Black Rail Inventory at Padre Island National Seashore 2024 - Open Format Dataset

The Eastern Black Rail is an elusive, federally threatened marsh bird with declining populations, making effective monitoring and habitat management critical. This study investigated Black Rail occupancy and habitat characteristics at Padre Island National Seashore (PAIS) using a combination of call-playback surveys, passive acoustic monitoring, trail cameras, and vegetation sampling. Over a survey season from March to July 2024, call-playback surveys detected Black Rails at eight locations. Both detectability and occupancy were low, with a detection probability of only 8.8% and with only 10.6% of apparently suitable habitat occupied. Vegetation sampling revealed that survey points were dominated by emergent vegetation, with limited coverage by shrubs, saltgrass, and cordgrass. The above-ground biomass (AGB) of grassy and herbaceous vegetation has been positively correlated with occupancy at other sites and the relatively low AGB observed at sites on PAIS may help explain the limited occupancy observed in this study. Black Rails typically avoid areas of extensive woody vegetation, and prescribed fire can be very effective at reducing woody vegetation encroachment. Consequently, prescribed fire is likely an effective way to manage units for continued Black Rail persistence. However, adjusting the interval between burns may be required to allow AGB to increase to a higher level in order to increase occupancy.