The White-bellied Heron (<em>Ardea insignis</em>), one of the world’s rarest birds, is critically endangered with fewer than 60 individuals globally. Bhutan harbors the largest known population, offering a vital opportunity for species conservation under future climate uncertainty. This study presents Bhutan’s first nationwide, climate-informed habitat suitability model for the White-bellied Heron. Using 361 verified occurrence records from 2001 to 2024 and 24 environmental predictors including topographic, bioclimatic, and anthropogenic variables, we applied a weighted ensemble modeling framework that combines generalized linear models, generalized additive models, and random forest algorithms. Model weights were calibrated to improve predictive accuracy and ecological relevance. The framework supports spatial projections of current and future habitat distributions under Shared Socioeconomic Pathway 3 climate scenarios for the periods 2041 to 2060 and 2061 to 2100. Under baseline conditions (1996 to 2014), 8219 km² of Bhutan is identified as suitable habitat, expanding to 13,784 km² by 2100. However, projections reveal fragmentation and shifting suitability zones, particularly in unprotected districts such as Monggar and Pemagatshel. Protected areas like Royal Manas National Park retain high suitability, while others including Bumdeling Wildlife Sanctuary and Jigme Khesar Strict Nature Reserve may become unsuitable. These results should be interpreted with caution due to limitations in modeling dynamic anthropogenic pressures such as hydropower development, road expansion, and land-use change. The absence of spatial data on infrastructure footprints and fine-scale ecological filters may lead to overestimation of habitat suitability in certain regions. This study identifies protection gaps, proposes Other Effective Area-Based Conservation Measures, and emphasizes the need for connectivity and adaptive strategies. Bhutan’s proactive conservation planning offers a valuable model for climate-resilient biodiversity management.

Eastern Whip-poor-will (<em>Antrostomus vociferus</em>) populations have declined considerably since 1970, primarily because of declines in insect prey and early successional forest breeding habitat. Previous studies on Whip-poor-wills have focused on tracking movements of adults on the breeding grounds and adults on the wintering grounds, tracking migratory pathways, and quantifying occupancy, yet few studies have focused on home range scale space use and habitat selection. We tracked 10 adult Whip-poor-wills from May–August 2022 at two Rhode Island, USA state management areas, Big River and Great Swamp, and five adult Whip-poor-wills (four of which were also tracked in 2022) from May–August 2023 at Great Swamp. We used diurnal locations to estimate home ranges for each individual and the extent of home range overlap for neighboring males, paired males and females, and the same males tracked in both years, as well as habitat selection at the home-range scale. Home range sizes of males and females were not different and averaged 18.05 ha. Home ranges of neighboring males minimally overlapped whereas paired males and females had a high degree of home range overlap. The four males that were tracked at Great Swamp in both years used very similar home ranges across years, suggesting that at least some individuals show site and home range fidelity. We found no support for selection for distance to any land cover types at the population level; however, 10 of 11 individuals selected for at least one land cover type and eight of 11 individuals selected for early successional forest openings (e.g., scrub and grassland), although the pattern of selection varied between individuals. These findings, when considered along with other published works on Whip-poor-will habitat selection and occupancy, underscore the importance of active forest management to maintain habitat mosaics on known Whip-poor-will breeding grounds.

Southeast Asian dry forests experience high levels of disturbance and deforestation, resulting in significant biodiversity decline. White-rumped Falcon (<em>Neohierax insignis</em>), a species endemic to these dry forests, is classified as Near Threatened due to habitat loss and degradation. Recently, its distribution range has been extended into northwestern Thailand following an update in the distribution records, although population and habitat status in the region remain largely unknown. This study aims to address these gaps by: 1) estimating the population status of the White-rumped Falcon across dry forest patches within five protected areas in northwestern Thailand using line transect and distance sampling; 2) investigating habitat selection by comparing sites where the species was detected and not detected; and 3) defining the extent of suitable habitat using remote sensing data based on detection locations. Density could be estimated only in two protected areas, DoiWiangLa Wildlife Sanctuary (16.85 detected birds/km² and 10.03 detected groups/km²) and OpLuang National Park (7.82 detected birds/km² and 6.87 detected groups/km²), as these areas recorded sufficient detections. Habitat selection analysis indicated a preference for lowland areas with high tree density and large trees, particularly those with diameters at breast height ranging from 20 to 30 cm. The total remaining potential dry forest habitat across the study range was estimated at 61,172 km², of which 34.49% (21,098.34 km²) is currently within protected areas. Most of this lowland dry forest is located along forest margins and overlaps with areas of intense human activity. To ensure the long-term survival of this dry forest specialist, management practices must be implemented to reduce excessive disturbance and prevent large timber extraction. Continued population monitoring is essential to track changes and guide conservation efforts in this threatened ecosystem.

The Swainson’s Thrush (<em>Catharus ustulatus</em>) is one of the most common migratory passerine birds nesting in the central biogeographic region of Alaska, USA, and exhibits a Nearctic-Neotropical migration. Despite its common status, there is little published about the migration phenology, migration routes, and wintering area(s) of Swainson’s Thrushes from Alaska. Using archival light-level geolocators and archival GPS loggers, we provide the first documentation of migration routes, wintering areas, and the timing of autumn and spring migration for 16 adult male Swainson’s Thrushes from study areas in Denali National Park and Preserve and Wrangell-St. Elias National Park and Preserve, Alaska. Individuals initiated autumn migration by early September, exhibited a cross-continental migration pattern across western and central Canada, then a strong latitudinal southward migration after they reached the Great Lakes region. All birds arrived on their wintering areas in South America by mid-November. Study birds exhibited a leapfrog migration pattern, wintering farther south than birds from breeding populations at more southern latitudes. Birds initiated spring migration by late February and arrived back on their breeding grounds by late May. GPS data indicated a weak loop migration pattern during part of spring migration, with spring migration routes between 15°N and 50°N latitude being slightly west of the autumn migration routes. GPS data showed that birds made a minimum of one to three stopovers during autumn migration and one to five stopovers during spring migration. Six birds carrying GPS loggers spent five to 13 days in Colombia between 3–24 March 2019, near areas where individuals from other breeding populations have wintered, suggesting the potential importance of this area to Swainson’s Thrushes from multiple breeding populations. Our findings demonstrate that adult male Swainson’s Thrushes from our study areas complete among the longest round-trip migrations of any North American migratory passerine and indicate the importance of forested landscapes across the annual range of this species.

Forum (Response) to: Van Wilgenburg, S. L., K. J. Kardynal, and B. X. Mora Alverez. 2024. In Memoriam for Dr. Keith A. Hobson. Avian Conservation and Ecology 19(2):21. I was first introduced to Keith in 1991 by my dear friend Tony Diamond at the offices of the Ontario Region of the Canadian Wildlife Service, where I was […]

The Least Bell’s Vireo (<em>Vireo bellii pusillus</em>) is a federally endangered songbird restricted to Southern California, USA, and Baja California, Mexico. Historically abundant, it suffered a catastrophic population decline during the twentieth century due to widespread habitat destruction and the arrival of Brown-headed Cowbirds (<em>Molothrus ater</em>) within its breeding range. We monitored Least Bell’s Vireo nests and conducted cowbird removals for over 13 years in a protected natural area along the Otay River in San Diego County, California. We evaluated the effects of lay date (day of the first egg laid in each nest), nest habitat (river channel versus adjacent upland terrace), and cowbird removals on Least Bell’s Vireo brood parasitism rates and nest success. Least Bell’s Vireos nested in 11 different host plant species, but over half of vireo nests were found in the upland shrub laurel sumac (<em>Malosma laurina</em>). We located and monitored 177 Least Bell’s Vireo nests, of which 20% were parasitized. The rate of parasitized nests was strongly associated with whether cowbird removals had occurred that season (9%) or had not (35%), despite the low number of female cowbirds removed annually (1–4 females per year). We also found that nests located in the upland terrace had a lower parasitism rate compared to the river channel (12% vs. 29%), with this difference more pronounced in years without cowbird removals. These differences in parasitism rates also drove differences in nest success; only 29% of channel nests were successful versus 48% of nests on the terrace. The best model predicting cowbird brood parasitism included lay date, cowbird removals, and nest habitat (river channel versus upland terrace). Thus, recovering populations of Least Bell’s Vireos may benefit by nesting outside of riparian habitats in adjacent upland habitat due to reduced cowbird parasitism rates. Conservation and restoration of upland habitats adjacent to riparian areas may provide refugia from cowbird parasitism, allowing for continued population increases in areas with limited funding for cowbird management. Conservation of upland habitats will also increase habitat available to Least Bell’s Vireos under future drier climate scenarios.

Northern Bobwhites (<em>Colinus virginianus</em>) are a popular game species but also considered a species of conservation concern due to range-wide population declines. Colorado lies at the far northwest corner of the bobwhite range, where individuals generally face more extreme winter conditions than areas further south and east, where most bobwhite research has taken place. These edge-of-range climatic extremes may lead to differences in the utility and selection of various vegetation types and structures than those reported in studies from other regions in the bobwhite range. We used radio-marked bobwhites to assess habitat selection and movements during two nonbreeding seasons in a riparian corridor in northeastern Colorado. Bobwhites selected for greater visual obstruction (β_vis = 0.026, SE = 0.005, <em>P</em> < 0.001), percent litter cover (β_litter = 0.017, SE = 0.006, <em>P</em> = 0.004), and percent bare ground (β_bare = 0.013, SE = 0.007, <em>P</em> = 0.045). Mean daily movement distance was 247.3 m (SE = 10.4), and mean nonbreeding home range size was 50.3 ha (SE = 4.8). Surprisingly, we did not find selection for woody vegetation, which is commonly reported in other studies. Otherwise, our results were consistent with research from other regions, and confirm the importance of maintaining areas with high visual obstruction interspersed with bare patches.