Taxonomic voucher specimens for study of post-wildfire forest habitat in Douglas County, Oregon

this publication provides data about voucher specimens deposited in the museum in conjunction with a research project on pollinators

Brown-headed cowbird nestlings influence nestmate begging, but not parental feeding, in hosts of three distinct sizes

Keywords: begging brood parasitism brown-headed cowbird host-parasite interaction Molothrus ater offspring solicitation parent feeding provisioning behaviour Avian brood parasites typically depress the fitness of their hosts by reducing the number of host offspring produced, yet little is known about how parasitic nestlings influence the behaviour of host parents and host offspring. In this study, we used three hosts of the brown-headed cowbird, Molothrus ater, that varied in size (i.e. smaller, similar to and larger than cowbirds of a given age) to determine whether parasitic nestlings altered patterns of food provisioning by host parents and begging by host young under field conditions. Adult provisioning did not change in the presence of a cowbird but instead was influenced by feeding treatment and host size. In parasitized broods where nestlings differed in size (i.e. the small and large hosts), the larger nestling received the majority of food brought to the nest, regardless of whether it was the cowbird or host nestling. In contrast, similar-sized host nestlings received a similar amount of food in parasitized and unparasitized host broods. Relative to unparasitized broods, the presence of a cowbird led to increased begging intensity by the small host, had no clear effect on begging behaviour of the intermediate-sized host, and reduced begging intensity of the large host. Taken together, these results suggest the presence of a cowbird did not lead to changes in provisioning behaviour in parents, and the extent to which cowbirds influenced host begging behaviour depended on the size of the host.

Taxonomic voucher specimens for study of bee communities in intensively managed Douglas-fir forests in the Oregon Coast Range

Understanding how pollinators respond to anthropogenic land use is key to conservation of biodiversity and ecosystem services, but few studies have addressed this topic in coniferous forests, particularly those managed intensively for wood production. This study reports on voucher material generated as part of Zitomer et al. (2023), that assessed changes in wild bee communities with time since harvest in 60 intensively managed Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range across a gradient in stand age spanning a typical harvest rotation (0-37 years post-harvest). We additionally assessed relationships of bee diversity and community composition to relevant habitat features, including availability of floral resources and nest sites, understory vegetation characteristics, and composition of the surrounding landscape. Specimens were collected using a combination of passive sampling methods-blue vane traps and white, blue, and yellow bowl traps- and hand-netting and were identified to the lowest possible taxonomic level by A.R. Moldenke and L.R. Best. Four hundred and ten taxonomic voucher specimens were deposited into the Oregon State Arthropod Collection (Accession# OSAC_AC_2023_01_09-001-01) to serve as a reference for future research

Use of created snags by cavity-nesting birds across 25 years

Snags are important habitat features for many forest-dwelling species, so reductions in the number of snags can lead to the loss of biodiversity in forest ecosystems. Intentional snag creation is often used in managed forests to mitigate the long-term declines of naturally created snags, yet information regarding the use of snags by wildlife across long timescales (>20 yr) is lacking and prevents a complete understanding of how the value of created snags change through time. We used a long-term experiment to assess how harvest treatment (i.e., small-patch group selection, 2-story, and clearcut) and snag configuration (i.e., scattered and clustered) influenced nesting in and foraging on 25-27-year-old Douglas-fir (Pseudotsuga menziesii) snags by cavity-nesting birds. In addition, we compared our contemporary measures of bird use to estimates obtained from historical surveys conducted on the same group of snags to quantify how bird use changed over time. Despite observing created snags for >750hours across 2 consecutive breeding seasons, we found limited evidence of nesting activity. Only 11% of created snags were used for breeding, with nesting attempts by 4 bird species (n=36 nests); however, we detected 12 cavity-nesting species present on our study sites. Furthermore, nearly all nests (94%) belonged to the chestnut-backed chickadee (Poecile rufescens), a weak cavity-excavating species that requires well-decayed wood for creating nest cavities. Our surveys also recorded few observations of birds using created snags as foraging substrates, with only 1 foraging event recorded for every 20hours of observation. We detected 82% fewer nests and recorded 7% fewer foraging observations during contemporary field work despite spending >7.5 times more effort observing created snags relative to historical surveys. We conclude that 25-27-year-old created Douglas-fir snags provided limited opportunities for nesting and foraging by most cavity-nesting birds, and that the period of greatest use by this group occurred within 5-15 years of creation. (c) 2018 The Wildlife Society. We used a long-term experiment to assess how harvest type and snag configuration influenced nesting in and foraging on 25-27-year-old Douglas-fir snags by cavity-nesting birds. Despite observing these snags for >750 hours across 2 consecutive breeding seasons, we conclude that they provided limited opportunities for nesting and foraging by most cavity-nesting birds

Winding Number Correlation Functions and Cosmic String Formation

We develop winding number correlation functions that allow us to assess the role of field fluctuations on vortex formation in an Abelian gauge theory. We compute the behavior of these correlation functions in simple circumstances and show how fluctuations are important in the vicinity of the phase transition. We further show that, in our approximation, the emerging population of long/infinite string is produced by the classical dynamics of the fields alone, being essentially unaffected by field fluctuations.Comment: Latex file, 27 pages. 8 figures, available in compressed form by anonymous ftp from ftp://euclid.tp.ph.ic.ac.uk/papers/94-5_39.fig Latex and postscript versions also available at http://euclid.tp.ph.ic.ac.uk/Papers/index.htm

N-Terminal Pro–B-Type Natriuretic Peptide in the Emergency Department: The ICON-RELOADED Study

Background Contemporary reconsideration of diagnostic N-terminal pro–B-type natriuretic peptide (NT-proBNP) cutoffs for diagnosis of heart failure (HF) is needed. Objectives This study sought to evaluate the diagnostic performance of NT-proBNP for acute HF in patients with dyspnea in the emergency department (ED) setting. Methods Dyspneic patients presenting to 19 EDs in North America were enrolled and had blood drawn for subsequent NT-proBNP measurement. Primary endpoints were positive predictive values of age-stratified cutoffs (450, 900, and 1,800 pg/ml) for diagnosis of acute HF and negative predictive value of the rule-out cutoff to exclude acute HF. Secondary endpoints included sensitivity, specificity, and positive (+) and negative (−) likelihood ratios (LRs) for acute HF. Results Of 1,461 subjects, 277 (19%) were adjudicated as having acute HF. The area under the receiver-operating characteristic curve for diagnosis of acute HF was 0.91 (95% confidence interval [CI]: 0.90 to 0.93; p < 0.001). Sensitivity for age stratified cutoffs of 450, 900, and 1,800 pg/ml was 85.7%, 79.3%, and 75.9%, respectively; specificity was 93.9%, 84.0%, and 75.0%, respectively. Positive predictive values were 53.6%, 58.4%, and 62.0%, respectively. Overall LR+ across age-dependent cutoffs was 5.99 (95% CI: 5.05 to 6.93); individual LR+ for age-dependent cutoffs was 14.08, 4.95, and 3.03, respectively. The sensitivity and negative predictive value for the rule-out cutoff of 300 pg/ml were 93.9% and 98.0%, respectively; LR− was 0.09 (95% CI: 0.05 to 0.13). Conclusions In acutely dyspneic patients seen in the ED setting, age-stratified NT-proBNP cutpoints may aid in the diagnosis of acute HF. An NT-proBNP <300 pg/ml strongly excludes the presence of acute HF

Wild bee diversity is enhanced by experimental removal of timber harvest residue within intensively managed conifer forest

The use of timber harvest residue as an energy source is thought to have environmental benefits relative to food-based crops, yet the ecological impact of this practice remains largely unknown. We assessed whether the abundance and diversity of wild bees (Apoidea) were influenced by the removal of harvest residue and associated soil compaction within managed conifer forest in western Oregon, USA. We sampled bees over two years (2014-2015) on study plots that were subjected to five treatments representing gradients in removal of harvest residue and soil compaction. We collected >7,500 bee specimens from 92 distinct species/morphospecies that represented five of the seven bee families. We trapped 3x more individuals in the second year of the study despite identical sampling effort in both years, with most trapped bees classified as ground-nesting species. Members of the sweat bee family (Halictidae) comprised more than half of all specimens, and the most abundant genus was composed of metallic green bees (Agapostemon, 33.6%), followed by long-horned bees (Melissodes, 16.5%), sweat bees (Halictus, 15.9%), and bumble bees (Bombus, 13.6%). In both years, abundance and observed species richness were greatest in the most intensive harvest residue treatment, with other treatments having similar values for both measures. Our study indicates that early successional managed conifer forest that has experienced removal of harvest residue can harbor a surprising diversity of wild bees, which are likely to have important contributions to the broader ecological community through the pollination services they provide

Experimental brood enlargement differentially influences the magnitude of the corticosterone stress response in closely related, co-occurring songbirds

1. Rearing environments can shape offspring phenotype across taxa, yet little is known about how brood size influences hypothalamic-pituitary axis functioning, whether its expression trades off with growth, and the degree to which these -relationships vary between species. 2. We evaluated how brood size influenced nestling physiological (glucocorticoids) and somatic traits (growth), and the extent to which their relationship differed between two closely related, sympatric songbirds when experiencing identical rearing environments. Specifically, we used a cross-fostering approach to alter brood size and create an experimental gradient of nestmate competition, and then tested whether experimentally manipulated brood sizes resulted in nestlings with altered concentrations of corticosterone and whether corticosterone responses traded off with growth. 3. Nestlings of both species experienced elevated concentrations of baseline and stressor-induced corticosterone when raised in enlarged broods, relative to control and reduced broods, but neither measurement was found to trade off with growth or be linked to survival to fledging. 4. In contrast, we found divergence in the magnitude of the corticosterone stress response between species across all brood treatments, with greater stressor-induced corticosterone concentrations found in the Violet-green Swallow (Tachycineta thalassina) relative to the closely related Tree Swallow (T. bicolor). 5. Our study demonstrated that brood size can lead to changes in offspring corticosterone concentrations in swallows and that nestlings of sympatric species, even those that are closely related and ecologically similar, can diverge in their corticosterone stress response when experiencing identical rearing conditions. 6. We conclude that corticosterone appears to play a key role for balancing energetic demands that arise in the face of nestmate competition in Tachycineta swallows and that elevated concentrations of corticosterone may enhance offspring survival during challenging environmental conditions, such as when brood competition is strong

High Levels of Relatedness between Brown-Headed Cowbird (Molothrus ater) Nestmates in a Heavily Parasitized Host Community

Multiple parasitism of host nests by generalist brood parasites reflects the decisions of laying females and may influence the development and behavior of parasitic young. We used microsatellite and mtDNA control-region haplotype data to examine the relatedness of Brown-headed Cowbird (Molothrus ater) offspring in multiply parasitized nests sampled from a heavily parasitized host community in northeastern Kansas. We also examined how host nest availability influenced the degree of multiple parasitism, and used community-wide parasitism data to explore whether female cowbirds were constrained in their laying decisions. Relatedness estimates for all suitable pairwise comparisons (n = 94 from 41 multiply parasitized nests) found that the mean likelihood than an individual cowbird in a multiply parasitized nest shared its nest with a full sibling was 40.4% (95% confidence interval: 28.4–52.4%), indicating that many cowbird offspring were reared with full siblings. Extensive community-wide parasitism data revealed that most cowbird offspring shared the nest with ≥1 other conspecific. Additionally, we found that the proportion of available host nests increased steeply at the start of the breeding season and remained high for most of the breeding season, but that the degree of multiple parasitism was unrelated to the number of new nests. We found evidence that laying decisions of female cowbirds were constrained, which suggests that heavy parasitism levels were due to a high degree of competition for host nests. This intense competition for host nests, in turn, results in cowbird offspring often competing with conspecifics in our population, including full siblings, for host parental care.Keywords: Molothrus ater, Brown-headed Cowbird, nestmate relatedness, kinship, generalist brood parasite, laying patter