Scott R. Loss

The Conservation Reserve Program (CRP) is one of the most extensive private‐land conservation programs in the United States, aimed at mitigating habitat loss and supporting biodiversity in agricultural landscapes. Individual studies of CRP effects on wildlife report mixed results, necessitating a comprehensive synthesis. We conducted a meta‐analysis and vote‐counting assessment of 96 studies (1009 case studies, i.e., individual analyses of a wildlife response to a CRP predictor variable) to evaluate effects on wildlife density, occurrence, reproduction, habitat use, and species diversity. Formal meta‐analyses were performed for wildlife density and avian nest success. We found CRP generally benefited wildlife, with vote counting indicating positive effects in 32% of all comparisons (i.e., including comparisons to any type of non‐CRP land) and in 64% of comparisons to cropland. Formal meta‐analysis indicated avian nest success was significantly higher on CRP lands compared to non‐CRP lands, but CRP enrollment did not consistently increase wildlife density, likely due to species‐specific and ecological factors we did not account for. The literature was strongly biased toward birds (90% of case studies), with limited research on mammals, invertebrates, amphibians, and reptiles. High heterogeneity in effect sizes suggests that variation in conservation practices, study methodologies, and ecological contexts plays a critical role in shaping measured wildlife responses to CRP. Our results demonstrate CRP provides important benefits to wildlife, particularly by enhancing avian reproductive success. However, variation in wildlife effects highlights the need for studies that incorporate more detailed information on CRP management practices and increased research on non‐avian taxa. Addressing these gaps may provide additional information allowing for the implementation of improved conservation strategies and maximize CRP's ecological benefits in agricultural landscapes.

Climate change is recognized as a key factor driving global changes in biodiversity. Rising temperatures, altered precipitation patterns, and severe weather events pose significant threats for various taxa; however, avian species face unique challenges as many aspects of their life cycles, including breeding, migration, and non-breeding periods, are intricately linked to specific ecological conditions. For species in temperate ecosystems, there is only a short period during the annual cycle when conditions are suitable for reproduction. Stochastic and long-term changes in weather and climate can strongly influence components of avian reproduction such as egg laying date, nest success, and survival of young. These effects become more complex when accounting for the biomes species occupy and their life history traits, making it critical to synthesize existing data to refine predictions about the likely impacts of climate change and to inform conservation efforts. To address this, we conducted global vote counting analyses and meta-analyses to assess how weather and climate influence components of avian reproduction. Our vote counting analyses revealed greater breeding season average temperatures were strongly associated with earlier laying and hatch dates. Breeding season precipitation had mixed effects, with strong positive effects on breeding success but weak negative effects on productivity, highlighting the complexity of its influence. Our meta-analyses identified three significant overarching relationships across the published literature: (1) greater average breeding season temperatures were associated with earlier laying dates, with the strongest effects observed in species with minimal nest types; (2) increased breeding season temperatures were linked to reduced nestling survival; and (3) greater breeding season precipitation negatively affected nestling survival. These results highlight important effects of weather and climate on components of avian reproduction, while also revealing the complexity and context-dependent nature of these influences, emphasizing the need for conservation strategies that account for shifts in weather and climate.

Climate change is recognized as a key factor driving global changes in biodiversity. Rising temperatures, altered precipitation patterns, and severe weather events pose significant threats for various taxa; however, avian species face unique challenges as many aspects of their life cycles, including breeding, migration, and non-breeding periods, are intricately linked to specific ecological conditions. For species in temperate ecosystems, there is only a short period during the annual cycle when conditions are suitable for reproduction. Stochastic and long-term changes in weather and climate can strongly influence components of avian reproduction such as egg laying date, nest success, and survival of young. These effects become more complex when accounting for the biomes species occupy and their life history traits, making it critical to synthesize existing data to refine predictions about the likely impacts of climate change and to inform conservation efforts. To address this, we conducted global vote counting analyses and meta-analyses to assess how weather and climate influence components of avian reproduction. Our vote counting analyses revealed greater breeding season average temperatures were strongly associated with earlier laying and hatch dates. Breeding season precipitation had mixed effects, with strong positive effects on breeding success but weak negative effects on productivity, highlighting the complexity of its influence. Our meta-analyses identified three significant overarching relationships across the published literature: (1) greater average breeding season temperatures were associated with earlier laying dates, with the strongest effects observed in species with minimal nest types; (2) increased breeding season temperatures were linked to reduced nestling survival; and (3) greater breeding season precipitation negatively affected nestling survival. These results highlight important effects of weather and climate on components of avian reproduction, while also revealing the complexity and context-dependent nature of these influences, emphasizing the need for conservation strategies that account for shifts in weather and climate.

Bird–window collisions are a top source of direct anthropogenic mortality for birds worldwide. Although there are many commercially available products designed to reduce bird–window collisions, relatively few studies have included replicated field testing of such products to assess their effectiveness in real-world environments. We conducted a field study testing the effectiveness of Feather Friendly® white-dot window markers (5.1 × 5.1 cm-spaced, on the exterior) in reducing bird collisions at 2 buildings (6 total building façades) that were treated with the markers in comparison to several untreated buildings on the campus of Oklahoma State University in Stillwater, Oklahoma, USA. We included a before-after control-impact (BACI) design to evaluate collision rates at both treated and untreated buildings before and after the window markers were applied to the 6 glass façades in June 2023. Descriptive estimates based on collision data indicate that collision rates at treated façades were reduced by 67.2–71.6% in the post-treatment period compared to the pre-treatment period. We observed this reduction despite a 15.7% increase in collision rates at untreated façades from the pre-treatment to post-treatment periods. Although the formal BACI analysis found no significant effect of the interaction between treatment (treated versus untreated building façades) and period (pre- versus post-treatment periods), the above descriptive pattern suggests that this result may have been related to limited statistical power associated with the low replication of treated façades. Our results provide additional evidence indicating the effectiveness of this type of window marker in reducing bird collisions. Additionally, this study showcases a rigorous framework for conducting field tests of bird–window collision deterrent products that can be used for future evaluations of the effectiveness of similar products in real-world situations.

Woody plant encroachment is one of the largest threats to grasslands of the US Great Plains. Its spread, mainly due to fire suppression, affects entire ecosystems, including arthropod vectors, bird communities, and the ecology of vector-borne disease. Eastern redcedar (Juniperus virginiana), one of the primary encroaching species in this region, is known to increase abundance of pathogen-carrying tick species such as Amblyomma americanum; however, the role birds play in carrying ticks in association with eastern redcedar encroachment is unknown. In areas of Oklahoma representing 3 stages of eastern redcedar encroachment, we mist-netted birds, sampled larval and nymphal ticks from them, and evaluated tick infestation of birds from May to October 2023. Of 140 birds sampled, 25.7% were infested with ticks, a higher prevalence of infestation than in most previous studies of birds in the United States. Notably, some birds were infested with Ixodes scapularis, which has rarely been found on wildlife other than reptiles in the southern US. There were no significant differences in prevalence or intensity of tick infestation in birds across differing levels of eastern redcedar encroachment, indicating that a high proportion of birds carry ticks in all encroachment stages. This study provides the first evidence that birds contribute to the ecology of tick-borne disease systems in grasslands experiencing woody plant encroachment. Our results, which suggest birds are likely moving ticks into, out of, and among eastern redcedar-encroached grasslands of the US Great Plains, can help inform land management and public health efforts seeking to reduce disease risk.

As the incidence of tick-borne disease expands globally, comprehensive understanding of pathogen reservoir hosts is crucial to protect humans and wildlife. While many components are understood, there are gaps in our knowledge regarding the role of alternative, non-mammalian hosts such as birds. Within the United States, birds have been identified as reservoirs for Borrelia and Rickettsia; however, local studies rarely examine the potential of birds as reservoirs and transporters of Ehrlichia-infected ticks, unlike studies in Europe and South America. To address this research gap, we extracted and sequenced important microorganisms within 90 larval and nymphal ticks which were removed from passerine and near-passerine birds in the Great Plains region of the United States between May and October 2023. We found that 11% of birds hosted ticks infected with one or more Rickettsia or Ehrlichia species. Additionally, we collected a larval Haemaphysalis leporispalustris infected with Ehrlichia chaffeensis from a Northern Cardinal, the first North American songbird implicated in the Ehrlichia transmission cycle. Our research intertwines multiple bird and tick species in the North American pathogen system, highlighting the need for continued research focusing on birds as tick hosts and pathogen reservoirs in understudied parts of the United States.

Understanding the relationship between biodiversity and ecological stability is increasingly urgent as rapid species extinction continues. Though evidence of positive diversity–stability relationships is accumulating, empirical results are inconsistent, and effect sizes tend to be small, raising questions about relative contributions of intrinsic (i.e., species composition/interactions) and extrinsic (i.e., environmental) drivers of stability. Community stability may be more strongly influenced by environmental conditions than by community diversity in some contexts, yet little is known about the comparative importance of diversity and climate means, extremes, and variability in regulating stability. We used a half‐century of continental‐scale bird data to quantify avian community temporal variability (a metric often used to approximate ecological stability) at 1379 sites and compared relative effects of climatic variables and species richness. We found that extreme heat and extremely low precipitation at decadal scales are associated with high bird community variability and these climate variables outperformed species richness in terms of variance explained and magnitude of effect. This provides empirical support for the theoretical concept that, at a continental, decadal scale, environmental conditions can play a larger role than intrinsic factors in determining community stability. Our findings also increase understanding of how climate extremes cause diverse ecological responses.

The green-up of vegetation in spring brings a pulse of food resources that many animals track during migration. However, green-up phenology is changing with climate change, posing an immense challenge for species that time their migrations to coincide with these resource pulses. We evaluated changes in green-up phenology from 2002 to 2021 in relation to the migrations of 150 Western-Hemisphere bird species using eBird citizen science data. We found that green-up phenology has changed within bird migration routes, and yet the migrations of most species align more closely with long-term averages of green-up than with current conditions. Changing green-up strongly influenced phenological mismatches, especially for longer-distance migrants. These results reveal that bird migration may have limited flexibility to adjust to changing vegetation phenology and emphasize the mounting challenge migratory animals face in following en route resources in a changing climate.

Bird populations are declining globally. Wind and solar energy can reduce emissions of fossil fuels that drive anthropogenic climate change, yet renewable‐energy production represents a potential threat to bird species. Surveys to assess potential effects at renewable‐energy facilities are exclusively local, and the geographic extent encompassed by birds killed at these facilities is largely unknown, which creates challenges for minimizing and mitigating the population‐level and cumulative effects of these fatalities. We performed geospatial analyses of stable hydrogen isotope data obtained from feathers of 871 individuals of 24 bird species found dead at solar‐ and wind‐energy facilities in California (USA). Most species had individuals with a mix of origins, ranging from 23% to 98% nonlocal. Mean minimum distances to areas of likely origin for nonlocal individuals were as close as 97 to >1250 km, and these minimum distances were larger for species found at solar‐energy facilities in deserts than at wind‐energy facilities in grasslands (Cohen's d = 6.5). Fatalities were drawn from an estimated 30–100% of species’ desingated ranges, and this percentage was significantly smaller for species with large ranges found at wind facilities (Pearson's r = −0.67). Temporal patterns in the geographic origin of fatalities suggested that migratory movements and nonmigratory movements, such as dispersal and nomadism, influence exposure to fatality risk for these birds. Our results illustrate the power of using stable isotope data to assess the geographic extent of renewable‐energy fatalities on birds. As the buildout of renewable‐energy facilities continues, accurate assessment of the geographic footprint of wildlife fatalities can be used to inform compensatory mitigation for their population‐level and cumulative effects.