Program MARK Research Articles

Northern bobwhite breeding season ecology on a reclaimed surface mine

ABSTRACTSurface coal mining and subsequent reclamation of surface mines have converted large forest areas into early successional vegetative communities in the eastern United States. This reclamation can provide a novel opportunity to conserve northern bobwhite (Colinus virginianus). We evaluated the influence of habitat management activities on nest survival, nest‐site selection, and brood resource selection on managed and unmanaged units of a reclaimed surface mine, Peabody Wildlife Management Area (Peabody), in west‐central Kentucky, USA, from 2010 to 2013. We compared resource selection, using discrete‐choice analysis, and nest survival, using the nest survival model in Program MARK, between managed and unmanaged units of Peabody at 2 spatial scales: the composition and configuration of vegetation types (i.e., macrohabitat) and vegetation characteristics at nest sites and brood locations (i.e., microhabitat). On managed sites, we also investigated resource selection relative to a number of different treatments (e.g., herbicide, disking, prescribed fire). We found no evidence that nest‐site selection was influenced by macrohabitat variables, but bobwhite selected nest sites in areas with greater litter depth than was available at random sites. On managed units, bobwhite were more likely to nest where herbicide was applied to reduce sericea lespedeza (Lespedeza cuneata) compared with areas untreated with herbicide. Daily nest survival was not influenced by habitat characteristics or by habitat management but was influenced by nest age and the interaction of nest initiation date and nest age. Daily nest survival was greater for older nests occurring early in the breeding season (0.99, SE < 0.01) but was lower for older nests occurring later in the season (0.08, SE = 0.13). Brood resource selection was not influenced by macrohabitat or microhabitat variables we measured, but broods on managed units selected areas treated with herbicide to control sericea lespedeza and were located closer to firebreaks and disked native‐warm season grass stands than would be expected at random. Our results suggest the vegetation at Peabody was sufficient without manipulation to support nesting and brood‐rearing northern bobwhite at a low level, but habitat management practices improved vegetation for nesting and brood‐rearing resource selection. Reproductive rates (e.g., nest survival and re‐nesting rates) at Peabody were lower than reported in other studies, which may be related to nutritional deficiencies caused by the abundance of sericea lespedeza. On reclaimed mine lands dominated by sericea lespedeza, we suggest continuing practices such as disking and herbicide application that are targeted at reducing sericea lespedeza to improve the vegetation for nesting and brood‐rearing bobwhite. © 2016 The Wildlife Society.

Daily survival rate of nests is lower in fruiting than non-fruiting tree species for a Hawaiian forest bird, the Kaua̒i ̒elepaio (Chasiempis sclateri)

ABSTRACT Nest-site characteristics are important drivers of nest success in birds, and are particularly important to understand in systems where anthropogenic factors may exacerbate their negative effects on population demographics. In Hawaii, it is suggested that forest bird nests in fruiting tree species may have higher rates of nest predation than in non-fruiting tree species, because fruit is an important dietary component of introduced rats. I assessed the differential daily survival rate (DSR) of nests of Kauai Elepaio (Chasiempis sclateri) on Kauai Island, Hawaii, in fruiting versus non-fruiting tree species using generalized linear models in program MARK. Nests were located in six fruiting tree species (n = 19) and one non-fruiting species (n = 25). Nest-tree reproductive strategy was a driver of DSR (β = −1.15 ± 0.55 SE, 95% CI = −2.23–-0.07) and DSR was lower in fruiting tree species compared to the non-fruiting species (0.975 vs. 0.992, respectively). Most nest failures were attributed to ...

Survival and Cause-Specific Mortality of Coyotes on a Large Military Installation

Abstract Canis latrans (Coyote) recently expanded into the southeastern United States, creating ecologically novel interactions with other species. However, relatively few studies have examined vital rates of southeastern Coyotes or estimated vital rates where individuals are protected from hunting and trapping. In 2011, we captured and attached GPS radiocollars to 31 Coyotes at Fort Bragg Military Installation, NC, where Coyote harvest was restricted. We used a 12-month period (February 2011–January 2012) and known-fate modeling in Program MARK to estimate annual survival. Model-selection results indicated the time-varying model (S[t]) was the most parsimonious model, and. annual survival was 0.80 (95% CI = 0.60–0.91). We documented 7 mortalities, including 2 from vehicles, 2 from offsite trapping, and 3 from unknown causes. Estimated Coyote survival rates at Fort Bragg were similar to most other estimates from the southeastern US. Anthropogenic causes of mortality were important even though hunting and ...

Factors affecting survival in Mediterranean populations of the Eurasian eagle owl

The survival rate is a key parameter for population management and the monitoring of populations. Thus, an analysis of survival rate variations and the factors influencing the same is essential for understanding population dynamics. Here, we study the factors determining the survival and the causes of mortality of the Eurasian eagle owl (Bubo bubo) in two Spanish Mediterranean populations (Murcia and Seville) where the species has a high population density and breeding success; yet its survival rates and the factors that affect them are unknown. Between 2003 and 2010, 63 breeding owls were captured and radio-tracked. Three monthly (quarterly) survival rates were estimated using known-fate models in the program MARK. The mean overall annual survival rate was 0.776 (95 % CI: 0.677, 0.875). We observed survival differences between sexes, and between the breeding and non-breeding periods, although no overwhelming support was found for any particular model. We concluded that (i) females have a lower survival rate than males, probably due to their larger home ranges, which increase the risk of mortality; (ii) the survival rates of both sexes were lower during the non-breeding period; and (iii) the causes of mortality differed significantly between the two populations, gunshot being the main cause in Seville and electrocution in Murcia.

Use of mistletoes by the Grey Go‐away‐bird (Corythaixoides concolor, Musophagidae) in a semi‐arid savannah, south‐west Zimbabwe

AbstractMistletoes are preferred nesting sites for many bird species in a range of habitats. However, no studies have examined the use of mistletoes by nesting birds in the semi‐arid savannah. We studied nesting in mistletoe and its role in determining nesting success in the Grey Go‐away‐bird in south‐west Zimbabwe. We modelled the effects of mistletoe, mistletoe abundance, nest microclimate, concealment and nest height on daily survival rates (DSR) using program MARK. A constant survival model was best fitted for the Grey Go‐away‐bird suggesting a constant nest survival rate across the nesting period. Mistletoe nests had lower DSR than nests placed elsewhere in the canopy. Mistletoe abundance and nest height had a positive association with DSR whereas visibility distance, microclimate and concealment were negatively associated with DSR. Overall, survival for nests in mistletoe was 22.1% compared with 90.5% for nests in other substrates over the 50‐day nesting period. In conclusion, the low nest survival in mistletoe suggests either that the factors used to select mistletoe as nest sites by these birds are poor predictors of nest success or that nesting in mistletoe may be maladaptive.

Predicting the Stability of Endangered Stonecats in the LaPlatte River, Vermont

AbstractStonecats Noturus flavus in Vermont conform to a rare distribution pattern (as designated by Rabinowitz 1981) because their known distribution within the state is limited to the LaPlatte and Missisquoi rivers. We focused on Stonecats in the LaPlatte River to predict the stability of the population. During 2012–2014, we captured Stonecats via backpack electrofishing; fish were PIT‐tagged (>90 mm TL) and marked with visible implant elastomer. Among the 1,671 Stonecats that were captured, 1,252 were PIT‐tagged. Only 156 (12%) of the PIT‐tagged fish were recaptured, and only 22 of those individuals were recaptured more than once. The Pradel model in Program MARK was used to estimate apparent survival (Φ) and seniority, which were used to derive the rate of population change (λ) for the Stonecat encounter histories we studied. We examined a total of 64 models in our candidate set, with the following covariates: TL at first capture, maximum temperature, season, maximum discharge, and area sampled. Survival estimates were highest in the spring (range of daily Φ = 0.9993–0.9995) and increased with greater TL at first capture. We also estimated increases in capture probability with increasing area sampled. We derived an annual λ of 0.9794, which indicates a slightly decreasing population. However, our λ estimate contained uncertainty that was likely increased due to the low recapture rates. Additional years of data could increase the accuracy of the λ estimate. In the meantime, we have provided insight into Stonecat population parameters that were otherwise unknown.Received December 22, 2015; accepted March 1, 2016 Published online June 29, 2016

Grasslands bird occupancy of native warm‐season grass

ABSTRACTGrassland birds have declined more than any other guild in the United States because of loss and degradation of native grasslands. The United States Department of Agriculture Farm Bill programs have restored some native warm‐season grasses (NWSG), but populations of many grassland bird species continue to decline. Market‐based NWSG uses focused on hay, pasture, and biofuel feedstock may be more appealing to landowners, and may still provide grassland bird habitat on the landscape. We examined breeding grassland bird occupancy of 102 NWSG production fields including 5 treatments (control [n = 37], grazing [n = 7], hay [n = 22], seed [n = 21], and biofuel [n = 15] production) in Kentucky and Tennessee during 2009–2010 breeding seasons. We used a robust design model in Program MARK to determine occupancy and detection rates for grassland birds. We modeled occupancy differences among treatments and sites (i.e., KY, TN), and included covariates (i.e., field‐level vegetation metrics and landscape composition at 3 scales [250 m, 500 m, and 1 km]) for eastern meadowlark (Sturnella magna), field sparrow (Spizella pusilla), grasshopper sparrow (Ammodramus savannarum), northern bobwhite (Colinus virginianus), and red‐winged blackbird (Agelaius phoeniceus). Covariates that influenced occupancy included treatment (field sparrow, 2009 only), site (eastern meadowlark, grasshopper sparrow, and northern bobwhite), percent NWSG cover (positive, red‐winged blackbird), and percent forest cover within 250 m (negative for eastern meadowlark, grasshopper sparrow, northern bobwhite, and red‐winged blackbird) or within 1 km (negative, field sparrow). Our results suggest that forest cover in the surrounding landscape negatively influences species occupancy, and species occupancy generally did not differ among NWSG production treatments. These treatments could be an alternative means to provide grassland bird habitat within an agriculture production landscape. © 2016 The Wildlife Society.

Survival of desert mule deer fawns in central Arizona

Abstract Desert mule deer (Odocoileus hemionus eremicus) densities in central Arizona are below historic levels, likely due to neonatal mortality influencing desert mule deer population dynamics. However, no direct assessments have been made into causes and timing of neonatal mortalities in central Arizona. The objectives of our study were to determine the causes and timing of mortalities of desert mule deer fawns, estimate the annual survival rate of adult females and fawns, and quantify predator effects on fawn survival. In 2007 and 2008 we captured 52 adult female desert mule deer and equipped pregnant females with vaginal implant transmitters to aid in capturing fawns. We performed survival analyses using Program MARK and compared competing models with Akaike's information criterion. We captured 44 desert mule deer fawns; summer survival was 0.432 (95% CI = 0.292–0.584) and annual fawn survival was 0.071 (95% CI = 0.013–0.303). Predation accounted for 64% of fawn mortality. Probability of fawn surviva...

Louisiana Waterthrush and Benthic Macroinvertebrate Response to Shale Gas Development

Abstract Because shale gas development is occurring over large landscapes and consequently is affecting many headwater streams, an understanding of its effects on headwater-stream faunal communities is needed. We examined effects of shale gas development (well pads and associated infrastructure) on Louisiana waterthrush Parkesia motacilla and benthic macroinvertebrate communities in 12 West Virginia headwater streams in 2011. Streams were classed as impacted (n = 6) or unimpacted (n = 6) by shale gas development. We quantified waterthrush demography (nest success, clutch size, number of fledglings, territory density), a waterthrush Habitat Suitability Index, a Rapid Bioassessment Protocol habitat index, and benthic macroinvertebrate metrics including a genus-level stream-quality index for each stream. We compared each benthic metric between impacted and unimpacted streams with a Student's t-test that incorporated adjustments for normalizing data. Impacted streams had lower genus-level stream-quality index scores; lower overall and Ephemeroptera, Plecoptera, and Trichoptera richness; fewer intolerant taxa, more tolerant taxa, and greater density of 0–3-mm individuals (P ≤ 0.10). We then used Pearson correlation to relate waterthrush metrics to benthic metrics across the 12 streams. Territory density (no. of territories/km of stream) was greater on streams with higher genus-level stream-quality index scores; greater density of all taxa and Ephemeroptera, Plecoptera, and Trichoptera taxa; and greater biomass. Clutch size was greater on streams with higher genus-level stream-quality index scores. Nest survival analyses (n = 43 nests) completed with Program MARK suggested minimal influence of benthic metrics compared with nest stage and Habitat Suitability Index score. Although our study spanned only one season, our results suggest that shale gas development affected waterthrush and benthic communities in the headwater streams we studied. Thus, these ecological effects of shale gas development warrant closer examination.

Survival of reintroduced Asian houbara in United Arab Emirates’ reserves

ABSTRACTIncreasing knowledge of post‐release survival and habitat requirements of translocated animals is critical to improve success of conservation programs. We estimated survival of reintroduced captive‐bred Asian houbara bustards (Chlamydotis macqueenii) in reserves of western United Arab Emirates where plantations exist as supplementary feeding sites. We explored factors influencing short‐ (3 months after release) and long‐term (tri‐monthly periods after third month of release) survival rates of released birds. We modeled life histories of individually tracked houbara using Program MARK. Mean short‐term survival probability (0.76 ± 0.14 SD) was lower than mean long‐term survival (0.86 ± 0.03 SD), and observed group size and the age of released birds positively correlated with short‐term survival. We hypothesize that higher quality habitat (plantations) affected survival; larger groups occurred in plantations and older birds might be better able to maintain access to plantations. Long‐term survival was negatively influenced by subsequent release events. Releasing more individuals increases local houbara density. This may lead to food depletion, increase in density‐dependent mechanisms between individuals, or both. Short‐ and long‐term survival rates suggest that food availability at the release sites, together with intraspecific interactions, may influence survival of newly released and established individuals. To improve the management of translocated animals, the impact of managed food resources should be quantified to assess how it might affect population vital rates. © 2016 The Wildlife Society.

Age-specific survival of reintroduced swift fox in Badlands National Park and surrounding lands

In 2003, a reintroduction program was initiated at Badlands National Park (BNP), South Dakota, USA, with swift foxes (Vulpes velox) translocated from Colorado and Wyoming, USA, as part of a restoration effort to recover declining swift fox populations throughout its historical range. Estimates of age-specific survival are necessary to evaluate the potential for population growth of reintroduced populations. We used 7 years (2003–2009) of capture–recapture data of 243 pups, 29 yearlings, and 69 adult swift foxes at BNP and the surrounding area to construct Cormack–Jolly–Seber model estimates of apparent survival within a capture–mark–recapture framework using Program MARK. The best model for estimating recapture probabilities included no differences among age classes, greater recapture probabilities during early years of the monitoring effort than later years, and variation among spring, winter, and summer. Our top ranked survival model indicated pup survival differed from that of yearlings and adults and varied by month and year. The apparent annual survival probability of pups (0.47, SE = 0.10) in our study area was greater than the apparent annual survival probability of yearlings and adults (0.27, SE = 0.08). Our results indicate low survival probabilities for a reintroduced population of swift foxes in the BNP and surrounding areas. Management of reintroduced populations and future reintroductions of swift foxes should consider the effects of relative low annual survival on population demography. © 2016 The Wildlife Society.

Long-term lesser prairie-chicken nest ecology in response to grassland management

Long-term population and range declines from habitat loss and fragmentation caused the lesser prairie-chicken (Tympanuchus pallidicinctus) to be a species of concern throughout its range. Current lesser prairie-chicken range in New Mexico and Texas is partially restricted to sand shinnery oak (Quercus havardii; hereafter shinnery oak) prairies, on which cattle grazing is the main socioeconomic driver for private landowners. Cattle producers within shinnery oak prairies often focus land management on shrub eradication using the herbicide tebuthiuron to promote grass production for forage; however, herbicide application alone, and in combination with grazing, may affect nest site selection and nest survival of lesser prairie-chickens through the reduction of shinnery oak and native grasses. We used a controlled, paired, completely randomized design study to assess the influence of grazing and tebuthiuron application and their combined use on nest site selection and nest survival from 2001 to 2010 in Roosevelt County, New Mexico, USA at 2 spatial scales (i.e., treatment and microhabitat) in 4 treatments: tebuthiuron with grazing, tebuthiuron without grazing, no tebuthiuron with grazing, and a control of no tebuthiuron and no grazing. Grazing treatment was a short-duration system in which plots were grazed once during the dormant season and once during the growing season. Stocking rate was calculated each season based on measured forage production and applied to remove ≤25% of available herbaceous material per season. At the treatment scale, we compared nest site selection among treatments using 1-way χ2 tests and nest survival among treatments using a priori candidate nest survival models in Program MARK. At the microhabitat scale, we identified important habitat predictors of nest site selection and nest survival using logistic regression and a priori candidate nest survival models in Program MARK, respectively. Females typically used treatments as expected and we did not detect trends in selection. Nest survival did not differ among treatments. At the microhabitat scale, nest sites had less bare ground (P = 0.001) and greater angles of obstruction (P ≤ 0.001) compared to random sites. There was a high degree of model selection uncertainty among our candidate models at the microhabitat scale and survival estimates were similar among habitat covariates. Results suggest a tebuthiuron application rate of 0.60 kg/ha, short-duration grazing, and a combination of these management techniques were not detrimental to lesser prairie-chicken nest site selection or nest survival. However, intensified management that increases bare ground or reduces overhead cover may negatively affect lesser prairie-chicken nesting habitat and nest survival. © 2016 The Wildlife Society.

Population size of endemic Rana tavasensis in its terra typica, Turkey

We applied capture-mark-recapture (CMR) methods to estimate the population size of the Tavas frog Rana tavasensis in its terra typica. For this purpose, we used Pollock?s robust design in program MARK in the 2011-2015 breeding seasons in its terra typica. Based on the selected model, equal catchability of each individual and absence of temporary migration were found to be the most likely biological hypotheses. Population sizes were estimated as 398, 348, 275, and 117 individuals during the four study years, respectively. Annual capture probabilities were estimated to average 0.07, and annual survival rates across years averaged 0.19. The year-specific estimations showed a remarkable decline in population size and survival rates. Anthropogenic factors, such as off-road activities, recreational activities, and animal grazing, might have played a role in this decline. This trend provides us with useful knowledge for conservation and management activities.

Seasonal Effects of Habitat on Sources and Rates of Snowshoe Hare Predation in Alaskan Boreal Forests.

Survival and predation of snowshoe hares (Lepus americanus) has been widely studied, yet there has been little quantification of the changes in vulnerability of hares to specific predators that may result from seasonal changes in vegetation and cover. We investigated survival and causes of mortalities of snowshoe hares during the late increase, peak, and decline of a population in interior Alaska. From June 2008 to May 2012, we radio-tagged 288 adult and older juvenile hares in early successional and black spruce (Picea mariana) forests and, using known-fate methods in program MARK, evaluated 85 survival models that included variables for sex, age, and body condition of hares, as well as trapping site, month, season, year, snowfall, snow depth, and air temperature. We compared the models using Akaike’s information criterion with correction for small sample size. Model results indicated that month, capture site, and body condition were the most important variables in explaining survival rates. Survival was highest in July, and more generally during summer, when alternative prey was available to predators of hares. Low survival rates coincided with molting periods, breeding activity in the spring, and the introduction of juveniles to the sample population in the fall. We identified predation as the cause of mortality in 86% of hare deaths. When the source of predation could be determined, hares were killed more often by goshawks (Accipiter gentilis) than other predators in early successional forest (30%), and more often by lynx (Lynx canadensis) than other predators in black spruce forest (31%). Great horned owls (Bubo virginianus) and coyotes (Canis latrans) represented smaller proportions of hare predation, and non-predatory causes were a minor source (3%) of mortality. Because hares rely on vegetative cover for concealment from predators, we measured cover in predation sites and habitats that the hares occupied and concluded that habitat type had a greater influence on the sources of predation than the amount of cover in any given location within a habitat. Our observations illustrate the vulnerability of hares to predators in even the densest coniferous habitat available in the boreal forest, and indicate strong seasonal changes in the rates and sources of predation.

Demystifying the Sundarban tiger: novel application of conventional population estimation methods in a unique ecosystem

AbstractConserving large populations with unique adaptations is essential for minimizing extinction risks. Sundarban mangroves (>10,000 km2) are the only mangrove inhabited by tigers. Baseline information about this tiger population is lacking due to its man‐eating reputation and logistic difficulties of sampling. Herein, we adapt photographic capture‐mark‐recapture (CMR) and distance sampling to estimate tiger and prey densities. We placed baited camera stations in a typical mangrove in 2010 and 2012. We used telemetry based tiger home‐range radius (5.73 km, SE 0.72 km) to estimate effective trapping area (ETA). An effort of 407 and 1073 trap nights were exerted to photocapture 10 and 22 unique tigers in 2010 and 2012. We accounted for use of bait by modelling behaviour and heterogeneity effects in program MARK and secr package in program R. Using traditional CMR, tiger number was estimated at 11 (SE 2) and density at 4.07 (SE range 3.09–5.17) in 2010 while in 2012, tiger number was 24 (SE 3) and density 4.63 (SE range 3.92–5.40) tigers/100 km2. With likelihood based spatially explicit CMR, tiger densities were estimated at 4.08 (SE 1.51) in 2010 and 5.81 (SE 1.24) tigers/100 km2 in 2012. Using distance sampling along water channels, we estimated chital density at 5.24/km2, SE 1.23 which could potentially support 4.68 tigers/100 km2 [95 % CI (3.92, 5.57)]. Our estimates suggest that Sundarban tiger population is one of the largest in the world and therefore merits high conservation status.

Influence of Habitat and Intrinsic Characteristics on Survival of Neonatal Pronghorn.

Increased understanding of the influence of habitat (e.g., composition, patch size) and intrinsic (e.g., age, birth mass) factors on survival of neonatal pronghorn (Antilocapra americana) is a prerequisite to successful management programs, particularly as they relate to population dynamics and the role of population models in adaptive species management. Nevertheless, few studies have presented empirical data quantifying the influence of habitat variables on survival of neonatal pronghorn. During 2002–2005, we captured and radiocollared 116 neonates across two sites in western South Dakota. We documented 31 deaths during our study, of which coyote (Canis latrans) predation (n = 15) was the leading cause of mortality. We used known fate analysis in Program MARK to investigate the influence of intrinsic and habitat variables on neonatal survival. We generated a priori models that we grouped into habitat and intrinsic effects. The highest-ranking model indicated that neonate mortality was best explained by site, percent grassland, and open water habitat; 90-day survival (0.80; 90% CI = 0.71–0.88) declined 23% when grassland and water increased from 80.1 to 92.3% and 0.36 to 0.40%, respectively, across 50% natal home ranges. Further, our results indicated that grassland patch size and shrub density were important predictors of neonate survival; neonate survival declined 17% when shrub density declined from 5.0 to 2.5 patches per 100 ha. Excluding the site covariates, intrinsic factors (i.e., sex, age, birth mass, year, parturition date) were not important predictors of survival of neonatal pronghorns. Further, neonatal survival may depend on available land cover and interspersion of habitats. We have demonstrated that maintaining minimum and maximum thresholds for habitat factors (e.g., percentages of grassland and open water patches, density of shrub patches) throughout natal home ranges will in turn, ensure relatively high (>0.50) neonatal survival rates, especially as they relate to coyote predation. Thus, landscape level variables (particularly percentages of open water, grassland habitats, and shrub density) should be incorporated into the development or implementation of pronghorn management plans across sagebrush steppe communities of the western Dakotas, and potentially elsewhere within the geographic range of pronghorn.

The Effect of Novel Research Activities on Long-term Survival of Temporarily Captive Steller Sea Lions (Eumetopias jubatus).

Two novel research approaches were developed to facilitate controlled access to, and long-term monitoring of, juvenile Steller sea lions for periods longer than typically afforded by traditional fieldwork. The Transient Juvenile Steller sea lion Project at the Alaska SeaLife Center facilitated nutritional, physiological, and behavioral studies on the platform of temporary captivity. Temporarily captive sea lions (TJs, n = 35) were studied, and were intraperitoneally implanted with Life History Transmitters (LHX tags) to determine causes of mortality post-release. Our goal was to evaluate the potential for long-term impacts of temporary captivity and telemetry implants on the survival of study individuals. A simple open-population Cormack-Jolly-Seber mark-recapture model was built in program MARK, incorporating resightings of uniquely branded study individuals gathered by several contributing institutions. A priori models were developed to weigh the evidence of effects of experimental treatment on survival with covariates of sex, age, capture age, cohort, and age class. We compared survival of experimental treatment to a control group of n = 27 free-ranging animals (FRs) that were sampled during capture events and immediately released. Sex has previously been show to differentially affect juvenile survival in Steller sea lions. Therefore, sex was included in all models to account for unbalanced sex ratios within the experimental group. Considerable support was identified for the effects of sex, accounting for over 71% of total weight for all a priori models with delta AICc <5, and over 91% of model weight after removal of pretending variables. Overall, most support was found for the most parsimonious model based on sex and excluding experimental treatment. Models including experimental treatment were not supported after post-hoc considerations of model selection criteria. However, given the limited sample size, alternate models including effects of experimental treatments remain possible and effects may yet become apparent in larger sample sizes.

Nesting success of native and introduced forest birds on the island of Kaua‘i

Forests of the Hawaiian archipelago are a global hotspot for conserving avian diversity and contain among the world's most imperiled species. Demographic studies are necessary to determine primary causes of Hawaiian forest bird population declines. We conducted research on the nesting success of multiple bird families on the island of Kaua‘i, allowing us to investigate the importance of factors related to breeding biology on forest bird declines at a community scale. Our study included two Hawaiian honeycreepers, ‘anianiau Magumma parva and ‘apapane Himatione sanguinea, a native monarch flycatcher, Kaua‘i ‘elepaio Chasiempis sclateri, and one introduced species, Japanese white‐eye Zosterops japonicus. Data from 123 nests showed that nesting success ± SE, estimated using program MARK, was low for ‘apapane (0.23 ± 0.10), but did not vary substantially among our other study species (‘anianiau = 0.56 ± 0.09, Kaua‘i ‘elepaio = 0.63 ± 0.08, Japanese white‐eye = 0.52 ± 0.11). Causes of nest loss for 51 nest failures included nest predation (43%), unknown (25%), empty after termination with no signs of nest predation (e.g. eggshell or chick remains in nest, disheveled nest) (24%), and abandoned clutch or brood (4% each). Kaua‘i ‘elepaio suffered more than twice as many nest losses to predation compared to our other study species, but also had the highest nesting success; and, ‘apapane suffered least to nest predation, but had the lowest nesting success. Further, rates of nesting success derived in our study were relatively high compared to multi‐species studies in mainland tropics. Therefore, although nest predation accounted for the greatest proportion of nest failures, it may not be a cause of forest bird population declines in our system. We suggest that future demographic studies focus on post‐fledgling, juvenile, and adult survival, in addition to the importance of double‐brooding and renesting attempts on annual reproductive success.

Updated assessment of hatchery‐reared pallid sturgeon (Forbes &amp; Richardson, 1905) survival in the lower Missouri River

As pallid sturgeon, Scaphirhynchus albus (Forbes & Richardson, 1905), natural reproduction and recruitment remains very minimal in the lower Missouri River from Gavins Point Dam (river kilometer [rkm] 1305.2) to the confluence with the Mississippi River (rkm 0.0), hatchery supplementation and river-wide monitoring efforts have continued. Annual survival estimates of hatchery-reared pallid sturgeon stocked in the lower Missouri River were previously estimated during 1994–2008. Low recapture rates prior to 2006 limited the data available to estimate survival, which resulted in considerable uncertainty for the estimate of annual survival of age-1 fish. Therefore, the objective was to provide more precise estimates of annual survival of pallid sturgeon using five additional years of stocking and sampling. The Cormack-Jolly-Seber model structure provided in program MARK was used to estimate the age-specific survival estimates. Over 135 000 hatchery-reared pallid sturgeon were released during 1994–2011 and recaptured at a rate of 1.9%, whereby estimates for the annual survival of age-0 (Ø = 0.048) and >age-1 (Ø = 0.931) were similar to those previously reported, but the age-1 (Ø = 0.403) survival estimate was 52% lower. Post hoc analysis using time-specific survival estimates indicated lower survival for age-1 fish post-2003 year classes, relative to the pre-2002 year classes. An analysis confirms that hatchery-reared pallid sturgeon continue to survive in the wild. However, low survival during the first 2 years of life is a management concern as efforts are aimed at maximizing genetic diversity and population growth. A follow-up analysis also demonstrated the variability of capture rates and survival over time, which reinforces the need to continue to monitor and evaluate mark-recapture data. The mark-recapture efforts have provided demographic parameter estimates that remain a critical component for species recovery as these data are incorporated into population models.

Survival of Female Bighorn Sheep (Ovis canadensis) in the Black Hills, South Dakota

Abstract Bighorn sheep (Ovis canadensis) were re- introduced into the Black Hills, South Dakota, U.S.A. in 1965. To date limited information exists concerning vital rates of this population. From 2010 to 2013, we estimated survival and cause-specific mortality of 55 adult female bighorn sheep in three herds in the east-central Black Hills. We documented 21 mortalities. Of those, pneumonia (19%) and predation (19%) accounted for most known causes of mortality; however, we were unable to ascertain cause of death for 47.6% of mortalities. We used a known fate analysis in Program MARK to estimate monthly survival; our best approximating model indicated survival differed during May–Jun compared with the remainder of the year. Monthly survival estimates for May–Jun were 0.95 (95% CI = 0.91–0.97) compared with 0.99 (95% CI = 0.98–0.99) for Jul–Apr, and overall annual survival was 0.81 (95% CI = 0.72–0.87). We found little support for the hypothesis that survival was influenced by body mass or nutritional c...