Daily Nest Survival Rates Research Articles

Effects of temporal factors, nesting microhabitat and nest position on the survival of passerine nests in a Tunisian oasis habitat

Identifying the ecological factors shaping bird nest survival is essential for understanding bird population dynamics, as well as for conservation purposes. Using data obtained by monitoring natural bird nests in one oasis in south-eastern Tunisia, we fitted logistic exposure models to investigate the effects of nesting microhabitat, nest position and temporal parameters on nest survival rates. Nest age was the most important predictor of daily nest survival rate for the five focal species. However, contrary to many previous studies, daily nest survival rate was positively related to nest age. This finding could be explained by the fact that the main nest predators in Tunisian oases are rodents that are more likely to consume eggs rather than chicks and therefore their impact on bird nests is assumed to be higher during incubation than after hatching. Nesting microhabitat variables and nest position as well as date of nest initiation and year did not significantly affect bird nest survival in the studied oasis. Further studies on the ecology and behaviour of nest predators are needed to more accurately identify the determinants of bird nest survival in the oasis habitat.

Effects of roadside edge on nest predators and nest survival of Asian tropical forest birds

Creation of roadside forest edges can have indirect effects on forest bird communities, as edges can promote species detrimental to forest-nesting birds such as nest predators. We assessed species-specific rates of nest survival of understory birds, relative abundances of specific nest predators and predator-specific rates of nest predation relative to the distance from roadside forest edge in a dry evergreen forest in northeastern Thailand. During the breeding seasons (February–August) of 2014–2016 we searched for nests along two, 1-km transects which ran perpendicular from the edge of a five-lane highway into the forest interior. To assess nest predator species, video cameras were placed on active nests of understory birds and multiple techniques were used to assess the relative abundances of the documented nest predators. We found 306 active nests of 26 species and recorded 179 predation events from 13 species of nest predators. Distance to edge influenced the daily nest survival rates for four of seven focal bird species, with three species having higher survival rates nearer to the edge. Four of six predators had higher relative abundances in the forest interior. Rats and the Common Green Magpie (Cissa chinensis) had higher abundances nearer the edge. Snake detections were too few to assess statistically. Nest predation rates for the top three predators, Northern Pig-tailed Macaque (Macaca leonina), Green Cat Snake (Boiga cyanea) and Crested Goshawk (Accipiter trivirgratus) were significantly greater in the forest interior. The fourth-most important, Common Green Magpie, was the only predator responsible for more nest predation events closer to habitat edge compared to interior. Our study suggests that the impacts of edges on nesting success are highly dependent on the nest predator community and the species-specific responses of predators to edges.

Nest survival in year‐round breeding tropical red‐capped larks Calandrella cinerea increases with higher nest abundance but decreases with higher invertebrate availability and rainfall

Nest survival is critical to breeding in birds and plays an important role in life‐history evolution and population dynamics. Studies evaluating the proximate factors involved in explaining nest survival and the resulting temporal patterns are biased in favor of temperate regions. Yet, such studies are especially pertinent to the tropics, where nest predation rates are typically high and environmental conditions often allow for year‐round breeding. To tease apart the effects of calendar month and year, population‐level breeding activity and environmental conditions, we studied nest survival over a 64‐month period in equatorial, year‐round breeding red‐capped larks Calandrella cinerea in Kenya. We show that daily nest survival rates varied with time, but not in a predictable seasonal fashion among months or consistently among years. We found negative influences of flying invertebrate biomass and rain on nest survival and higher survival of nests when nests were more abundant, which suggests that nest predation resulted from incidental predation. Although an increase in nest predation is often attributed to an increase in nest predators, we suggest that in our study, it may be caused by altered predator activity resulting from increased activity of the primary prey, invertebrates, rather than activity of the red‐capped larks. Our results emphasize the need to conduct more studies in Afro‐tropical regions because proximate mechanisms explaining nest predation can be different in the unpredictable and highly variable environments of the tropics compared with the relatively predictable seasonal changes found in temperate regions. Such studies will aid in better understanding of the environmental influences on life‐history variation and population dynamics in birds.

Radio transmitters did not affect daily nest and chick survival of Piping Plovers (Charadrius melodus)

ABSTRACT Biologists interested in using radio telemetry to track the movements of birds should concurrently conduct studies to assess potential impacts on study organisms, particularly when monitoring threatened or endangered species. We investigated the effects of traditional and digital very high frequency (VHF) radio transmitters on daily nest survival and chick survival rates of Piping Plovers (Charadrius melodus) along the Atlantic Coast in 2012, 2013, and 2015. We attached 1.0–1.2 g transmitters to 110 plovers and monitored their 160 nest attempts. We also monitored 221 nest attempts by 161 control pairs with no transmitters. There was no evidence that nest or chick survival differed between tagged and control pairs. Transmitters did not seem to adversely impact Piping Plover daily nest and chick survival and are a valuable tool to monitor movements of this threatened species.

Sprague's pipit breeding biology and reproductive success in planted and native grasslands

Much of the native grasslands in agricultural regions have been converted to cropland or tilled and seeded with non‐native grasses for livestock production. Several grassland songbird species occupy planted grasslands, but occupancy or density may not be a reliable indicator of habitat quality. I studied the breeding biology of Sprague's pipit Anthus spragueii from 2004 to 2008 in Saskatchewan, Canada. My objective was to determine the extent to which the breeding biology, density and reproductive success of pipits varied in planted and native grasslands. Peak clutch initiation occurred in mid‐ to late‐May in planted and native grassland. Peak pipit density also occurred in May, but density drastically declined over the breeding season in planted grassland. Clutch size varied among years and declined over the breeding season, but was similar in planted (4.7  0.1 SE) and native grasslands (4.5  0.1 SE). Daily nest survival rates varied with age of the nest and date, but the relationships differed in the two habitats and was likely a result of lower nestling survival in planted grassland compared to native grassland. The number of young fledged per nest increased as the season progressed and tended to be greater in native (1.2  0.1 SE) than planted (0.9  0.2 SE) grasslands. Seasonal productivity was much greater in native grassland. Only three nests were initiated after May in planted grassland and all were unsuccessful, whereas pipit young fledged at higher rates from nests initiated in native grassland in June and July than planted grassland nests initiated in May. The number of fledged young from successful nests did not vary strongly with habitat, date or year. This research indicates that planted grasslands attract pipits at the beginning of the breeding season, but habitat suitability and reproductive success substantially declines as the breeding season progresses compared to that found in native grassland.

Oil and natural gas development influence nest‐site selection and nest survival of upland‐nesting waterfowl and shorebirds

ABSTRACTNative grasslands provide important breeding habitat for many upland‐nesting waterfowl and shorebirds. However, recent increases in oil and gas development in native grassland may alter the quantity and quality of this globally threatened habitat. Oil and natural gas development involves construction of roads, trails, and wells; often facilitating invasion by exotic vegetation. Our objectives were to determine 1) whether nest placement by upland‐nesting waterfowl and shorebirds varied with proximity to oil and gas infrastructure; and 2) the extent to which nest survival was influenced by proximity to wells, roads, and trails, as well as percent cover of the exotic crested wheatgrass in southeastern Alberta, Canada, 2010–2011. Mallard (Anas platyrhynchos) and blue‐winged teal (Spatula discors) nests were located within 100 m of wells more than expected by chance, and northern shoveler (Spatula clypeata) and northern pintail (Anas acuta) tended to nest more frequently within 200 m of wells. In contrast, more shorebird nests were located farther from wells than expected. Mallards and blue‐winged teal were also more likely to place their nests near roads. Shorebirds tended to place their nests either close to roads or far from these structures more often than expected by chance. The proportion of mallard nests located in close proximity to trails was greater than expected, but fewer blue‐winged teal nests were located near trails than expected by chance. The top‐ranked models explaining variation in daily nest survival rates of northern shoveler, mallard, and shorebirds included distance to infrastructure variables, although these relationships were weak. Northern shovelers appear to benefit from placing nests closer to trails; daily nest survival rate increased with proximity to trails. However, trails may act as an ecological sink for shorebirds; they were more likely to place nests near trails but daily survival rates were lower near trails. © 2018 The Wildlife Society.

Nest-Site Characteristics and Nesting Success of the Chestnut Thrush

Nest-site characteristics may affect the daily survival rate of avian nests. We monitored the nests of Chestnut Thrush Turdus rubrocanus breeding in an agricultural landscape near the Lianhuashan Natural Reserve (central China) during the breeding seasons of 2013 and 2014. We describe the Chestnut Thrush's breeding ecology and used logistic-exposure methods and an information theoretic approach to assess the factors influencing daily survival rates of nests. Results from model averaging indicated that daily survival rates of nests consistently decreased from habitat edge to interior, contradicting the classic edge effect hypothesis describing predation of avian nests. Concealment of nests from below was positively correlated with nest daily survival rates, whereas concealment from the side and from above were not. These results suggest that determining the various effects of vertical and/or horizontal concealment on nest survival rates may help us assess the variation in the ability of local predators to detect nests.

Species-specific nest predation depends on the total passerine nest density in open-nesting passerines

A large part of the variation in bird reproductive success is often explained by nest predation. Many studies report negative relationships between breeding density and reproductive success due to the predation effect. In this study, we tested the hypothesis that the total nest density should affect nest predation stronger than the nest density of a single species. We used a large sample (n = 320) of Booted Warbler Iduna caligata and Whinchat Saxicola rubetra nests obtained during a period of 6 years in abandoned fields. We used model selection to evaluate effects of density, nest age, season and year on daily nest survival rate. We used a single-species (the distance to the nearest conspecific nest and the number of conspecific nests around the focal nest) and total (the distance to the nearest nest of any passerine species and the total number of passerine nests around the focal nest) nest-density variables. Our results suggest that nest density affects nest survival negatively. Both Booted Warbler and Whinchat nests were more likely to be depredated when neighboring nests of any passerine species were closer. Daily nest survival rates were better predicted by the total nest density than single-species nest density. We suggest that generalist predators performing an area-restricted search may play an important role in nest predation in abandoned fields. The total nest density should be estimated when studying density-dependent nest predation as conclusions about nest predation based on single-species nest densities may be incorrect. The potential impact of density-dependent predation on real nests should be considered when designing artificial nest experiments.

Breeding phenology and nest survival of Cinereous (Circus cinereus) and Long-winged (C. buffoni) Harriers in the agricultural landscapes of north-east Patagonia, Argentina

ABSTRACTWe present novel data on breeding ecology and nest survival of the Cinereous (Circus cinereus) and Long-winged (C. buffoni) Harriers in modified grasslands of southern Argentina and we evaluate variations in daily nest survival rates (DSR) in relation to temporal and habitat variables. We studied three mixed nesting colonies embedded in agricultural landscapes along a road. We found that DSR decreased linearly with time of breeding and increased with vegetation height above the nest and the distance to the road. This is the first and most complete reproductive study concerning two species of conservation concern, namely the Cinereous and Long-winged Harriers in Patagonia. Our study provides valuable and novel insights into the population dynamics of these little-known species.

Linking songbird nest predation to seedling density: Sugar maple masting as a resource pulse in a forest food web.

The ecological literature presents considerable evidence for top‐down forcing on the maintenance of species diversity. Yet, in temperate forests, bottom‐up forces often exert a strong influence on ecosystem functioning. Here, we report on the indirect influence of a pulsed resource, sugar maple (Acer saccharum) seed production, on nest survival in a migratory songbird. We hypothesized that seed production in year t would determine daily nest survival rate in year t + 1 through its effects on seed‐eating rodents. We used the density of sugar maple seedlings (with cotyledons) in year t + 1 as a proxy for seed production in year t and predicted that it would be inversely related to songbird nest survival the same year. We estimated the density of sugar maple seedlings, eastern chipmunk (Tamias striatus) activity, and daily nest survival rate in the ovenbird (Seiurus aurocapilla) over four successive years in a northern hardwood forest of New Brunswick, Canada. Seedling density varied by two orders of magnitude between years, whereas an index of chipmunk activity changed by an order of magnitude. Both variables were positively correlated and negatively correlated to daily nest survival rate. A logistic‐exposure model including only seedling density received the greatest level of support (lowest AICc). Previous studies have reported the effect of sugar maple masting on seed‐eating rodent populations, but the strong link we report between seedling density and songbird nest survival is novel. A nocturnal seed‐eating nest predator, deer mouse (Peromyscus maniculatus), was not considered in our models, which may explain why chipmunk was not the best predictor of daily nest survival rate. The trophic linkages we observed are remarkably strong for a temperate forest ecosystem and might become more prevalent in northeastern North America, at least on calcium‐rich soils, with the loss of large‐diameter beech trees as a result of beech bark disease.

Semi‐arid grassland bird responses to patch‐burn grazing and drought

ABSTRACTAs grassland birds of central North America experience steep population declines with changes in land use, management of remaining tracts becomes increasingly important for population viability. The integrated use of fire and grazing may enhance vegetation heterogeneity and diversity in breeding birds, but the subsequent effects on reproduction are unknown. We examined the influence of patch‐burn grazing management in shortgrass steppe in eastern Colorado on habitat use and reproductive success of 3 grassland bird species, horned lark (Eremophila alpestris), lark bunting (Calamospiza melanocorys), and McCown's longspur (Rhynchophanes mccownii), at several spatial scales during 2011 and 2012. Although no simple direct relationship to patch‐burn grazing treatment existed, habitat selection depended on precipitation‐ and management‐induced vegetation conditions and spatial scale. All species selected taller‐than‐expected vegetation at the nest site, whereas at the territory scale, horned larks and McCown's longspurs selected areas with low vegetation height and sparse cover of tall plants (taller than the dominant shortgrasses). Buntings nested primarily in unburned grassland under average rainfall. Larks and longspurs shifted activity from patch burns during average precipitation (2011) to unburned pastures during drought (2012). Daily survival rate (DSR) of nests varied with time in season, species, weather, and vegetation structure. Daily survival rate of McCown's longspur nests did not vary with foliar cover of relatively tall vegetation at the nest under average precipitation but declined with increasing cover during drought. At the 200‐m scale, increasing cover of shortgrasses, rather than taller plant species, improved DSR of larks and longspurs. These birds experience tradeoffs in the selection of habitat at different spatial scales: tall structure at nests may reduce visual detection by predators and provide protection from sun, wind, and rain, yet taller structure surrounding territories may host nest predators. Patch‐burn grazing management in combination with other strategies that retain taller‐structured vegetation may help sustain a diversity of breeding habitats for shortgrass birds under varying weather conditions. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Non-native predator control increases the nesting success of birds: American mink preying on wader nests

The ongoing decline of breeding wader populations in Europe has been mostly explained by habitat changes and the increasing impact of native predators, but the influence of non-native invasive predators has been neglected. A seven year study of the nesting success of the northern lapwing, common redshank and black-tailed godwit was carried out in Biebrza National Park in north-eastern Poland, alongside the American mink control programme, which was undertaken with low and high intensities of mink control. Indices of mink density, based on the percentage of floating rafts with mink tracks and the number of mink trapped per 100 trap-nights, declined with the increasing number of mink removed in consecutive years. In our model, the mink control and water level covariates explained most of the variation in daily nest survival rates. A decline in mink density led to increases in daily survival rates of nests and to the overall nesting success of all three wader species. Lower water levels led to a decrease in the overall daily survival rate (DSR) but this covariate affected DSR differently throughout the breeding season. These results demonstrate that predation by an introduced species, alongside low water levels during the nesting period, can limit the nesting success of multiple wader species, and that American mink should be considered as a key predator affecting ground-nesting wetland bird populations. Conservation plans for many wader species declining in numbers should include local reductions in mink populations in order to increase nesting success. Thus, intensive continuous mink control is recommended for important nesting refuges, utilising adaptive management to ensure control efforts remain sufficiently high.

Daily Survival Rate and Habitat Characteristics of Nests of Wilson's Plover

Abstract We assessed habitat characteristics and measured daily survival rate of 72 nests of Charadrius wilsonia (Wilson's Plover) during 2012 and 2013 on South Island and Sand Island on the central coast of South Carolina. At both study areas, nest sites were located at slightly higher elevations (i.e., small platforms of sand) relative to randomly selected nearby unused sites, and nests at each study area also appeared to be situated to enhance crypsis and/or vigilance. Daily survival rate (DSR) of nests ranged from 0.969 to 0.988 among study sites and years, and the probability of nest survival ranged from 0.405 to 0.764. Flooding and predation were the most common causes of nest failure at both sites. At South Island, DSR was most strongly related to maximum tide height, which suggests that flooding and overwash may be common causes of nest loss for Wilson's Plovers at these study sites. The difference in model results between the 2 nearby study sites may be partially due to more-frequent flooding at ...

Ring-necked Pheasant Use of Post − Conservation Reserve Program Lands

The Conservation Reserve Program (CRP) has provided millions of ha of cover for numerous wildlife species. Many CRP contracts have expired or will expire, resulting in the loss of critical wildlife cover. The purpose of the current study was to evaluate the potential response of ring-necked pheasant (Phasianus colchicus) to future changes in land use. We selected four land uses that may potentially occur on CRP lands being converted back to agriculture: 1) season-long grazing, 2) hay land, 3) no-till corn (Zea mays), and 4) no-till barley (Hordeum spp.). As a control, 32 ha of CRP grasslands were left idle to mimic land in CRP. Using data from 193 ring-necked pheasant nests, we found nest density was different among land uses (P < 0.01). The control and season-long grazing treatment did not differ from one another (P = 0.42; 0.43 and 0.24 nests∙ha−1, respectively), but both had greater nest densities than no-till corn and no-till barley treatments (P < 0.01; 0.04 and 0.03 nests∙ha−1, respectively). The nest density in the hay treatment (0.16 ± 0.04 nests∙ha−1) and control were different (P = 0.02). Ring-necked pheasant nest site selection was influenced by visual obstruction and vegetation height as hens chose nest sites with taller vertical structure and vegetation heights. Daily survival rates of nests were not influenced by treatment but did increase with greater visual obstruction, increased as a nest aged and throughout the nesting season, and were negatively affected by precipitation events. Our results suggest that maintaining CRP-type grasslands will be beneficial for ring-necked pheasants because of the nesting cover they provide. However, the conversion of CRP to livestock production may be a viable option that provides nesting opportunities for ring-necked pheasant, given vertical structure is available for nesting hens.

Survival chances of ground nests in three different habitats in Krka National Park (Croatia)

Background and Purpose: Diverse Mediterranean wetlands sustain a high diversity of breeding birds. Breeding success of birds nesting on protected wetlands along river Krka is also influenced by predators. The aim of our study was to explore effects of predator pressures on ground nests of strictly protected birds using artificial nest located along environmental gradient. Materials and Methods: In May 2004 in locality Čulišićke bare, by placing out three batches of 25 artificially constructed ground nests in three different habitats: reed bed, marsh and meadow. The nests contained three chicken (real) eggs for the evaluation of nest predation rates, and plasticine (artificial) eggs for predator identification from tooth and bill imprints. Results and Conclusions: The number of nests depredated during one week was highest in wetland habitats: 52% was depredated in the marsh and 32% in the reed bed. However, a much lower damage rate (16%) was experienced in the meadow. The daily survival rate of nests did not differ significantly between the reed bed (0.95) and the marsh (0.91). However, the daily survival rates of nests in the meadow (0.98) was significantly higher (z = 2.49 P = 0.01) than in the marsh, bat no difference was found with comparing with the reed bed. Predators were difficult to determine because plasticine eggs usually disappeared from the nests in the reed bed. In the marsh and the meadow, primary predators were smaller birds, whereas small mammals were also important in the marsh. Nests in which predators succeeded in breaking at least one egg were later destroyed most by Hooded Crows (Corvus cornix). To apply these results for bird protection, the breeding success of certain threatened bird species should be monitored for a longer period.

Depredation Patterns and Northern Bobwhite Nest Success in Field Borders

Northern bobwhite (Colinus virginianus) populations have declined because of habitat loss and fragmentation. Field borders provide additional habitat for northern bobwhites and other wildlife that depend on early-succession habitat. However, their proximity to woods as well as other edge types may result in increased bobwhite nest depredation. We examined if northern bobwhite nest survival in field borders decreased with increasing proximity to edges such as woods, crop fields, ditches, and roads; effects of year, camera presence, and field border width also were considered. We examined if snakes are the primary nest predator with 24-hr video camera surveillance. We searched for and monitored northern bobwhite nests on ~ 77 ha of field borders in southeast North Carolina during summers 2010 and 2011. We found 26 nests and monitored them every 3–4 days. Fourteen nests were monitored with cameras. We built nest survival models using the covariates of distance to nearest woody edge, crop field, ditch, and road as well as year, camera effect, and field border width. The most explanatory model was constant northern bobwhite nest survival with an estimated daily nest survival 6 SE of 0.9512 6 0.0119 (AICc weight 1⁄4 0.23). Models with covariates suggested similar daily nest survival rates. Four snake and two mammalian predation events were recorded on camera. Distance to edge types and field border width did not appear to influence the outcome of nests in an agriculture-dominated landscape. Thus, landowners and managers in an agriculture-dominated landscape may have flexibility with field border placement and distance to edge type as they relate to nest success.

Can island specialists succeed as urban pioneers? Pied imperial-pigeons provide a case study

Context Long-term viability of wildlife populations may be influenced by the adaptive or maladaptive nature of behavioural shifts. Yet, in the short term, implications of novel behaviour are often uncertain, as they were for a newly formed urban nesting colony of pied imperial-pigeons (PIPs) on the mainland coast of north-eastern Australia. It represented unprecedented behaviour, as most of PIPs, also known as Torresian imperial-pigeons, Ducula bicolor/spilorrhoa, breed colonially on remote small islands. Aims The present study would (1) determine whether aggregated mainland nesting continued, (2) evaluate reproductive success, (3) evaluate spatial distribution of nests and (4) explore possible association of reproductive success with predator presence and broad indicators of food availability. Methods With assistance from volunteers, we found mainland PIP nests and revisited them intermittently to monitor progress. We calculated quantitative estimates of nest survival by the Mayfield method and evaluated reproductive output in relation to environmental data from independent sources. Key results During the 2012, 2013 and 2014 breeding seasons, we recorded 436, 387 and 417 PIP nest events at the new mainland colony. Daily nest-survival rates declined progressively and estimated fledgling output decreased over successive seasons from 0.66 to 0.44 per nest event. The highest mainland output was below that estimated for an island PIP colony (0.78) on the basis of sparse prior data. Across potential foraging grounds, there was no negative change in land use and no widespread adverse weather to account for diminishing success. We identified important causes of nest failure among mainland nesting PIPs to be predation, predominantly by birds, and anthropogenic hazards, including tree pruning and collisions with vehicles and windows of buildings. Conclusions With ongoing exposure to these hazards, mainland nesting PIPs cannot be expected to increase productivity; hence, the new colony may be a short-term phenomenon. We infer that the historic success of PIP populations in Queensland stems from their selection of breeding sites on remote islands that are largely free of relevant predators and anthropogenic activity. Implications Future conservation of extant PIP abundance will depend crucially on protection of island breeding sites, because multiple hazards of mainland nesting make it an unfavourable alternative strategy.

A tropical bird with a short breeding season and high rates of nesting success: the breeding ecology of the Star-throated Antwren (Rhopias gularis: Thamnophilidae) in subtropical Brazil

We studied nesting in marked pairs of Star-throated Antwrens (Rhopias gularis) over 3 years to examine whether breeding traits in subtropical Brazil are more similar to temperate patterns of breeding than is typical of the patterns observed within the mostly tropical Thamnophilidae. This Antwren is socially monogamous and permanently territorial, as are all Thamnophilidae, and has a long incubation period (18 days) and shorter nestling period (13 days). Its breeding season is relatively short (<4 months) and nesting success high (36%) compared with those traits of tropical antbirds. Daily nest- survival rate (DSR) during incubation was fairly low and declined throughout the breeding season, whereas DSR was greater and constant during the nestling period. Thus, early nests were more successful and, after hatching, nestlings had a very high probability of fledging (up to 90%). Only males built nests, which can be reused, apparently reducing reproductive demand on females. Pairs did not re-nest in the same season after a successful nesting attempt. Average fecundity was 1.0 ± 0.3 fledglings female−1 year−1, similar to that of tropical thamnophilids. We argue that the timing of breeding and reproductive effort are adjusted to reduce breeding costs in a subtropical climate, resulting in a unique combination of life-history traits for a bird of tropical origin.

Nest predators, nest-site selection and nest success of the Emei Shan Liocichla (Liocichla omeiensis), a vulnerable babbler endemic to southwestern China

The Emei Shan Liocichla (Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success. We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates (DSR). Nest success was calculated using the Mayfield method. In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091 (95 % CI 0.9346–0.9711) (n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels (n = 5), snakes (n = 3), raptors (n = 1) and wasps (n = 1). We found that: (1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla, (2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and (3) the nest-site-selection variables we measured appeared not to be positively associated with nest success. Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.

Avian Nest Success along a Habitat Gradient in the Cross Timbers Oak Savanna

Abstract Oak savanna, once widespread across central North America, has functionally vanished from most of its range due to land conversion or fire suppression and subsequent afforestation. Savanna-associated bird species have exhibited population declines as a result. One of the few areas containing remnant oak savanna is the vast Cross Timbers ecoregion of the south-central Unites States. Previous research in the Midwest showed some bird species exhibited higher rates of nest success (i.e., lower predation of eggs and nestlings) in restored savannas than in closed-canopy forests. Our objective was to quantify patterns of avian nest success across a gradient from open-canopy oak savanna to closed-canopy forest in the Cross Timbers ecoregion of southeastern Kansas. Daily nest survival rates for four common bird species—mourning dove (Zenaida macroura), yellow-billed cuckoo (Coccyzus americanus), brown thrasher (Toxostoma rufum), and northern mockingbird (Mimus polyglottos)—were modeled against covariates ...