Located at the shortest overland route between the Gulf of Mexico and the Pacific Ocean, Mexico's Tehuantepec Isthmus is a globally important migratory corridor for many terrestrial bird species. The Pacific coast of the Isthmus also contains a significant wetland complex that supports large multi-species aggregations of nonbreeding waterbirds during the boreal winter. In recent years, extensive wind energy development has occurred in the plains bordering these wetlands, directly along the migratory flyway. Using recent studies of movement patterns of three marineassociated bird species -reddish egrets Egretta rufescens, brown pelicans Pelecanus occidentalis, and red knots Calidris canutus -from the northern Gulf of Mexico, we assess the use of the isthmus as a migratory corridor. Our data provide evidence that marine birds from the Gulf region regularly overwinter along the Pacific coast of Mexico and use the isthmus as a migratory corridor, creating the potential for interaction with terrestrial wind farms during non-breeding. This study is the first to describe migration by marine-associated bird species between the Gulf of Mexico and Pacific coast. These data contribute new information toward ongoing efforts to understand the complex migration patterns of mobile marine species, with the goal of informing integrated conservation efforts for species whose year-round habitat needs cross ecoregional and geopolitical boundaries.

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The reddish egret (Egretta rufescens) is the rarest heron in North America and much remains to be learned about in the ecology of the species. The reddish egret is a foraging habitat specialist and relies on shallow coastal ecosystems. There is a paucity of information on foraging habitat requirements and the availability of foraging habitat throughout the annual cycle. Characteristics of foraging habitat at locations within the Laguna Madre, Texas where reddish egrets were observed foraging were measured. These characteristics were used to conduct a geospatial analysis that estimated the spatial and temporal distributions of foraging habitat in the Laguna Madre across 120 weeks from 2012 to 2014. Reddish egrets (n = 372) foraged in an average water depth of 10.1 ± 0.68 cm and in areas with average seagrass cover of 12.3 ± 2.74%. Approximately, 75 000 ha of foraging habitat were delineated to be available in the Laguna Madre across the study period; of this, 4 003 ha were available ≥ 50% of the time. The amount of available foraging habitat was relatively high during the spring and summer, and decreased by ~50% during winter. This model-based approach can be used throughout the species' range to examine foraging habitat availability which is a current conservation need according to the Reddish Egret Conservation Action Plan.

The American Oystercatcher (Haematopus palliatus) is listed as a Species of High Concern in the United States Shorebird Conservation Plan due to a small population size and threats during its annual cycle. Previous studies of the American Oystercatcher have focused on Atlantic Coast populations; however, little is known about the reproductive success of the western Gulf Coast population. The objective of this study was to determine nest and brood survival of American Oystercatchers in Texas. A total of 337 nests and 121 broods were monitored on the Texas Gulf Coast during 2011-2013. The top model for nest survival in Program MARK included a linear decline in survival across the nesting season and as nests aged. Survival also declined as island size and foraging habitat near the nest site increased. The probability of a nest surviving from mean initiation date to hatching was 0.384 (95% CI = 0.317, 0.451). The top model for brood survival included a linear decline in survival across the season and an increase in survival as broods aged. Brood survival also varied among years and coastal region. The probability of a brood surviving from mean hatch date to 35 days after hatch ranged from 0.397 (95% CI = 0.204, 0.578) in 2013 to 0.887 (95% CI = 0.673, 0.964) in 2011 across all regions. Known causes of nest and brood loss included beach overwash, depredation, and starvation. This study provides the first estimates of nest and brood survival of the American Oystercatcher along the western Gulf Coast. The additional insight into patterns of nest and brood survival in this species will be useful for future conservation planning efforts that target breeding American Oystercatchers. Known causes of nest and brood loss included beach overwash, depredation, and starvation. This study provides the first estimates of nest and brood survival of the American Oystercatcher along the western Gulf Coast. The additional insight into patterns of nest and brood survival in this species will be useful for future conservation planning efforts that target breeding American Oystercatchers. Keywords

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