Factors influencing colorectal cancer screening decision-making among average-risk US adults.

Colorectal cancer (CRC) screening rates remain suboptimal in the US. We examined patient-focused concerns and influence of various factors (e.g., test attributes, provider recommendation) on CRC screening decision-making. We conducted a web survey with 1595 US adults aged 40-75 from a nationally representative panel in November 2019 (completion rate: 31.3 %). Analyses focused on individuals aged 45-75 years at average-risk for CRC (n = 1062). All participants rated their level of concern about various CRC screening test/procedure attributes. Participants who have screened previously designated the three most important attributes for choosing a screening method and rated how various factors influenced their decision to use a particular method. The top concern for participants who have not screened previously was having an invasive procedure (54.2 %) while the top concerns for participants who have screened previously were completing a colon prep (41.3 %) and test/procedure accuracy (41 %). Cost/insurance coverage was most frequently ranked among the most important attributes (48.5 %), followed by where the test can be taken (45.7 %) and test accuracy (43.6 %). Provider recommendation was reported as the major motivator across screening methods. Other factors that were frequently reported as very influential included convenience and comfort for the stool-based methods and scientific/clinical evidence and insurance coverage for colonoscopy. Variations by age, sex, and race/ethnicity were noted. Findings demonstrate that along with provider recommendation, patient preferences regarding test/procedure attributes and preparation requirements are influential in screening decision-making, highlighting the need for clinicians to involve patients in shared decision-making and incorporate patient needs and preferences in establishing screening strategies.

Factors Associated With Clinician Recommendations for Colorectal Cancer Screening Among Average-Risk Patients: Data From a National Survey.

INTRODUCTION: Colorectal cancer (CRC) screening among average-risk patients is underused in the US. Clinician recommendation is strongly associated with CRC screening completion. To inform interventions that improve CRC screening uptake among average-risk patients, we examined clinicians' routine recommendations of 7 guideline-recommended screening methods and factors associated with these recommendations. METHODS: We conducted an online survey in November and December 2019 among a sample of primary care clinicians (PCCs) and gastroenterologists (GIs) from a panel of US clinicians. Clinicians reported whether they routinely recommend each screening method, screening method intervals, and patient age at which they stop recommending screening. We also measured the influence of various factors on screening recommendations. RESULTS: Nearly all 814 PCCs (99%) and all 159 GIs (100%) reported that they routinely recommend colonoscopy for average-risk patients, followed by stool-based tests (more than two-thirds of PCCs and GIs). Recommendation of other visualization-based methods was less frequent (PCCs, 26%-35%; GIs, 30%-41%). A sizable proportion of clinicians reported guideline-discordant screening intervals and age to stop screening. Guidelines and clinical evidence were most frequently reported as very influential to clinician recommendations. Factors associated with routine recommendation of each screening method included clinician-perceived effectiveness of the method, clinician familiarity with the method, Medicare coverage, clinical capacity, and patient adherence. CONCLUSION: Clinician education is needed to improve knowledge, familiarity, and experience with guideline-recommended screening methods with the goal of effectively engaging patients in informed decision making for CRC screening.

Provider-perceived barriers to patient adherence to colorectal cancer screening.

BACKGROUND: Average-risk colorectal cancer (CRC) screening remains underutilized in the US. Provider recommendation is strongly associated with CRC screening completion. To inform interventions aimed at improving screening uptake, we examined providers' perspectives on patient and health system barriers to CRC screening adherence, along with associated system-level interventions to improve uptake. METHODS: We conducted an online survey between November and December 2019 with a sample of primary care clinicians (PCCs) and gastroenterologists (GIs) from a validated panel of US clinicians (814 PCCs, 159 GIs; completion rates: 25.3% for PCCs, 29.6% for GIs). Clinicians rated the extent to which each patient and health system factor interferes with patient adherence with CRC screening recommendations and the availability of practice interventions to improve screening rates. RESULTS: Provider-reported top barriers to CRC screening included patient discomfort with offered screening method (66%), cost (62-64%), and perceived low importance of screening (62%). Additional barriers included providers prioritizing urgent health concerns over screening (45-48%), not offering a choice of screening options (42-48%), lacking time to educate patients about screening (38-45%), and lacking education about available screening options (37-40%). Most frequently reported system-level interventions to improve CRC screening rates included patient education materials (57-62%) and point of care prompts (56-61%). Other interventions were less frequently reported, although variations existed by clinical specialty regarding barriers and interventions. CONCLUSIONS: Addressing barriers to CRC screening requires system-level interventions, including provider training on shared decision-making, automated scheduling and reminder processes, and policies to increase clinician time for preventive screening consultations.

Patient preferences on general health and colorectal cancer screening decision-making: Results from a national survey.

OBJECTIVE: We examined patient preferences regarding colorectal cancer (CRC) screening decision-making and factors associated with these preferences among screening-eligible US adults. METHODS: Through a national survey of 1595 US adults ages 40-75 (response rate: 31.3%), we measured general medical decision-making and CRC screening decision-making preferences (0-100, 100 = highest desire for involvement) and preferred control level over three CRC screening decisions (whether to screen, what method to use, and when to screen). Analyses focused on respondents aged 45-75 at average CRC risk (N = 1062). RESULTS: Respondents expressed strong desire for involvement in general medical decision-making and CRC screening decision-making (Mean = 68.1, 64.4). Over half of respondents reported preferring having equal control as their providers over whether to screen, what method to use, and when to screen. Women and people with higher education expressed higher desire for involvement in general medical decision-making. For CRC screening decision-making, variations exist in preferred level of involvement and control by race/ethnicity, educational attainment, insurance status, and recency of routine checkup. CONCLUSION: Most respondents preferred a collaborative process of CRC screening decision-making, while variations existed across subgroups. PRACTICE IMPLICATIONS: Providers should assess patients' values and preferences and involve them in CRC screening decision-making at a level they are comfortable with.

Health Care Provider Characteristics Associated With Colorectal Cancer Screening Preferences and Use.

OBJECTIVE: To assess health care provider (HCP) preferences related to colorectal cancer (CRC) screening overall, and by HCP and patient characteristics. PARTICIPANTS AND METHODS: We developed a survey based on the Theoretical Domains Framework to assess factors associated with CRC screening preferences in clinical practice. The survey was administered online November 6 through December 6, 2019, to a validated panel of HCPs drawn from US national databases and professional organizations. The final analysis sample included 779 primary care clinicians (PCCs) and 159 gastroenterologists (GIs). RESULTS: HCPs chose colonoscopy as their preferred screening method for average-risk patients (96.9% (154/159) for GIs, 75.7% (590/779) for PCCs). Among PCCs, 12.2% (95/779) preferred multi-target stool DNA (mt-sDNA), followed by fecal immunochemical test (FIT), (7.3%; 57/779) and guaiac-based fecal occult blood test (gFOBT) (4.8%; 37/779). Preference among PCCs and GIs generally shifted toward noninvasive screening options for patients who were unable to undergo invasive procedures; concerned about taking time from work; unconvinced about need for screening; and refusing other screening recommendations. Among PCCs, preference for mt-sDNA over FIT and gFOBT was less frequent in larger compared with smaller clinical practices. Additionally, preference for mt-sDNA over FIT was more likely among PCCs with more years of clinical experience, higher patient volumes (> 25/day), and practice locations in suburban and rural settings (compared to urban). CONCLUSION: Both PCCs and GIs preferred colonoscopy for CRC screening of average-risk patients, although PCCs did so less frequently and with approximately a quarter preferring stool-based tests (particularly mt-sDNA). PCCs' preference varied by provider and patient characteristics. Our findings underscore the importance of informed choice and shared decision-making about CRC screening options.

Initial validation of a self-report questionnaire based on the Theoretical Domains Framework: determinants of clinician adoption of a novel colorectal cancer screening strategy.

BACKGROUND: Colorectal cancer (CRC) screening for average risk adults age 45 and older continues to be underutilized in the USA. One factor consistently associated with CRC screening completion is clinician recommendation. Understanding the barriers and facilitators of clinical adoption of emerging CRC screening strategies is important in developing effective intervention strategies to improve CRC screening rates. We aimed to develop a questionnaire based on the Theoretical Domains Framework (TDF) to assess determinants of clinical adoption of novel CRC screening strategies, using the multi-target stool DNA test (mt-sDNA; Cologuard®) as an example, and test the psychometric properties of this questionnaire on a sample of US clinicians. METHODS: A web survey was administered between November and December 2019 to a national panel of clinicians including primary care clinicians (PCCs) and gastroenterologists (GIs) to assess 10 TDF constructs with 55 items. Confirmatory factor analysis (CFA) was used to examine whether the a priori domain structure was supported by the data. Discriminant validity of domains was tested with Heterotrait-Monotrait ratio (HTMT). Internal consistency for each scale was assessed using Cronbach's alpha. Criterion validity was assessed with self-reported mt-sDNA use and mt-sDNA recommendation as the outcomes. RESULTS: Complete surveys were received from 814 PCCs and 159 GIs (completion rate, 24.7% of 3299 PCCs and 29.6% of 538 GIs). Providers were excluded from analysis if they indicated not recommending CRC screening to average-risk patients (final N = 973). The final questionnaire consisted of 38 items covering 5 domains: (1) knowledge; (2) skills; (3) identity and social influence; (4) optimism, beliefs about consequences, and intentions; and (5) environmental context and resources. CFA results confirmed a reasonable fit (CFI = 0.948, SRMR = 0.057, RMSEA = 0.080). The domains showed sufficient discriminant validity (HTMT < 0.85), good internal consistency (McDonald's omega > 0.76), and successfully differentiated providers who reported they had ordered mt-sDNA from those who never ordered mt-sDNA and differentiated providers who reported routinely recommending mt-sDNA from those who reported not recommending mt-sDNA. CONCLUSIONS: Findings provide initial evidence for the validity and internal consistency of this TDF-based questionnaire in measuring potential determinants of mt-sDNA adoption for average-risk CRC screening. Further investigation of validity and reliability is needed when adapting this questionnaire to other novel CRC screening strategy contexts.

Barriers to utilization of three colorectal cancer screening options - Data from a national survey.

Colorectal cancer (CRC) screening continues to be underutilized in the United States. A better understanding of existing barriers is critical for improving uptake of, and adherence to, CRC screening. Using data from a population-based panel survey, we examined barriers to utilization of three commonly used screening options (FIT/gFOBT, mt-sDNA, and screening colonoscopy) and assessed differences by socio-demographic characteristics, healthcare access, and health status. Data were obtained from a questionnaire developed by the authors and implemented through a U.S. national panel survey conducted in November 2019. Among 5,097 invited panelists, 1,595 completed the survey (31.3%). Analyses were focused on individuals ages 50-75 at average risk for CRC. Results showed that among respondents who reported no prior CRC screening with FIT/gFOBT, mt-sDNA, or colonoscopy, the top barriers were lack of knowledge (FIT/gFOBT: 42.1%, mt-sDNA: 44.9%, colonoscopy: 34.7%), lack of provider recommendation (FIT/gFOBT: 32.1%, mt-sDNA: 27.3%, colonoscopy: 18.6%), and suboptimal access (FIT/gFOBT: 20.8%, mt-sDNA: 17.8%, colonoscopy: 26%). Among participants who had used one or two of the screening options, the top barriers to FIT/gFOBT and mt-sDNA were lack of provider recommendation (31.6% & 37.5%) and lack of knowledge (24.6% & 25.6%), while for colonoscopy top barriers were psychosocial barriers (31%) and lack of provider recommendation (22.7%). Differences by sex, race/ethnicity, income level, and health status were observed. Our research identified primary barriers to the utilization of three endorsed CRC screening options and differences by patient characteristics, highlighting the importance of improving CRC screening education and considering patient preferences in screening recommendations.

An examination of socioeconomic and racial/ethnic disparities in the awareness, knowledge and utilization of three colorectal cancer screening modalities.

While colorectal cancer (CRC) mortality rates have been decreasing, disparities by socioeconomic status (SES) and race/ethnicity persist. CRC screening rates remain suboptimal among low SES and racial/ethnic minority populations, despite the availability of multiple screening modalities. Understanding awareness, knowledge, and utilization of common screening modalities within different racial/ethnic and SES groups is critical to inform efforts to improve population screening uptake and reduce disparities in CRC-related health outcomes. Through the theoretical lenses of diffusion of innovation and fundamental cause theory, we examined the associations of race/ethnicity and SES with awareness, knowledge, and utilization of three guideline recommended CRC screening strategies among individuals at average risk for CRC. Data were obtained from a survey of a nationally representative panel of US adults conducted in November 2019. The survey was completed by 31.3% of invited panelists (1595 of 5097). Analyses were focused on individuals at average risk for CRC, aged 45-75 for awareness and knowledge outcomes (n = 1062) and aged 50-75 for utilization outcomes (n = 858). Analyses revealed racial/ethnic and SES disparities among the three CRC screening modalities, with more racial/ethnic and SES differences observed in the awareness, knowledge, and utilization of screening colonoscopy and mt-sDNA than FIT/gFOBT. Patterns of disparities are consistent with previous research showing that inequities in social and economic resources are associated with an imbalanced adoption of medical innovations. Our findings demonstrate a need to increase awareness, knowledge, and access of various CRC screening modalities in specific populations defined by race/ethnicity or SES indicators. Efforts to increase CRC screening should be tailored to the needs and social-cultural context of populations. Interventions addressing inequalities in social and economic resources are also needed to achieve more equitable adoption of CRC screening modalities and reduce disparities in CRC-related health outcomes.

National Survey of Patient Factors Associated with Colorectal Cancer Screening Preferences.

Recommended colorectal cancer screening modalities vary with respect to safety, efficacy, and cost. Better understanding of the factors that influence patient preference is, therefore, critical for improving population adherence to colorectal cancer screening. To address this knowledge gap, we conducted a panel survey focused on three commonly utilized colorectal cancer screening options [fecal immunochemical test or guaiac-based fecal occult blood test (FIT/gFOBT), multi-target stool DNA (mt-sDNA) test, and colonoscopy] with a national sample of U.S. adults, ages 40-75 years and at average risk of colorectal cancer, in November 2019. Of 5,097 panelists invited to participate, 1,595 completed the survey (completion rate, 31.3%). Our results showed that when presented a choice between two colorectal cancer screening modalities, more respondents preferred mt-sDNA (65.4%) over colonoscopy, FIT/gFOBT (61%) over colonoscopy, and mt-sDNA (66.9%) over FIT/gFOBT. Certain demographic characteristics and awareness of and/or experience with various screening modalities influenced preferences. For example, uninsured people were more likely to prefer stool-based tests over colonoscopy [OR, 2.53; 95% confidence interval (CI), 1.22-5.65 and OR, 2.73; 95% CI, 1.13-7.47]. People who had heard of stool-based screening were more likely to prefer mt-sDNA over FIT/gFOBT (OR, 2.07; 95% CI, 1.26-3.40). People who previously had a stool-based test were more likely to prefer FIT/gFOBT over colonoscopy (OR, 2.75; 95% CI, 1.74-4.41), while people who previously had a colonoscopy were less likely to prefer mt-sDNA or FIT/gFOBT over colonoscopy (OR, 0.39; 95% CI, 0.24-0.63 and OR, 0.40; 95% CI, 0.26-0.62). Our survey demonstrated broad patient preference for stool-based tests over colonoscopy, contrasting the heavy reliance on colonoscopy for colorectal cancer screening in clinical practice and highlighting the importance of considering patient preference in colorectal cancer screening recommendations. PREVENTION RELEVANCE: Our national survey demonstrated broad patient preference for stool-based tests over colonoscopy, contrasting the heavy reliance on colonoscopy for colorectal cancer screening in clinical practice and highlighting the importance of considering patient preference in colorectal screening recommendations.

Cross-sectional adherence with the multi-target stool DNA test for colorectal cancer screening: Real-world data from a large cohort of older adults.

OBJECTIVE: To determine cross-sectional adherence with the multi-target stool DNA test used for colorectal cancer screening in a large, fully insured Medicare population. METHODS: All patients aged 65-85 with a valid multi-target stool DNA test order from 1 September 2016 to 31 August 2017 identified from the Exact Sciences Laboratories (Madison, WI; sole-source national multi-target stool DNA test provider) database were evaluated for test adherence. Cross-sectional adherence, defined as multi-target stool DNA test completion within 365 days from order date, was analyzed overall and by time to adherence, as well as by available patient (age, sex, test order date, Medicare coverage type) and provider (specialty, year of first multi-target stool DNA test order, multi-target stool DNA test order frequency, and practice location) factors. RESULTS: Among 368,494 Medicare beneficiaries (64% female), overall cross-sectional adherence was 71%. Cumulative adherence rates increased more rapidly at 30 (44%) and 60 (65%) days, followed by more gradual increases at 90 (67%), 180 (70%), and 365 (71%) days. By provider specialty, primary care clinicians represented a higher percentage of multi-target stool DNA orders than gastroenterologists (88% vs. 6%), but had a lower associated patient adherence rate (71% vs. 78%). CONCLUSIONS: In this large, national sample of Medicare insured older adults, nearly three-quarters of patients adhered with a multi-target stool DNA order for colorectal cancer screening. These real-world data should inform further clinical and population health applications, reimbursement model simulations, and guideline-endorsed colorectal cancer screening strategies adherence.

Healthcare Provider Perspectives on Lowering Colorectal Cancer Screening Initiation Age to 45 Years: Results From a Survey of Clinicians in the U.S.

We conducted a survey of primary care clinicians and gastroenterologists (n = 938) between 11/06/19-12/06/19 to assess knowledge and attitudes regarding colorectal cancer screening. We assessed clinicians' attitudes toward lowering the colorectal cancer screening initiation age to 45 years, a topic of current debate. We also evaluated provider and practice characteristics associated with agreement. Only 38.1% of primary care clinicians endorsed colorectal cancer screening initiation at age 45 years, compared to 75.5% of gastroenterologists (p < .0001). Gastroenterologists were over 5 times more likely than primary care clinicians to endorse lowering the screening initiation age (OR = 5.30, 3.54-7.93). Other factors found to be independently associated with agreement with colorectal cancer screening initiation at age 45 years included seeing more than 25 patients per day (vs. fewer) and suburban (vs. urban) location. Results emphasize the need for collaboration between primary care clinicians and gastroenterologists to ensure that patients receive consistent messaging and evidence-based care.

Colorectal cancer screening completion: An examination of differences by screening modality.

Average-risk colorectal cancer (CRC) screening is broadly recommended, using one of several endorsed test options. However, CRC screening participation rates remain below national goals. To gain further insights regarding recent, population-based patterns in overall and test-specific CRC screening participation, we conducted a retrospective study of adults, ages 50-75 years, utilizing comprehensive data resources from the Rochester Epidemiology Project (REP). Among residents of Olmsted County, MN eligible and due for CRC screening, we identified 5818 residents across three annual cohorts who completed screening between 1/1/2016 and 12/31/2018. We summarized CRC screening rates as incidence per 1000 population and used Poisson regression to test for overall and mode-specific CRC trends. We also analyzed rates of follow-up colonoscopy within 6-months after a positive stool-based screening result. While no significant differences over time were observed in overall CRC screening incidence rates among those due for screening, we observed a statistically significant increase in mt-sDNA test and statistically significant decreases in screening colonoscopy and FIT/FOBT test completion rates; differences in screening overall and by modality were observed by age, sex, and race/ethnicity. The diagnostic colonoscopy follow-up rate within six months after a positive stool-based test was significantly higher following mt-sDNA (84.9%) compared to FIT/FOBT (42.6%). In this retrospective, population-based study, overall CRC screening incidence rates remained stable from 2016 to 2018, while test-specific rates for mt-sDNA significantly increased and decreased for colonoscopy and FIT/FOBT. Adherence with follow-up colonoscopy after a positive stool-based test was significantly higher among patients who underwent mt-sDNA screening compared to FIT/FOBT.

Invasive central venous monitoring during hepatic resection: unnecessary for most patients.

BACKGROUND: Low central venous pressure (LCVP) anesthesia reduces blood loss during hepatic resection and historically has required a central venous catheter (CVC) for intra-operative monitoring. The aim of this study was to assess the effect of an evolution of practice to CVP monitoring without CVC on the perioperative outcomes after liver resection. METHODS: A retrospective study of partial hepatectomy patients from 2007 to 2016 who were over 18 years of age was performed. RESULTS: Of 3903 patients having partial hepatectomy, 2445 (62%) met inclusion criteria, and 404 (16%) had a CVC. Overall morbidity (33% non-CVC vs 38% CVC P = 0.076), major morbidity (16% vs 20% P = 0.067), and infective complications (superficial wound infection) 3% vs 4% P = 0.429; deep wound infection (5% vs 6% P = 0.720) did not differ between the two groups. In multivariate analysis, superficial wound infection, deep wound infection, and major complications were not associated with the presence of a CVC. All-cause mortality at 90 days was associated with CVC presence (OR 3.45, CI 1.74-6.85, P = 0.001) and age (OR 1.05, CI 1.02-1.08, P < 0.001). CONCLUSION: Since the adoption of non-invasive CVP monitoring, there has been no increase in adverse peri-operative outcomes.

Weak effects of geolocators on small birds: A meta-analysis controlled for phylogeny and publication bias.

Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light-level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewed 549 records extracted from 74 published and 48 unpublished studies on over 7,800 tagged and 17,800 control individuals to examine the effects of geolocator tagging on small bird species (body mass <100 g). We calculated the effect of tagging on apparent survival, condition, phenology and breeding performance and identified the most important predictors of the magnitude of effect sizes. Even though the effects were not statistically significant in phylogenetically controlled models, we found a weak negative impact of geolocators on apparent survival. The negative effect on apparent survival was stronger with increasing relative load of the device and with geolocators attached using elastic harnesses. Moreover, tagging effects were stronger in smaller species. In conclusion, we found a weak effect on apparent survival of tagged birds and managed to pinpoint key aspects and drivers of tagging effects. We provide recommendations for establishing matched control group for proper effect size assessment in future studies and outline various aspects of tagging that need further investigation. Finally, our results encourage further use of geolocators on small bird species but the ethical aspects and scientific benefits should always be considered.

Comment on "Global pattern of nest predation is disrupted by climate change in shorebirds".

Kubelka et al (Reports, 9 November 2018, p. 680) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.

Wrangling distributed computing for high-throughput environmental science: An introduction to HTCondor.

Biologists and environmental scientists now routinely solve computational problems that were unimaginable a generation ago. Examples include processing geospatial data, analyzing -omics data, and running large-scale simulations. Conventional desktop computing cannot handle these tasks when they are large, and high-performance computing is not always available nor the most appropriate solution for all computationally intense problems. High-throughput computing (HTC) is one method for handling computationally intense research. In contrast to high-performance computing, which uses a single "supercomputer," HTC can distribute tasks over many computers (e.g., idle desktop computers, dedicated servers, or cloud-based resources). HTC facilities exist at many academic and government institutes and are relatively easy to create from commodity hardware. Additionally, consortia such as Open Science Grid facilitate HTC, and commercial entities sell cloud-based solutions for researchers who lack HTC at their institution. We provide an introduction to HTC for biologists and environmental scientists. Our examples from biology and the environmental sciences use HTCondor, an open source HTC system.

Delayed egg-laying and shortened incubation duration of Arctic-breeding shorebirds coincide with climate cooling.

Biological impacts of climate change are exemplified by shifts in phenology. As the timing of breeding advances, the within-season relationships between timing of breeding and reproductive traits may change and cause long-term changes in the population mean value of reproductive traits. We investigated long-term changes in the timing of breeding and within-season patterns of clutch size, egg volume, incubation duration, and daily nest survival of three shorebird species between two decades. Based on previously known within-season patterns and assuming a warming trend, we hypothesized that the timing of clutch initiation would advance between decades and would be coupled with increases in mean clutch size, egg volume, and daily nest survival rate. We monitored 1,378 nests of western sandpipers, semipalmated sandpipers, and red-necked phalaropes at a subarctic site during 1993-1996 and 2010-2014. Sandpipers have biparental incubation, whereas phalaropes have uniparental incubation. We found an unexpected long-term cooling trend during the early part of the breeding season. Three species delayed clutch initiation by 5 days in the 2010s relative to the 1990s. Clutch size and daily nest survival showed strong within-season declines in sandpipers, but not in phalaropes. Egg volume showed strong within-season declines in one species of sandpiper, but increased in phalaropes. Despite the within-season patterns in traits and shifts in phenology, clutch size, egg volume, and daily nest survival were similar between decades. In contrast, incubation duration did not show within-season variation, but decreased by 2 days in sandpipers and increased by 2 days in phalaropes. Shorebirds demonstrated variable breeding phenology and incubation duration in relation to climate cooling, but little change in nonphenological components of traits. Our results indicate that the breeding phenology of shorebirds is closely associated with the temperature conditions on breeding ground, the effects of which can vary among reproductive traits and among sympatric species.

Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds.

BACKGROUND: Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8-2.0 g total, representing 0.1-3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2-4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26-1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables. RESULTS: We detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to negatively affect return rates if the total mass of geolocators and color markers was 2.5-5.8 % of body mass than if tags were 0.3-2.3 % of body mass. Carrying a geolocator reduced nest success by 42 % for semipalmated sandpipers and tripled the probability of partial clutch failure in semipalmated and western sandpipers. Geolocators mounted perpendicular to the leg on a flag had stronger negative effects on nest success than geolocators mounted parallel to the leg on a band. However, parallel-band geolocators were more likely to reduce return rates and cause injuries to the leg. No effects of geolocators were found on breeding movements or changes in body mass. Among-site variation in geolocator effect size was high, suggesting that local factors were important. CONCLUSIONS: Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional markers. Investigators could maximize recovery of tags by strategically deploying geolocators on males, previously marked individuals, and successful breeders, though targeting subsets of a population could bias the resulting migratory movement data in some species.

Unexpected positive and negative effects of continuing inbreeding in one of the world's most inbred wild animals.

Inbreeding depression, the reduced fitness of offspring of related individuals, is a central theme in evolutionary biology. Inbreeding effects are influenced by the genetic makeup of a population, which is driven by any history of genetic bottlenecks and genetic drift. The Chatham Island black robin represents a case of extreme inbreeding following two severe population bottlenecks. We tested whether inbreeding measured by a 20-year pedigree predicted variation in fitness among individuals, despite the high mean level of inbreeding and low genetic diversity in this species. We found that paternal and maternal inbreeding reduced fledgling survival and individual inbreeding reduced juvenile survival, indicating that inbreeding depression affects even this highly inbred population. Close inbreeding also reduced survival for fledglings with less-inbred mothers, but unexpectedly improved survival for fledglings with highly inbred mothers. This counterintuitive interaction could not be explained by various potentially confounding variables. We propose a genetic mechanism, whereby a highly inbred chick with a highly inbred parent inherits a "proven" genotype and thus experiences a fitness advantage, which could explain the interaction. The positive and negative effects we found emphasize that continuing inbreeding can have important effects on individual fitness, even in populations that are already highly inbred.

Simulating retention of rare alleles in small populations to assess management options for species with different life histories.

Preserving allelic diversity is important because it provides the capacity for adaptation and thus enables long-term population viability. Allele retention is difficult to predict in animals with overlapping generations, so we used a new computer model to simulate retention of rare alleles in small populations of 3 species with contrasting life-history traits: North Island Brown Kiwi (Apteryx mantelli; monogamous, long-lived), North Island Robins (Petroica longipes; monogamous, short-lived), and red deer (Cervus elaphus; polygynous, moderate lifespan). We simulated closed populations under various demographic scenarios and assessed the amounts of artificial immigration needed to achieve a goal of retaining 90% of selectively neutral rare alleles (frequency in the source population = 0.05) after 10 generations. The number of immigrants per generation required to meet the genetic goal ranged from 11 to 30, and there were key similarities and differences among species. None of the species met the genetic goal without immigration, and red deer lost the most allelic diversity due to reproductive skew among polygynous males. However, red deer required only a moderate rate of immigration relative to the other species to meet the genetic goal because nonterritorial breeders had a high turnover. Conversely, North Island Brown Kiwi needed the most immigration because the long lifespan of locally produced territorial breeders prevented a large proportion of immigrants from recruiting. In all species, the amount of immigration needed generally decreased with an increase in carrying capacity, survival, or reproductive output and increased as individual variation in reproductive success increased, indicating the importance of accurately quantifying these parameters to predict the effects of management. Overall, retaining rare alleles in a small, isolated population requires substantial investment of management effort. Use of simulations to explore strategies optimized for the populations in question will help maximize the value of this effort..