bluuebunny/crossref_metadata_2025_split huggingface dataset:
Speciation despite gene flow in two owls (Aegolius ssp.): Evidence from 2,517 ultraconserved element loci
Authors: Winker Kevin , Glenn Travis C , Withrow Jack , Sealy Spencer G , Faircloth Brant C 
Published: July 2019

AbstractNew study systems and tools are needed to understand how divergence and speciation occur between lineages with gene flow. Migratory birds often exhibit divergence despite seasonal migration, which brings populations into contact with one another. We studied divergence between 2 subspecies of Northern Saw-whet Owl (Aegolius acadicus), in which a sedentary population on the islands of Haida Gwaii, British Columbia (A. a. brooksi), exists in the presence of the other form (A. a. acadicus) during migration but not during the breeding season. Prior research showed fixed mtDNA divergence but left open the question of nuclear gene flow. We used 2,517 ultraconserved element loci to examine the demographic history of this young taxon pair. Although we did not observe fixed single nucleotide polymorphism differences between populations among our genotyped individuals, 100% of the birds were diagnosable and δaδI analyses suggested the demographic model best fitting the data was one of split-bidirectional-migration (i.e. speciation with gene flow). We dated the split between brooksi and acadicus to ~278 Kya, and our analyses suggested gene flow between groups was skewed, with ~0.7 individuals per generation coming from acadicus into brooksi and ~4.4 going the opposite direction. Coupled with an absence of evidence of phenotypic hybrids and the birds’ natural history, these data suggest brooksi may be a young biological species arising despite historic gene flow.
Ecological and social correlates of natal dispersal in female and male Thorn-tailed Rayadito (Aphrastura spinicauda) in a naturally isolated and fragmented habitat
Authors: Botero-Delgadillo Esteban , Quirici Verónica , Poblete Yanina , Cuevas Élfego , Kuhn Sylvia , Girg Alexander , Poulin Elie , Kempenaers Bart , Vásquez Rodrigo A 
Published: July 2019

AbstractSex-biased natal dispersal is predicted to be a consequence of differences in the costs and benefits of dispersal perceived by each sex. Although female-biased dispersal has been described for numerous birds in heterogeneous landscapes, studies documenting sex-related differences in the causes and consequences of natal dispersal in fragmented habitats are comparatively scarce. We used capture-mark-recapture data and genetic analyses in a population of Thorntailed Rayadito (Aphrastura spinicauda) from north-central Chile in order to investigate how the possible causes and consequences of dispersal are linked to sex-specific dispersal behavior in a naturally isolated and fragmented forest habitat. We analyzed 36 recaptured post-fledging birds to test whether female-biased dispersal reflected differential responses between sexes to potentially long-term acting selective pressures related to habitat fragmentation and high population densities. In this population, females disperse long distances (median distance: 780 m), whereas males are mostly philopatric (median distance: 85 m). Results suggest that female dispersal is possibly a response to the local density of breeding birds and mate availability, and comes without apparent reproductive costs. Inbreeding avoidance was not evident, but females may already be decreasing the probability of mating with relatives by moving away from their natal neighborhood where male kin usually remain. Our findings also indicate that male dispersal, while reduced in relation to females, can result from a tradeoff between the social benefits of settling near the natal territory and the associated costs of high breeding densities and kin competition. An increase of paternity loss was evident for males moving long distances. Follow-up studies should assess the differences in the costs and benefits of within- and between-fragment dispersal in this population.
Landscape context matters when American Woodcock select singing grounds: Results from a reciprocal transplant experiment
Authors: Brenner Stephen J , Buffum Bill , Tefft Brian C , McWilliams Scott R 
Published: July 2019

AbstractThe multiscale nature of habitat selection during the breeding season for migratory birds means that core-use areas (e.g., breeding territories) are selected based on their local habitat features, but these may also be influenced in some way by features within a larger-scale landscape. We conducted a reciprocal transplant experiment to test the hypothesis that habitat selection and movements of male American Woodcock (Scolopax minor) in core-use areas during the breeding season depend on the perceived quality of the surrounding landscape. We captured second-year male woodcocks (n = 19) at high- or low-likelihood of use landscapes in Rhode Island, USA, affixed each with a radio transmitter, relocated them to the opposite type of landscape, and then determined if they returned to their original site of capture or remained in the landscape to which they were relocated. Birds captured in high-likelihood landscapes and moved to low-likelihood landscapes generally returned to their original high-likelihood landscape (5/7, 71%), but birds captured in low-likelihood landscapes and moved to high-likelihood landscapes rarely returned to their original low-likelihood landscape (1/12, 8%). These results support the hypothesis that woodcock assess their surroundings relatively rapidly and subsequently make critical settlement decisions based on landscape composition. Given that woodcock choice is predicted by the woodcock-specific resource selection function, these results also provide support for the use of this tool to guide forest management for woodcock.
Phantom interactions: Use odds ratios or risk misinterpreting occupancy models
Authors: Jones Gavin M , Peery M Zachariah 
Published: July 2019

AbstractOccupancy models rely on logistic regression approaches that use the logit link function for model fitting. Parameter estimates fitted on the logit scale are frequently back-transformed to the probability scale for interpretation. However, caution is necessary, because back-transformation from the linear logit scale to the bounded probability scale can yield statistical artifacts that could lead to spurious inferences. We discuss one such artifact that we term “phantom interactions”—that is, apparent but false interactions—where the effect size of an additive model parameter, when interpreted on the probability scale, appears to vary depending on the value of other model covariates. A recent paper published in The Condor: Ornithological Applications provides an example of this issue (Lee and Bond 2015). The paper’s title and central conclusion state that estimated negative effects of fire and salvage logging on Spotted Owl (Strix occidentalis) site occupancy were large at sites where reproduction did not occur the previous year, but small (or “negligible”) at sites where reproduction did occur the previous year, suggesting breeding owls were resistant to disturbances. This implies the explicit modeling of a breeding state × disturbance interaction, but no interactive effects were present in the model used by the authors. A simple calculation of odds ratios (ORs) using data from the paper shows the modeled effects of fire and salvage logging on owls were, in fact, equivalent regardless of the previous year’s reproductive state. Lee and Bond (2015) incorrectly concluded differential effects of fire and salvage logging on breeding versus nonbreeding owls because the effect for breeding owls occurred near a boundary on the probability scale, where a change on the logit corresponded to very small changes in probability. To avoid problematic inference, researchers should use ORs to interpret logistic regression and occupancy models.
Nesting near road edges improves nest success and post-fledging survival of White-rumped Shamas (Copsychus malabaricus) in northeastern Thailand
Authors: Angkaew Rongrong , Sankamethawee Wangworn , Pierce Andrew J , Savini Tommaso , Gale George A 
Published: July 2019

ABSTRACT
Road edges in the temperate zone often negatively affect reproductive success, post-fledging survival, and dispersal of forest birds through processes associated with edge habitats. This pattern is less clear in the tropics due to a lack of studies using natural nests and radio-tagged fledglings as well as an almost complete absence of information on nest and fledgling predators. We investigated the influence of road edge on nest success, post-fledging survival, and dispersal of White-rumped Shama (Copsychus malabaricus) in a dry evergreen forest in northeastern Thailand. One hundred nest boxes were placed in forest interior (≥1,000 m from edge of a 5-lane highway) and 100 near forest edge (≤200 m) to assess nesting success. We radio-tracked 50 fledglings from these boxes, 25 each for edge and interior, for 7 weeks after fledging. Nest success and post-fledging survival were 11.6% and 23.6% higher at the edge versus the interior. Predation had the strongest influence on survival, accounting for 100% of nest and 94% of fledgling mortality. Fledglings used locations with denser understory vegetation cover relative to the available habitat, probably to reduce predation risk. Green cat snake (Boiga cyanea) and northern pig-tailed macaque (Macaca leonina), which likely prefer forest interiors over edges, were the primary predators of nests and fledglings in this landscape. There were no significant differences in timing of dispersal and dispersal distance or dispersal direction in relation to proximity to edge. Our results suggest that the impacts of edge effects on the reproductive success of birds appear to be strongly dependent on the habitat preferences of locally dominant predators. Further research will be needed to identify key predators and broadly assess their foraging behaviors in individual landscapes.
Using web-sourced photography to explore the diet of a declining African raptor, the Martial Eagle (Polemaetus bellicosus)
Authors: Naude Vincent N , Smyth Lucy K , Weideman Eleanor A , Krochuk Billi A , Amar Arjun 
Published: July 2019

ABSTRACTUnderstanding a species’ diet can be critical for effective conservation. While several traditional methods for assessing raptor diet exist, many pose inherit biases and often require extensive fieldwork that can limit sample sizes and the geographic scope of studies. This is especially true for species that nest at low densities (e.g., large eagles). Recently, several studies have demonstrated the value of web-sourced photographs in tackling ecological and evolutionary questions. Specialized software (e.g., MORPHIC) has been developed to systematically extract Google Images for this purpose. We used this approach to explore the diet of Martial Eagles (Polemaetus bellicosus). A shortage of prey is one of the proposed hypotheses for recent population declines across their range. Of the 4,872 photographs selected by MORPHIC, 254 were usable (5%). Birds, mammals, and reptiles each contributed similarly to overall identified prey. Helmeted Guineafowl (Numida meleagris) were the most important bird prey identified (12% of overall prey). The 4 most important mammalian prey species were Thompson’s gazelle (Eudorcas thomsonii; 5%), impala (Aepyceros melampus; 4%), common duiker (Sylvicapra grimmia; 4%), and banded mongoose (Mungos mungo; 4%). Reptile prey was dominated by monitor lizards (Varanus spp.; 21%). Prey class proportions differed significantly by regions with mammalian prey being more common in eastern Africa and reptile prey being more common in southern Africa. Within South Africa, reptile prey proportion was greater in the east than in the west. These corroborate existing prey composition studies. Prey composition differed between age classes, with adult eagles preying on more birds than non-adults. There was no significant difference in the average estimated prey weight by eagle age or feeding position (ground, perched, or flying). Our results suggest that this approach may offer a useful method to explore the diet for raptor species that are well photographed across their range, at minimal cost and research effort.
Effects of individual misidentification on estimates of survival in long-term mark–resight studies
Authors: Tucker Anna M , McGowan Conor P , Robinson Robert A , Clark Jacquie A , Lyons James E , DeRose-Wilson Audrey , Du Feu Richard , Austin Graham E , Atkinson Philip W , Clark Nigel A 
Published: July 2019

Abstract
All ecological measurements are subject to error; the effects of missed detection (false negatives) are well known, but the effects of mistaken detection (false positives) are less understood. Long-term capture–recapture datasets provide valuable ecological insights and baselines for conservation and management, but where such studies rely on noninvasive re-encounters, such as field-readable color bands, there is the potential to accumulate detection errors as the length of the study and number of tags deployed increases. We investigated the prevalence and effects of misreads in a 10-yr dataset of Red Knots (Calidris canutus rufa) marked with field-readable leg flags in Delaware, USA. We quantified the effects of misreads on survival estimation via a simulation study and evaluated whether removal of individuals only reported once in a year (potential misreads) influenced survival estimation from both simulated datasets and our case study data. We found overall apparent error rates of 0.31% (minimum) to 6.6% (maximum). Observer-specific error rates and the variation among observers both decreased with the number of flags an observer recorded. Our simulation study showed that misreads lead to spurious negative trends in survival over time, particularly for long-term studies. Removing all records in which a flag was only recorded once in a sampling occasion reduced bias and eliminated spurious negative trends in survival but also reduced precision in survival estimates. Without data filtering, we found a slight decrease in Red Knot annual survival probability from 2008 to 2018 (β = −0.043 ± 0.03), but removing all single-observation records resulted in no apparent trend (β = −0.0074 ± 0.02). Spurious trends in demographic rates could influence inference about population trajectories and resultant conservation decision-making. Data filtering could eliminate errors, but researchers should carefully consider the tradeoff between precision obtained by larger sample sizes and potential bias due to misreads in their data.
The importance of disturbance and forest structure to bird abundance in the Black Hills
Authors: Matseur Elizabeth A , Millspaugh Joshua J , Thompson Frank R , Dickerson Brian E , Rumble Mark A 
Published: July 2019

AbstractMany North American birds associated with forest disturbances such as wildfire and mountain pine beetle (Dendroctonus ponderosae) outbreaks are declining in abundance. More information on relationships between avian abundance and forest structure and disturbance is needed to guide conservation and management. Our objective was to determine densities of American Three-toed Woodpecker (Picoides dorsalis), Black-backed Woodpecker (Picoides arcticus), Red-breasted Nuthatch (Sitta canadensis), Brown Creeper (Certhia americana), and White-winged Junco (Junco hyemalis aikeni) in relation to vegetation characteristics and disturbance at the point and landscape level in the Black Hills and Bear Lodge Mountains of South Dakota and Wyoming. We conducted 3 point counts from late March to late June 2015 and 2016 at more than 2,300 locations distributed across a gradient of forest structure and disturbance types. We estimated densities using 3-level hierarchical time-removal models that simultaneously estimated abundance, availability, and detection probability. Black-backed Woodpeckers were positively related to percent area in 1- to 3-year-old wildfires and Brown Creepers were positively associated with percent area in 4- to 5-year-old wildfires; however, Red-breasted Nuthatches were negatively related to percent area in 3- to 5-year-old wildfires. With the exception of American Three-toed Woodpeckers, species were positively related to percent cover of beetle-killed trees. Brown Creepers, White-winged Juncos, and Red-breasted Nuthatches had mixed responses to percent overstory canopy cover. White-winged Juncos also had a positive association with percent ground vegetation at the point and landscape level. Brown Creepers were strongly linked with spruce vegetation type. American Three-toed Woodpeckers, which are thought to occupy spruce forest in the Black Hills, did not show a strong relationship with any covariates. Maintaining some areas of natural disturbances along with heterogeneity of vegetation characteristics within stands and at the landscape scale will benefit the needs of a diverse bird community in the Black Hills.
No evidence of a demographic response to experimental herbicide treatments by the White-crowned Sparrow, an early successional forest songbird
Authors: Rivers James W , Verschuyl Jake , Schwarz Carl J , Kroll Andrew J , Betts Matthew G 
Published: July 2019

AbstractEarly-successional forest birds, which depend on disturbance events within forested landscapes, have received increased conservation concern because of long-term population declines. Herbicides are often used to control vegetation within early-successional forests, with unknown effects on avian vital rates. We used a large-scale experiment to test how nest and post-fledging survival were influenced by herbicide intensity within managed conifer plantations across 2 breeding seasons. We created a gradient of 4 stand-scale herbicide treatments (light, moderate, and intensive, and no-spray control) and evaluated the reproductive response of the White-crowned Sparrow (Zonotrichia leucophrys), a declining songbird in managed forest landscapes of the Pacific Northwest. Against initial predictions, we found no evidence that either daily nest survival (n &gt; 760 nests across all treatments) or post-fledging survival (n = 70 individuals reared in control and moderate treatments) were influenced by herbicide application intensity. Increased herbicide intensity resulted in an extensive reduction in vegetation cover at both stand and nest-patch scales; in contrast, vegetative cover at nest sites did not differ across herbicide treatments, nor was nest survival related to vegetation concealment measures. As the largest experimental investigation to assess forest herbicide effects on songbird demography, our study indicates that components of sparrow reproductive success were not influenced by experimental vegetation control measures, although additional work on other early-successional species will be useful to evaluate the generalities of our findings.
Near-ultraviolet light reduced Sandhill Crane collisions with a power line by 98%
Authors: Dwyer James F , Pandey Arun K , McHale Laura A , Harness Richard E 
Published: July 2019

Abstract
Midflight collisions with power lines impact 12 of the world’s 15 crane species, including 1 critically endangered species, 3 endangered species, and 5 vulnerable species. Power lines can be fitted with line markers to increase the visibility of wires to reduce collisions, but collisions can persist on marked power lines. For example, hundreds of Sandhill Cranes (Antigone canadensis) die annually in collisions with marked power lines at the Iain Nicolson Audubon Center at Rowe Sanctuary (Rowe), a major migratory stopover location near Gibbon, Nebraska. Mitigation success has been limited because most collisions occur nocturnally when line markers are least visible, even though roughly half the line markers present include glow-in-the-dark stickers. To evaluate an alternative mitigation strategy at Rowe, we used a randomized design to test collision mitigation effects of a pole-mounted near-ultraviolet light (UV-A; 380–395 nm) Avian Collision Avoidance System (ACAS) to illuminate a 258-m power line span crossing the Central Platte River. We observed 48 Sandhill Crane collisions and 217 dangerous flights of Sandhill Crane flocks during 19 nights when the ACAS was off, but just 1 collision and 39 dangerous flights during 19 nights when the ACAS was on. Thus, we documented a 98% decrease in collisions and an 82% decrease in dangerous flights when the ACAS was on. We also found a 32% decrease in the number of evasive maneuvers initiated within 25 m of the power line along the river, and a 71% increase in the number of evasive maneuvers initiated beyond 25 m when the ACAS was on. Sandhill Cranes reacted sooner and with more control, and experienced substantially fewer collisions, when the ACAS was on. Installation of the ACAS on other high-risk spans, and perhaps on other anthropogenic obstacles where birds collide, may offer a new solution to a long-running conservation dilemma.
Effects of climate change on the distributional potential of three range-restricted West African bird species
Authors: Freeman Benedictus , Sunnarborg Julia , Peterson A Townsend 
Published: July 2019

AbstractA detailed understanding of species’ responses to global climate change provides an informative baseline for designing conservation strategies to optimize protection of biodiversity. However, such information is either limited or not available for many tropical species, making it difficult to incorporate climate change into conservation planning for most tropical species. Here, we used correlative ecological niche models to assess potential distributional responses of 3 range-restricted West African birds, Timneh Parrot (Pscittacus erithracus timneh), Ballman’s Malimbe (Malimbus ballmanni), and White-necked Rockfowl (Picathartes gymnocephalus), to global climate change. We used primary biodiversity occurrence records for each species obtained from the Global Biodiversity Information Facility, eBird, and VertNet; for environmental data, we used climatic variables for the present and future, the latter characterized by 2 IPCC representative concentration pathways (4.5, 8.5) future emissions scenarios and 27 general circulation models for a 2050 time horizon. We found broad present-day potential distributions with respect to climate for all 3 species. Future potential distributions for Ballman’s Malimbe and White-necked Rockfowl tended to be stable and closely similar to their present-day distributions; by contrast, we found marked climate change–driven potential range loss across the range of Timneh Parrot. Our results suggest that impacts of climate change on the present distributions of West African birds will in some cases be minimal, but that individual species may respond differently to future conditions. Thus, to optimize conservation of these species, and of bird diversity in general, we recommend that regional-to-national species conservation action plans incorporate climate change adaptation strategies for individual species; ecological niche models could provide an informative baseline information for this planning and prioritization.