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The nests of ground‐nesting birds rely heavily on camouflage for their survival, and predation risk, often linked to ecological changes from human activity, is a major source of mortality. Numerous ground‐nesting bird populations are in decline, so understanding the effects of camouflage on their nesting behavior is relevant to their conservation concerns. Habitat three‐dimensional (3D) geometry, together with predator visual abilities, viewing distance, and viewing angle, determine whether a nest is either visible, occluded, or too far away to detect. While this link is intuitive, few studies have investigated how fine‐scale geometry is likely to help defend nests from different predator guilds. We quantified nest visibility based on 3D occlusion, camouflage, and predator visual modeling in northern lapwings, Vanellus vanellus, on different land management regimes. Lapwings selected local backgrounds that had a higher 3D complexity at a spatial scale greater than their entire clutches compared to local control sites. Importantly, our findings show that habitat geometry—rather than predator visual acuity—restricts nest visibility for terrestrial predators and that their field habitats, perceived by humans as open, are functionally closed with respect to a terrestrial predator searching for nests on the ground. Taken together with lapwings' careful nest site selection, our findings highlight the importance of considering habitat geometry for understanding the evolutionary ecology and management of conservation sites for ground‐nesting birds. We used 3D scanning and color‐calibrated images to investigate the effects of local geometry on ground‐nesting bird site selection and camouflage. We found that lapwings, Vanellus vanellus, locally select for more 3D variable areas and that the scale and shape of their nests restrict visibility more than predator visual acuity, with crop fields and wet grassland acting more like a closed habitat from the viewing angles of natural predators.

Comparative studies of egg recognition and rejection between various sympatric hosts provide insight into the coevolutionary history of the hosts and parasites, as well as the degree of antagonism between the species. Although buntings are widely considered to be a suitable host taxon for cuckoos, there has been relatively little research on this example of parasitism and host antiparasitic behaviour. Here we provided the first report on brood parasitism and egg recognition in three sympatric ground‐nesting bunting hosts of the common cuckoo ( Cuculus canorus ), namely the yellow‐throated bunting ( Emberiza elegans ), south rock bunting ( E. yunnanensis ), and crested bunting ( E. lathami ). The results show that for the five breeding seasons during 2018–2022, the parasitism rate by common cuckoos was 0.87% and 0.45% in yellow‐throated buntings and south rock buntings, respectively, whereas the parasitism rate by an unidentified parasite was 4% during 2018–2023 in the crested bunting. The rejection rates of the three bunting hosts for blue non‐mimetic eggs were 89.3%, 88.9%, and 100% for yellow‐throated buntings, south rock buntings, and crested buntings, respectively. The rejection rates for red non‐mimetic eggs by yellow‐throated buntings and south rock buntings were lower at 76.9% and 82.4%, respectively. All three sympatric bunting hosts examined had high levels of egg recognition and egg rejection, suggesting that it may have been subjected to high parasitic history and that egg recognition ability was retained after the loss of parasitism, which needs to be further verified by future experiments.

ABSTRACT Peatland ecosystems and the unique biodiversity they support are under risk from multiple stressors, including changes in species interactions. Land use changes that lead to increases in the density and activity of mammalian mesopredators such as red fox (Vulpes vulpes) and pine marten (Martes martes) could be particularly detrimental to vulnerable peatland species such as wading birds (Chardiiformes). However, our understanding of predator–prey interactions in the context of land use change remains limited, because most published evidence is correlative. In contrast, DNA metabarcoding of scats can reliably identify both the host and the prey consumed, thereby clarifying the role of consumption in species interactions. In this study, we collected scats from areas of open peatland and non‐native forestry on peatland across the Forsinard Flows Nature Reserve, part of The Flow Country UNESCO World Heritage Site in Scotland. We focused our collections during the wader breeding season of 2023. Following DNA extraction and metabarcoding, we found that diets of foxes and pine marten were made up of small mammals (e.g., Rodentia and Soricidae), non‐wader bird species, and frogs. By frequency of occurrence, birds formed a substantial part of the pine marten diet (50%), while red deer carrion and pine marten (or their scat) were key food resources for foxes (46% and 50% respectively). Surprisingly, wading birds were absent from our samples, challenging the assumption that forest‐associated mammalian predators actually prey on waders in adjacent peatland. DNA metabarcoding may be crucial to understanding the trophic and non‐trophic interactions that govern recruitment and habitat use of vulnerable native species in remote and complex landscapes. DNA metabarcoding of predator scat can provide direct evidence of trophic interactions in a landscape that may refute prior indirect evidence based on correlative data.

Nest defense behavior helps ground‐nesting birds improve their breeding success. Among such behaviors, injury feigning behavior (IFB) is one of the better ways to attract predators and protect birds' nests. IFB is generally associated with shorebirds in general and plovers in particular, however, through field observation, it has been found this behavior is also exhibited in bunting species when they facing the risk of predation. We attempt to explore the detailed description of this behavior in buntings and the factors that affect this behavior. Based on video‐recordings of the nest defense behavior by the ground‐nesting bird Godlewski's bunting (Emberiza godlewskii) against nest invaders, we explored the characteristic of IFB and differences in nest defense behavior during their brooding seasons. The results showed that female buntings had a distinct IFB: the wings of buntings incited within 60°–90° of the body, ran and called rapidly, pretending to be injured and unable to fly. The nest stage had significant and extremely significant effects on IFB and movement distance (MD), respectively. And IFB was more likely to occur in brooding (34.62%) than incubation period (16.42%). This indicates that there are significant differences in the IFB of buntings at different breeding stages. Based on video‐recordings of the nest defense behavior by the ground‐nesting bird Godlewskiʼs bunting (Emberiza godlewskii) against nest invaders, we explored the characteristic of IFB and differences in nest defense behavior during their brooding seasons. The results showed that female buntings had a distinct IFB: the wings of buntings incited within 60°–90° of the body, ran and called rapidly, pretending to be injured and unable to fly.

ABSTRACT Environmental DNA (eDNA) has transformed biodiversity monitoring, especially in aquatic environments; yet, its application in terrestrial habitats remains limited. In arid regions, artificial waterbodies, such as farm dams and water troughs, serve as essential resources for wildlife and offer a promising but underutilised opportunity for eDNA‐based detection. Here, we designed and validated a highly sensitive, species‐specific quantitative PCR (qPCR) assay to detect the nationally threatened southern squatter pigeon (Geophaps scripta scripta). We validated the qPCR assay in the field by successfully detecting the target species at extremely low DNA concentrations (1 × 10−7 ng/μL; r2 = 0.992) using both active syringe and passive filtration methods across multiple farm dams and water troughs on a 20,000‐ha cattle property in northern Australia. To complement eDNA analysis, we also undertook standardised 20‐min, 2‐ha bird surveys at these sites. Positive detections were recorded at both trough and dam sites during the austral tropical dry season. Notably, whilst eDNA detections and visual bird counts aligned in terms of the number of occupied sites, their exact locations did not always coincide, highlighting the complementary nature of these two monitoring techniques. This assay represents a significant advancement in the conservation of this threatened ground‐nesting species, demonstrating that eDNA sampling at artificial waterpoints is a viable tool for monitoring terrestrial fauna in remote, semi‐arid landscapes.

1. Nesting birds can be vulnerable to predation. Wildlife managers sometimes manipulate predator communities to enhance avian productivity and abundance. Managers need to know the predation risk from different predator species responsible for nest failures to maximize success. This issue is especially important when considering reductions in only a part of the predator community in complex ecosystems. 2. We conducted a 7-year crossover experiment at four study sites to examine the effect of mesomammalian predator control on nest success of northern bobwhite Colinus virginianus in the southeastern USA. Nests were monitored using 24-h near-infrared video. We hypothesized that nest failures caused by different predator guilds may not be independent and may lead to compensation by other predators as one predator guild was reduced. 3. We compared levels of bobwhite nest predation by mesomammals, snakes and other predators in years with and without mesomammal control. 4. Control of mesomammal predators reduced the levels of mesomammal nest predation, but predation levels by snakes and other predators increased such that total nest mortality was not reduced. Nest mortality among predator groups was best described as compensatory, and total nest mortality differed among sites. 5. Synthesis and applications. Our findings suggest that reductions in predation risk from one predator guild can be compensated by an increased risk from other predators in complex ecosystems. Predator removal within one group may not translate to additive increases in overall nest success, but rather results in shifts in the identity of predators responsible for nest failures. Management efforts focused on manipulating predator communities to enhance avian reproduction are encouraged to examine cause-specific nest fates to determine the effectiveness of predator reduction programmes.

Repeated prescribed fire can create and maintain areas with sparse overstory tree cover and a dense grass-forb-shrub understory, providing habitat for northern bobwhite (Colinus virginianus; hereafter, bobwhite). Despite potential benefits of prescribed fires for conserving bobwhite habitat, burning during the nesting season may destroy bobwhite nests and reduce available nesting cover. We monitored radio-transmittered bobwhite (n = 104) from 2016 to 2018 to describe nest-site selection and determine the risk of nest destruction on a 17,000-ha North Carolina military installation, Fort Bragg, managed with rotational growing-season and dormant-season prescribed fires on an approximate 3-year return interval. We located 48 nests, of which 8 (16%) were in areas burned the same year, 9 (19%) were in one-year post fire, 25 (52%) were in 2-years post fire, and 6 (13%) were in ≥3-years post fire areas. We compared vegetation composition and structure at nests to nearby random locations and determined bobwhite selected nest sites with greater woody understory and wiregrass cover, lower basal areas of pines and hardwoods, and less distance to the nearest road. Two nests (6.7%) were destroyed during prescribed fires, but success of incubated nests was high (67%). We calculated the overall risk of nest destruction by prescribed fire as the proportion of active nests in areas with ≥3 years since last fire multiplied by the proportion of the study area burned each week. Overall, 11% (weekly x̄ = 0.75%, range = 0–3%) of the study area was burned during the 2016 nesting season (3 June to 3 September), 4% (weekly x̄ = 0.31%, range 0–2%) of the study area was burned during the 2017 nesting season (5 June to 2 September), and 7.5% (weekly x̄ = 0.58%, range 0–5%) of the study area was burned during the 2018 nesting season (3 June to 31 August). We estimated that no more than 0.75% of bobwhite nests across the study site were exposed to fire annually. Most growing-season fires occurred before the bobwhite nesting season, which limited direct effects of prescribed fire on bobwhite nest survival. However, shifting prescribed fires to later in the growing season to better match the historical lightning season (i.e., after 1 June) would increase the risk of nest destruction. Because bobwhite used older roughs (i.e. areas 2 years since fire) for nesting, shortening the fire return interval to less than 3 years would increase the proportion of nests exposed to fire. Additionally, a shortened fire return interval would decrease available nesting cover, especially in regions with low soil fertility where vegetation change following fire is less rapid than on more productive soils.

Ground‐nesting farmland birds such as the grey partridge (Perdix perdix) have been rapidly declining due to a combination of habitat loss, food shortage, and predation. Predator activity is the least understood factor, especially its modulation by landscape composition and complexity. An important question is whether agri‐environment schemes such as flower strips are potentially useful for reducing predation risk, for example, from red fox (Vulpes vulpes). We employed 120 camera traps for two summers in an agricultural landscape in Central Germany to record predator activity (i.e., the number of predator captures) as a proxy for predation risk and used generalized linear mixed models (GLMMs) to investigate how the surrounding landscape affects predator activity in different vegetation types (flower strips, hedges, field margins, winter cereal, and rapeseed fields). Additionally, we used 48 cameras to study the distribution of predator captures within flower strips. Vegetation type was the most important factor determining the number of predator captures and capture rates in flower strips were lower than in hedges or field margins. Red fox capture rates were the highest of all predators in every vegetation type, confirming their importance as a predator for ground‐nesting birds. The number of fox captures increased with woodland area and decreased with structural richness and distance to settlements. In flower strips, capture rates in the center were approximately 9 times lower than at the edge. We conclude that the optimal landscape for ground‐nesting farmland birds seems to be open farmland with broad extensive vegetation elements and a high structural richness. Broad flower blocks provide valuable, comparatively safe nesting habitats, and the predation risk can further be minimized by placing them away from woods and settlements. Our results suggest that adequate landscape management may reduce predation pressure. Red fox in a flower strip. Credit: Amelie Laux.

Disruption of historic fire regimes has led to the expansion of hardwoods into pine savanna ecosystems in the southeastern United States. Management strategies that reduce mature mesophytic oaks in pine savanna that was previously fire suppressed may help restore understory vegetation and positively affect understory birds. Many private lands in the Southeast are managed intentionally for the Northern Bobwhite (Colinus virginianus; hereafter bobwhite), a species with high cultural and economic importance to the region. Mechanical hardwood reduction is used to restore southeastern pine savanna and as a predation management tool to enhance populations of bobwhite although its utility has not been empirically tested. We measured the demographic response of bobwhite to a large‐scale hardwood reduction using a before‐after‐control‐impact (BACI) study replicated at two properties in the Red Hills region of northern Florida, United States, that had a relatively low density of mature, mesophytic hardwoods and were already managed for bobwhite with 2‐year fire return intervals, supplemental feeding, and meso‐mammal control. We monitored reproduction at 561 nests and survival of 1529 adults tracked with radiotelemetry. In treated sites, mean daily nest survival was 0.98 and did not change following hardwood reduction. Reproductive effort declined each year (pre‐ and post‐treatment; 2015–2018) in one treated site and varied relatively little in the other. At both treated sites, weekly adult survival decreased to 0.93–0.94 immediately following the treatment, then increased gradually but did not exceed pretreatment weekly survival (0.98) within 2–3 years following the treatment. Our results suggest hardwood reduction may not benefit bobwhite adult survival or productivity within 2–3 years of application on sites that are already managed intensively with prescribed fire, predator control, and supplemental feeding and that hardwoods in this system may not have direct negative impacts on understory birds. Further study is necessary to determine under what conditions hardwood reduction may be beneficial and whether other metrics such as chick survival or immigration are affected. Our study sites represent typical land management in the Red Hills region, and we believe the inference of this study extends at least to properties with similar management schemes and similar bobwhite population density.

Anthropogenic disturbance may cause birds to flush and relocate, abandon breeding sites, experience increased nest failure, or fledge fewer young. Ground-based military activities are of particular concern for ground-nesting birds because of the increased risk of nest destruction and trampling of vegetation. We investigated how different intensities of disturbance from ground-based military training affected reproductive ecology of Bachman’s sparrow (Peucaea aestivalis) from 2014–2016, on Fort Bragg Military Installation, North Carolina, USA. We designated 2 training intensity regimes and monitored sparrows at 6 observation areas, 3 in high-intensity training areas (i.e., foot traffic every 1–3 days) and 3 in low-intensity training (i.e., foot traffic <1 per month) areas. We compared seasonal productivity metrics and daily nest survival between training intensities. Additionally, we compared male sparrow relative abundance and micro-habitat use between high- and low-intensity training areas. We monitored 106 male territories and located 110 nests opportunistically and by tracking telemetered female sparrows. We used fixed-radius point counts to estimate relative abundance in each observation area and measured vegetation composition and structure at a subset of 10 locations in each male territory. Seasonal productivity metrics, daily nest survival, relative abundance, and vegetation composition and structure at male locations did not differ between areas with high and low military training intensity. In 2015, 1 sparrow nest was trampled by military personnel, but ≥1 nestling force-fledged and the nest was considered successful. Bachman’s sparrow nesting ecology was not affected by intensity of ground-based military training activity, likely because activity was sufficiently dispersed across the landscape, even in high-intensity training areas. We recommend ground-based training attempts to minimize ground vegetation destruction by dispersing large groups and traversing variable routes when in forested uplands.