Reddish Egret Distribution, Abundance, and Nesting in Coastal Louisiana
Reddish Egret with backpack-style satellite telemetry unit, Rabbit Island
Louisiana's coastal zone provides ample habitat for numerous waterbird species. However, coastal Louisiana shoreline is vast, often remote, and difficult to sample effectively. Reddish Egrets (Egretta rufescens) are the rarest North American egret species, but little is known about them through their range, especially in coastal Louisiana. This is likely a consequence of their cryptic plumage and the difficulty in detecting the species during aerial colony surveys. Along with other Louisiana Department of Wildlife and Fisheries collaborators (Samantha Collins, Michael Seymour, Sam Holcomb), we sought to gain a better understanding of the species in coastal Louisiana. Specifically, we wanted to first identify key nesting colonies for the species and estimate the number of nesting pairs utilizing each colony. Second, we wanted to capture both adults and juveniles to determine the habitats they used in Louisiana, especially important foraging and roosting habitats; along with this information, we could also gain an understanding about the dispersal and migration of the species away from Louisiana. Last, we also hoped to gain a better understanding of their nesting ecology through the use of nest monitoring at select colonies to determine nest fates (i.e., nest success).
Avian Diversity, Abundance, and Nesting on Rabbit Island in Calcasieu Lake
Clapper Rail on Rabbit Island
Rabbit Island is an 89 hectare (220 acre) brackish to saline marsh island located in the middle of West Cove of Calcasieu Lake (Cameron Parish). It serves as the only Brown Pelican nesting colony in southwestern Louisiana, which was colonized by natural expansion in 2003. The only dataset available for the island focuses specifically on Brown Pelican nesting numbers and colony persistence. However, data is lacking for most of the other bird species that utilize this regionally important island. Therefore, Bruce Davis (a colleague at RWR) and I developed a project to document the seasonal diversity and abundance of avian species using Rabbit Island in early 2013. Since February 2013, we have documented 64 avian species using the island and 15-20 nesting species; the latter includes several nesting records which are the first for southwestern Louisiana.
Effects of Beach Nourishment on Seasonal Shorebird Diversity and Abundance
Western Louisiana shorelines are eroding at phenomenal rates (some up to 10 m per year), with Highway 82 in western Cameron Parish in danger of closure due to erosion (see photo to left). To prevent this closure, a beach nourishment project was slated for 9.6 km of shoreline starting in late 2013. Plans called for the dredging of sediment from sand banks approximately 30 km offshore and pumping this sediment onto the existing beach; plans also proposed to add both height and width to the beach for highway protection. Therefore, in August 2013, B. Davis and I initiated a monitoring project to determine the impacts of beach nourishment on shorebird diversity along this stretch of shoreline. We bi-weekly monitor 6 transects (4 inside the project and 2 control segments) and quarterly collect sediment samples to analyze invertebrates and sediment characteristics. Abigail Arfman, McNeese State University graduate student, continued this project in early 2014 and is conducting similar shorebird monitoring at three other beach segments across Cameron Parish until early 2016. This project will provide much needed information on the short and long-term effects of shoreline restoration projects, as well as document baseline shorebird community data for these beaches.