados también destacan la necesidad de estudios futuros de hábitats de invernada usados por chorlos nevados de las SGP. Table S1. The number of movements made by individual tagged Snowy Plovers as well as the dates of first detection (i.e., their arrival), to each Motus tower on the Southern Great Plains, Texas, and Louisiana coast in 2017 and 2018. Fig. S1. Pearson’s correlation coefficient matrix for 10 environmental covariates collected at three study sites on the Southern Great Plains of Texas, New Mexico, and Oklahoma in 2018 and 2019, which were used in the analysis of fall migration departure date of Snowy Plovers. Fig. S2. Hourly detections (dots) of multiple Snowy Plovers at Salt Plains National Wildlife Refuge in Oklahoma before and after adding two five-element antennae. A large jump in detections (each horizontal line of detections represents one tagged Snowy Plover) can be seen immediately after placement of the two five-element Yagi antennae (red dashed line). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.