Wind energy development represents significant challenges and opportunities in contemporary wildlife management. Such challenges include the large size and extensive placement of turbines that may represent potential hazards to birds and bats. However, the associated infrastructure required to support an array of turbines—such as roads and transmission lines—represents an even larger potential threat to wildlife than the turbines themselves because such infrastructure can result in extensive habitat fragmentation and can provide avenues for invasion by exotic species. There are numerous conceptual research opportunities that pertain to issues such as identifying the best and worst placement of sites for turbines that will minimize impacts on birds and bats. Unfortunately, to date very little research of this type has appeared in the peer‐reviewed scientific literature; much of it exists in the form of unpublished reports and other forms of gray literature. In this paper, we summarize what is known about the potential impacts of wind farms on wildlife and identify a 3‐part hierarchical approach to use the scientific method to assess these impacts. The Lower Gulf Coast (LGC) of Texas, USA, is a region currently identified as having a potentially negative impact on migratory birds and bats, with respect to wind farm development. This area is also a region of vast importance to wildlife from the standpoint of native diversity, nature tourism, and opportunities for recreational hunting. We thus use some of the emergent issues related to wind farm development in the LGC—such as siting turbines on cropland sites as opposed to on native rangelands—to illustrate the kinds of challenges and opportunities that wildlife managers must face as we balance our demand for sustainable energy with the need to conserve and sustain bird migration routes and corridors, native vertebrates, and the habitats that support them.
Most northern pintails (Anas acuta; hereafter pintails) in the Central Flyway winter within the Gulf Coast and adjacent rice prairies of Texas, USA. However, wintering habitat has declined in this region as a result of decreased rice production and changes in land use. Because pintails exhibit high winter site fidelity, more pintails are likely to rely on adjacent coastal habitats during winter as freshwater habitats along the Texas coast disappear. However, few studies have investigated the diet of pintails in estuarine environments. We estimated the composition and quality of the diet of pintails wintering along the lower Texas coast, and we compared our estimates to those for pintails in freshwater habitats. Proximate composition and true metabolizable energy (TME) were estimated for 4 foods in the diet of 253 pintails collected along the lower Texas coast during October‐February 1997–1998 and 1998–1999. Shoalgrass (Halodule wrightii) rhizomes, wigeongrass (Ruppia maritima) seeds, dwarf surf clams (Mulinia lateralis), marine gastropods, and Gammarus amphipods comprised most of the pintail diet. Pintail diets in coastal habitats contained smaller proportions of protein and fat and a large proportion of ash compared to diets of pintails from freshwater habitats. As a result, the diet of pintails wintering along the lower Texas coast provided about half the TME of diets of pintails wintering in freshwater habitats. Because pintails rely on endogenous reserves acquired during winter and spring migration to support egg production, pintails wintering in Texas may experience greater reductions in recruitment and survival if displaced to coastal habitats.
Abstract.We report on the habitat associations of 21 species of grassland birds overwintering in or migrating through southern Texas, during 1991-1992 and 1992-1993. Ninety percent of our grassland bird observations were made during winter and spring, and only 10% occurred during fall. Grassland species made up a high proportion of the total bird densities in grassland and shrub-grassland habitats, but much lower proportions in the habitats with more woody vegetation. Fewer grassland species were observed in grassland and woodland than in brushland, parkland, and shrub-grassland habitats. Grassland birds generally were found in higher densities in habitats that had woody canopy coverage of < 30%; densities of grassland birds were highest in shrub-grassland habitat and lowest in woodland habitat. Species that are grassland specialists on their breeding grounds tended to be more habitat specific during the nonbreeding season compared to shrub-grassland specialists, which were more general in their nonbreeding-habitat usage. Nonetheless, our data demonstrate that grassland birds occur in a variety of habitats during the nonbreeding season and seem to occupy a broader range of habitats than previously described.
Habitat fragmentation is considered a contributing factor to declining populations of northern bobwhite (Colinus virginianus). Some population strongholds exist within large expanses of habitat; however, many regions of the species' range have become fragmented and populations therein have become nearly extirpated. Our objectives were to determine whether combined habitat management and bobwhite translocation could restore bobwhite populations in habitat patches within a fragmented landscape. We translocated 550 bobwhites to 2 sites (≥660 ha; Caldwell and Fayette counties) in the Post Oak Savannah ecoregion of Texas, USA, during 2004–2006. We compared survival, home‐range size, and reproduction between translocated bobwhites in a fragmented landscape and resident bobwhites in contiguous habitat (Brooks County). Pooled over the 3‐year study, translocated bobwhites had lower survival (6 Apr–15 Aug, 2004–2006; Ŝ = 0.35; n = 165 bobwhites) than did resident bobwhites (Ŝ = 0.56; n = 224 bobwhites; P < 0.001). Translocated bobwhites also had larger home ranges (${\bar {x}}$ = 398.1 ha; n = 55 bobwhites) than resident bobwhites (${\bar {x}}$ = 10.9 ha; n = 28 bobwhites; P = 0.003). Moreover, percent of hens nesting (95% CI = 36 ± 16.4%) and nesting rate (95% CI = 1.1 ± 0.2 nests/hen) were lower for translocated bobwhites than for resident bobwhites (79 ± 12.4% and 1.6 ± 0.3 nests/hen, respectively). Our restoration efforts were unsuccessful; relative abundance of bobwhites remained low (≤1.0 covey heard/point) on translocation sites despite intensive translocation efforts. Restoring bobwhite populations in areas with few remaining bobwhites may be beyond the realm of practical management in this fragmented ecoregion. © 2012 The Wildlife Society
The distribution of North American redheads (Aythya americana) during winter is highly concentrated in the Laguna Madre of Texas and Tamaulipas, Mexico. Redheads forage almost exclusively in the lagoon and primarily on shoalgrass (Halodule wrightii) rhizomes; however, they make frequent flights to adjacent coastal ponds to dilute salt loads ingested while foraging. We conducted 63 weekly aerial surveys during October-March 2000-2003 to record use of coastal ponds by redheads. We collected information from used and unused coastal ponds to better understand factors selected by redheads for their dietary fresh water requirements. Coastal ponds used by redheads had greater surface area, percent open water, average depth, and turbidity than unused coastal ponds. Similarly, redheads used coastal ponds with lower salinity and ammonia concentrations than unused ponds. Redheads were observed on coastal ponds >6 km from foraging areas on 95% of surveys during dry conditions in 2000-01, compared to 43% of surveys during moderately wet conditions in 2001-02 and 5% during very wet conditions in 2002-03. Finally, our data suggests that redheads rely on dietary freshwater sources throughout winter and do not reduce visitation to these coastal ponds as winter progresses.
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