White River National Wildlife Refuge Research Articles

Not all sanctuaries are created equal: variation in protected area selection by wintering mallards

AbstractPublic lands managed for wildlife frequently provide various forms of sanctuary to increase residency times and allow access to energetic and other habitat resources for waterfowl. The influence of sanctuary type and disturbance regime on resource use and fine‐scale movements of waterfowl has not been investigated extensively using currently available transmitter technologies. We examined mallard (Anas platyrhynchos) use of various types of waterfowl sanctuary and non‐sanctuary areas in the Mississippi Alluvial Valley region of eastern Arkansas, USA, during winters of 2019–2021. We deployed 105 global positioning system transmitters on mallards at 4 closed‐access spatial sanctuaries on or adjacent to Dale Bumpers White River National Wildlife Refuge. We used hourly transmitter locations to examine mallard use of public sanctuary areas, public hunt areas, and private lands using integrated step selection analysis. Public sanctuary areas provided varying levels of protected status, public hunt areas allowed for varying levels of hunting intensity by duck hunters, and private lands were open to waterfowl hunting and other forms of private uses but may or may not have been hunted at any specific frequency. Mallards selected spatial sanctuary and avoided public hunt areas, other sanctuary types, and private lands during the day. In contrast, mallards selected for private lands over spatial sanctuary at night. Mallards tended to avoid areas that allowed duck hunting or used them during the night when risk of harvest mortality was removed. After the hunting season closed, mallards began using areas that previously allowed duck hunting during the day, suggesting that risk was the primary factor influencing site use. Moreover, mallards were 1.6 times more likely to use public daily hunt areas and 2.1 times more likely to use private lands potentially open to hunting during the day than spatial sanctuary 2 weeks after the close of duck hunting season in February. Spatial sanctuaries appear more effective in influencing mallard use than temporal sanctuaries or inviolate sanctuaries, which are commonly used by state and federal agencies. Partial daily, daily, or activity‐specific (e.g., no hunting past noon, no hunting 3 days/week, no waterfowl hunting) closures to encourage mallard use of temporal sanctuaries do not appear to reduce the perceived harvest‐related risk to mallards enough for them to view these areas as accessible or significantly increase their use.

Regeneration trends along climate gradients in Taxodium distichum forests of the southeastern United States

The development of relict vegetation at the edges of some ecosystems has taken place particularly in environments where the regeneration of foundational species is declining. As an important stage of regeneration in the Taxodium distichum, this study explored the relationship of cone volume and seed number across environmental gradients in the Mississippi River Alluvial Valley (MRAV) and northern Gulf of Mexico Coast (GOM) in a long-term network of forested wetlands (North American Baldcypress Swamp Network (NABCSN)) from 2007 to 2019. Resembling spheroids, the volumes of Taxodium distichum cones were based on the measured dimensions of the cones collected in swamps across southeastern environmental gradients. Cones with larger volumes also had larger numbers of seeds (r2 = 0.423, F = 113.9, p < 0.0001; Linear regression equation: Seed number per cone = 9.8925223 + 0.8854056* Cone volume cm3). Mean cone volumes were related to water availability with highest volumes in locations with moderate amounts of total annual precipitation (e.g., White River National Wildlife Refuge (NWR) Arkansas, Tensas NWR Louisiana, and Morgan Brake NWR Mississippi), and longer periods of annual percent time of site drawdown. Cone volume was high in 2018 following the 2017 mega-flood in the Mississippi River Alluvial Valley (MRAV) generated by Hurricane Harvey. Mean annual air temperature was not related to cone volume. Along the Gulf Coast, mean cone volume increased from east to west from Florida to Texas. Especially near the edge of the range of T. distichum forests, smaller cones may be related to regeneration failure and lower seed numbers to support regeneration. A better understanding of regeneration constraints can inform managers of the emergence of relict status in these forests.

A test of the Swainson's warbler habitat suitability index model

ABSTRACTWe tested a recent Habitat Suitability Index (HSI) model proposed for the Swainson's warbler (Limnothlypus swainsonii; a species of conservation concern in the southeastern United States) using data on habitat, bird occupancy, and abundance collected at White River National Wildlife Refuge, Saint Francis National Forest, and Big Island in Arkansas between 2005 and 2010. The Swainson's warbler HSI includes a combination of 6 variables: landform, landcover, successional age class, forest patch size, proportion forest in a 1‐km radius, and small‐stem density (&lt;2.5 cm diam breast ht; these variables are combined to produce scores ranging 0–1, representing unsuitable to optimal habitat. Mean HSI scores were significantly lower ( = 0.65, n = 99) for sites occupied by Swainson's warblers compared with unoccupied locations ( = 0.78, n = 177) at White River National Wildlife Refuge and Big Island, contrary to our expectation for a useful model. We also found that Swainson's warbler abundances were not correlated with HSI scores both at Saint Francis National Forest and at White River National Wildlife Refuge. Our tests of the current Swainson's warbler HSI model demonstrate that it was not an effective predictor of Swainson's warbler occupancy and was not a reliable indicator of warbler habitat at the scale of our study areas. We propose a new suitability function called proportion elevation that takes relative elevation into account at potential sample locations that may improve the model. Specifically, this function should index the likelihood a site is infrequently flooded and should support the development of a thick understory, a habitat feature that has been demonstrated to be important to Swainson's warblers. © 2014 The Wildlife Society.

Chimney Swifts (Chaetura pelagica) Nest in Tree Cavities in Arkansas

Abstract We report the first records of tree-nesting Chaetura pelagica (Chimney Swifts) in Arkansas from the White River National Wildlife Refuge (WRNWR). These represent the only well-documented reports of tree-nesting swifts for many decades in the lower Mississippi Valley. The WRNWR may support a large population of tree-nesting swifts.

Origins and genetic structure of black bears in the Interior Highlands of North America

Although black bears (Ursus americanus) were believed to be extirpated from the Interior Highlands of North America by the early 1900s, populations have recently recovered, aided in part by reintroductions in Arkansas. Today black bears can be found in the Ozark and Ouachita National Forests of northern and western Arkansas, the White River National Wildlife Refuge in eastern Arkansas, and the Ozark region of southern Missouri. Previous genetic studies have investigated the effects of translocating black bears from Minnesota and Manitoba, Canada, into the Ozark and Ouachita National Forests between 1958 and 1968, with differing results. We used nuclear microsatellite loci to infer the genetic structure of black bears across the Interior Highlands and to investigate the sources of bears found today in southern Missouri. Our results suggest that the Ozark population was strongly influenced by the reintroductions, whereas the Ouachita population was influenced to a lesser degree. Although the majority of bears in the Ozark region of Arkansas and Missouri represent a single genetic unit, bears in Webster County, Missouri, may represent a remnant of the historical population of the region. Our results confirm that the bear population in the White River National Wildlife Refuge is strongly differentiated genetically from other Arkansas populations and support previous reports that the Ouachita bear population may have resulted from an admixture of a remnant population and reintroduced bears.

What factors explain differential use within Swainson's Warbler (Limnothlypis swainsonii) home ranges?

ABSTRACT. Why individuals use some areas within a home range more than others is poorly understood. One factor that may drive differential use is habitat heterogeneity. We radiotracked 37 male Swainson's Warblers (Limnothlypis swainsonii) at two sites in eastern Arkansas, St. Francis National Forest and White River National Wildlife Refuge. We calculated 95% kernel home ranges and designated areas within and outside of the 55% isopleth as the core area and low-use area for each bird, respectively. We then compared habitat characteristics among used points in core areas, used points in low-use areas, and randomly selected points within home ranges. We predicted that core-area points would have the highest-quality habitat, low-use points would have intermediate-quality habitat, and random points would have the poorest-quality habitat. We found that, in most cases, there were no habitat differences between core-area and low-use points, but used areas differed from randomly selected points. Core-area and low-...

Home Range, Habitat Use, and Nest Site Characteristics of Mississippi Kites in the White River National Wildlife Refuge, Arkansas

We located 39 Mississippi Kite (Ictinia mississippiensis) nests during the 2004 and 2005 breeding seasons in the White River National Wildlife Refuge in the Mississippi Alluvial Valley of Arkansas, USA. Radio transmitters were placed on seven adult and eight juvenile kites; 649 locations based on ground telemetry and 393 locations from aircraft were recorded for six adults (n = 5 males, 1 female) and five juveniles (n = 2 males, 3 females). The mean 90% kernel home range was 3,098 ha for adult kites (n = 6) and 439 ha (n = 5) for juveniles. Radio-marked Mississippi Kites significantly used mature forest (65.6%), second growth (15.5%), and water (10.0%) relative to availability (59.6, 11.5, and 7.1%, respectively). Agriculture fields (6.5%) and wetlands (1.5%) were used significantly less within the home ranges of kites relative to availability (17.6 and 3.9%, respectively). Tree height, diameter at breast height (dbh), and height of nest tree emergence above the surrounding trees were significantly greater for nest sites than randomly-selected overstory trees. Nest trees were significantly closer to the edge than randomly-selected trees. Most (57%) Mississippi Kite nests were in crotches of secondary branches in the nest tree. Conservation of super-emergent trees and mature forests is needed for nesting and foraging areas. Second-growth forest should be allowed to mature (>75 years) and uniform canopies should be avoided.

Effects of Exploitation on Black Bear Populations at White River National Wildlife Refuge

Abstract: We live‐trapped American black bears (Ursus americanus) and sampled DNA from hair at White River National Wildlife Refuge, Arkansas, USA, to estimate annual population size (N), growth (γ), and density. We estimated N and γ with open population models, based on live‐trapping data collected from 1998 through 2006, and robust design models for genotyped hair samples collected from 2004 through 2007. Population growth was weakly negative (i.e., 95% CI included 1.0) for males (0.901, 95% CI = 0.645–1.156) and strongly negative (i.e., 95% CI excluded 1.0) for females (0.846, 95% CI = 0.711–0.981), based on live‐trapping data, with N from 1999 to 2006 ranging from 94.1 (95% CI = 70.3–137.1) to 45.2 (95% CI = 27.1–109.3), respectively, for males and from 151.4 (95% CI = 127.6–185.8) to 47.1 (95% CI = 24.4–140.4), respectively, for females. Likewise, mean annual γ based on hair‐sampling data was weakly negative for males (0.742, 95% CI = 0.043–1.441) and strongly negative for females (0.782, 95% CI = 0.661–0.903), with abundance estimates from 2004 to 2007 ranging from 29.1 (95% CI = 21.2–65.8) to 11.9 (95% CI = 11.0–26.9), respectively, for males and from 54.4 (95% CI = 44.3–77.1) to 27.4 (95% CI =24.9–36.6), respectively, for females. We attribute the decline in the number of females in this isolated population to a decrease in survival caused by a past translocation program and by hunting adjacent to the refuge. We suggest that managers restructure the quota‐based harvest limits until these growth rates recover.

Effects of Exploitation on Black Bear Populations at White River National Wildlife Refuge

Effects of Exploitation on Black Bear Populations at White River National Wildlife Refuge

Factors Influencing Home-Range Size of Swainson's Warblers in Eastern Arkansas

Abstract. Understanding factors affecting space-use patterns can lead to improved knowledge of the ecology and habitat needs of a species. We radiotracked 37 male Swainson's Warblers (Limnothlypis swainsonii) at two sites in eastern Arkansas, White River National Wildlife Refuge, a bottomland site, and St. Francis National Forest, a site with birds in both bottomlands and uplands. We found substantial variation in home-range size and evaluated habitat and nonhabitat predictors of home-range size by information-theoretic techniques. We also evaluated how breeding phase affected home-range size. Several habitat variables were good predictors of home-range size, including understory density, vine-stem density, and other stem-density variables. Overall, vine-stem density and understory density were the best predictors of home-range size, and nonhabitat factors were poor predictors. A three-variable model including density of giant cane (Arundinaria gigantea), vine, and shrub stems as separate variables was a ...

Habitat and Landscape Effects on Brood Parasitism, Nest Survival, and Fledgling Production in Swainson's Warblers

ABSTRACT Numerous factors, including nest predation and brood parasitism, may limit populations of neotropical migratory birds. However, nest predation and brood parasitism are not constant, and temporal, biological, habitat, and landscape factors can affect the likelihood of these events. Understanding these patterns is important for species of conservation concern for which managers seek to provide quality habitat. One such species, the Swainson's warbler (Limnothlypis swainsonii), is a neotropical migrant that breeds primarily in bottomland hardwood forests of the southeastern United States. Little is known of factors influencing reproductive success of this rare, yet locally abundant, species. From 2004 through 2007, we examined factors influencing reproductive success of Swainson's warblers at 2 sites in eastern Arkansas, USA, St. Francis National Forest and White River National Wildlife Refuge. We used 2‐stage modeling to assess the relationship between 1) temporal and biological, and 2) habitat and landscape factors and brood parasitism, nest survival, and fledgling production. Brood parasitism was greater in this population (36%) than reported elsewhere (≤ 10%), but decreased throughout the breeding season. Nest survival was comparable to or lower than in other populations of this species and increased throughout the breeding season. The probability of brood parasitism was greater near forest edges. Although nests of Swainson's warblers were often associated with giant cane (Arundinaria gigantea), nest survival had a weak negative association with cane density. For nests that were successful, the best predictor of number of Swainson's warblers fledged was brood‐parasitism status: nonparasitized nests fledged 2.75 young, whereas parasitized nests fledged 0.60 Swainson's warblers. Our findings suggest that managing and restoring relatively high‐elevation bottomland forests that are located far from agricultural edges should increase Swainson's warbler productivity.

Mitochondrial DNA Phylogeography of Black Bears (Ursus americanus) in Central and Southern North America: Conservation Implications

The American black bear (Ursus americanus) experienced a significant range contraction during the 19th and 20th centuries due to a variety of anthropogenic factors. Although previous molecular studies of black bears provided insight into historic and contemporary forces shaping phylogeographic patterns, none included black bears from the central part of the species distribution. Understanding the historical aspects of the connectivity and genetic differentiation of black bears in this region is important for proper management and conservation programs, but this understanding is confounded by poorly documented translocation efforts and population expansion. To address these issues, we generated mitochondrial DNA sequence data for 409 black bears from 15 populations in North America. Two sampling localities (Manitoba, Canada, and Minnesota) were source populations for translocation into western Arkansas and Louisiana. Major conclusions from our study include: black bears in western Arkansas were affected genetically by the translocation program; eastern Oklahoma has been repopulated by westward expansion of bears from Arkansas with a mixture of translocated bears and remnant individuals; black bears in Louisiana were not affected genetically by the translocation program; black bears in western Texas and northern Mexico dispersed there from the southeastern United States; and bears in White River National Wildlife Refuge (eastern Arkansas) share closer genetic affinities with U. a. luteolus than they do with the widespread U. a. americanus.

Reproductive success and causes of nest failures for Mississippi Kites: A sink population in eastern Arkansas?

In the White River National Wildlife Refuge, we located and monitored 39 Mississippi Kite (Ictinia mississippiensis) nests during the 2004 and 2005 breeding seasons to examine reproductive success and causes of nesting failures. Nest failures were documented using five video recording systems. All kite nests not monitored with a video recording system were observed every 3 or 4 d. The apparent reproductive success during this study was 28.2% (n = 39 nests). Using the Mayfield estimator, we determined the nest success to be 36.3% over 1226 nest-exposure days with a daily nest survival of 0.9837. We recorded seven nest failures and eight probable predation attempts. Predation was the most common cause of nest failures of video observed nests (57%), with western rat snakes (Elaphe obsoletd) being the most common predator of kite eggs and nestlings. Other observed nest failures included nest abandonment, a chick falling out of a nest, and an infertile egg. Reproductive success reported in this study was the second lowest (28%) of all Mississippi Kite studies. This low reproductive success rate is likely not adequate to support a viable population in the White River National Wildlife Refuge, indicating this may currently be a sink population.

Vegetation characteristics of Swainson’s warbler habitat at the White River National Wildlife Refuge, Arkansas

The Swainson’s warbler (Limnothlypis swainsonii Audubon) is a species of concern within forested wetlands across the southeastern U.S. Previous studies involving low-elevation sites may not have adequately represented the habitat affinities of this species. We examined relationships between Swainson’s warbler occupancy and vegetation structure at relatively high-elevation bottomlands at White River National Wildlife Refuge (WRNWR). In 2004 and 2005, we systematically surveyed 1453 sites and collected vegetation data at 70 occupied sites (< 5% occupancy) and 106 randomly selected unoccupied sites. Occupied sites had greater canopy cover, density of cane (Arundinaria gigantea Walt. Chapm.) and shrub stems, litter depth, and greater and more uniform understory vegetation density than unoccupied sites. Moreover, cane and understory vegetation density were associated with more persistent habitat use. Ultimately, cane stem density was the best predictor of Swainson’s warbler occupancy with an AICcin weight of 99% over all models considered. Overall, our results suggest that cane, dense understory structure, and a well-developed leaf-litter layer are key habitat components for Swainson’s warblers at WRNWR. These findings are especially relevant given the substantial decline of canebrakes throughout the Southeast. Swainson’s warbler management should include enhancement of canebrakes via manipulations that mimic natural disturbances.

Agricultural Pesticides in Mississippi Delta Oxbow Lake Sediments During Autumn and Their Effects on Hyalella azteca

Agricultural pesticide contamination of sediments from five Mississippi Delta oxbow lakes and their effects and bioavailablity to Hyalella azteca were assessed during a low-application season-autumn. Three reference oxbow lakes were located in the White River National Wildlife Refuge (WRNWR), Arkansas and two impaired lakes, according to the US Environmental Agency Sect. 303 (d) Clean Water Act, were located in Mississippi. Surface sediment (top 5 cm) was collected at three sites within each lake and analyzed for 17 current and historic-use pesticides and metabolites. Chronic 28-day H. azteca sediment bioassays and pesticide body residue analyses were completed to determine the degree of biological responses and bioavailability. The greatest number of detectable pesticides in WRNWR and 303 (d) sediment samples was 9 and 12, respectively, with historic-use pesticide metabolite, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] ubiquitous. No significant (p > 0.05) differences in animal survival were observed among sites. Animal growth was significantly (p < 0.05) less at only one site in a 303 (d)-listed lake (Macon Lake). Only six pesticides were observed in H. azteca with current-use pesticides detected at three sites; historic-use pesticides and metabolites detected at 11 sites. Animal body residues of a historic-use pesticide (dieldrin) and metabolite (p,p'-DDE) were associated with observed growth responses. Results show limited current-use pesticide contamination of sediments and H. azteca body tissues during autumn and that historic-use pesticides and metabolites are the primary contributors to observed biological responses.

Similarities Between Campephilus Woodpecker Double Raps and Mechanical Sounds Produced by Duck Flocks

Abstract The search for the Ivory-billed Woodpecker (Campephilus principalis) in eastern Arkansas and northwestern Florida has yielded double raps recorded by autonomous recording units (ARUs) in White River National Wildlife Refuge and along the Choctawhatchee River, respectively. These double raps have been presented as suggestive evidence for the presence of the species in those regions. We present data comparing double raps produced by wing collisions from an aerial Gadwall (Anas strepera) flock to double raps documented by ARUs. Close similarities in amplitude ratios, peak-to-peak times between raps, and auditory quality between ARU recordings and wing collisions from a Gadwall flock illustrate the ability of flying ducks to produce sounds easily mistaken for the double raps of Campephilus woodpeckers. All ARU double raps suggesting the presence of an Ivory-billed Woodpecker should be reconsidered in light of the phenomenon of duck wingtip collisions, especially those recorded during winter months wh...

Growth and Sustainability of Black Bears at White River National Wildlife Refuge, Arkansas

The black bear (Ursus americanus) population at White River National Wildlife Refuge is isolated and genetically distinct, but hunting occurs adjacent to refuge boundaries and females with cubs are removed annually for a reintroduction project. We trapped and radiotracked bears to determine level of exploitation and compare methods for estimating population growth and sustainability. We captured 260 bears (113 M:147 F), 414 times, from 1998 through 2003. Survival estimates based on radiotracking and mark–recapture indicated that hunting and translocations were significant sources of loss. Based on mark–recapture data (Pradel estimator), the annual population growth rate (λ) averaged 1.066 (SE = 0.077) when translocation removals occurred and averaged 0.961 (SE = 0.155) when both harvest and translocations occurred. Estimates of λ based on a population simulation model (program RISKMAN) averaged 1.061 (SD = 0.104) and 1.100 (SD = 0.111) when no removals occurred, 1.003 (SD = 0.097) and 1.046 (SD = 0.102) when translocations occurred, and 0.973 (SD = 0.096) and 1.006 (SD = 0.099) when both harvest and translocations occurred, depending on the survival rate estimates we used. The probability of population decline by >25% over a 10-year period ranged from 13.8 to 68.8%, given our estimated removal rates. We conclude that hunting and translocation losses are at or exceed the maximum the population is capable of sustaining. Although extinction risks of this important bear population are low over the near term, it should continue to be closely monitored by state and federal agencies. The mark–recapture method we used to estimate λ proved to be a reliable alternative to more costly population modeling methods.

Factors affecting settling, survival, and viability of black bears reintroduced to Felsenthal National Wildlife Refuge, Arkansas

Abstract We used radiotelemetry and population modeling techniques to examine factors related to population establishment of black bears (Ursus americanus) reintroduced to Felsenthal National Wildlife Refuge (NWR), Arkansas. Our objectives were to determine whether settling (i.e., establishment of a home range at or near the release site), survival, recruitment, and population viability were related to age class of reintroduced bears, presence of cubs, time since release, or number of translocated animals. We removed 23 adult female black bears with 56 cubs from their winter dens at White River NWR and transported them 160 km to man-made den structures at Felsenthal NWR during spring 2000–2002. Total movement and average circuity of adult females decreased from 1 month, 6 months, and 1 year post-emergence (F2, 14 =19.7, P <0.001 and F2, 14 =5.76, P =0.015, respectively). Mean first-year post-release survival of adult female bears was 0.624 (SE=0.110, SEinterannual= 0.144), and the survival rate of their c...

Notes and Double Knocks from Arkansas

In the search for ivory-billed woodpeckers ( Campephilus principalis ) in the Big Woods region of eastern Arkansas [“Ivory-billed woodpecker ( Campephilus principalis ) persists in continental North America,” Reports, 3 June, p. [1460][1]], our unattended digital autonomous recording units (ARUs) recorded over 17,000 hours of ambient sound at 153 sites between 18 December 2004 and 31 May 2005. Review and analysis of these recordings are ongoing, and a full account will be published when analyses are complete. Here we briefly describe examples of the possible nasal “kent” notes and “doublek-nock” display drums mentioned in our Report and provide them as supporting online material (SOM) ([1][2]). ![Figure][3] A painting of the ivory-billed woodpecker and the device used to record its calls.CREDITS: (PAINTING) LARRY CHANDLER; (PHOTO) SUSAN SPEAR, CORNELL LABORATORY OF ORNITHOLOGY On four different mornings in January 2005, a single ARU in the White River National Wildlife Refuge (NWR) recorded a sequence of kent-like vocalizations. The four sequences, which lasted 8 to 41 s and contained between 11 and 26 notes, are extremely similar; the recording of 29 January (audio S2) is typical of them. In the same area, experienced observers have heard blue jays ( Cyanocitta cristata ) produce atypical notes resembling these ARU recordings. Quantitative comparisons of these kent-like sounds with sounds of known ivory-bills (SOM text; audio S1), white-breasted nuthatch ( Sitta carolinensis ), and the most kent-like notes of blue jay in the collection of the Cornell Laboratory of Ornithology's Macaulay Library indicate that the notes recorded by the ARU are most similar to those of ivory-bills. Sounds that are strikingly similar to the double knocks of other Campephilus woodpeckers (SOM text; audio S3) were recorded by ARUs in several areas of the White River and Cache River NWRs. One recording (audio S4), made 1.3 km from the site of the kent-like notes discussed above at 0645 local time on 24 January, includes a low-amplitude, apparently distant double knock followed 3.5 s later by a higher-amplitude, apparently closer double knock. Although the sequence and cadence of this recording match an exchange between two individuals of a Campephilus woodpecker, the relative amplitude of the separate strikes in each double knock is atypical (SOM text). Additional descriptions and discussion of our acoustic data are available at [www.birds.cornell.edu/ivory/field/listening][4]. Further acoustic monitoring and field observation (including intensive efforts to record a large sample of the vocal repertoire of local blue jays) are planned for the areas where these recordings were made. 1. [↵][5]The SOM is available on Science Online at . [1]: /lookup/doi/10.1126/science.1114103 [2]: #ref-1 [3]: pending:yes [4]: http://www.birds.cornell.edu/ivory/field/listening [5]: #xref-ref-1-1 View reference 1 in text

Assessing American black bear habitat in the Mobile–Tensaw Delta of southwestern Alabama

American black bears (Ursus americanus) have been extirpated from all but a few areas in southwestern Alabama, and the remaining habitat is being rapidly lost to development. Remnant bear populations exist near extensive (>125,000 ha) bottomland hardwood forests in the Mobile–Tensaw Delta (MTD), but those bottomland areas are rarely used by bears. Reintroduction of black bears to the MTD may improve viability of the remaining bear populations in southwestern Alabama. To evaluate the suitability of this area for bears, we compared habitat conditions at the MTD with similar alluvial habitats at White River National Wildlife Refuge (White River NWR), where bears are numerous. We measured overstory, midstory, and understory vegetation in the MTD and on the North and South management units at White River NWR. We used principal components analysis and principal variable selection to identify 9 variables associated with 5 principal components (hard mast, soft mast, cavity tree availability, large tree availability, and total basal area) that best explained variation among study areas. Differences among the study areas were associated with hard mast, soft mast, and cavity tree availability (P ≤ 0.001). Hard and soft mast production in the MTD was lower than at White River NWR, but we believe it was adequate. However, suitable den trees, which may be a critical habitat component given the duration and severity of winter flooding, appeared to be lacking in the MTD.