Assessing the Consequences of Brood Parasitism and Nest Predation On Seasonal Fecundity in Passerine Birds

Brood parasites and nest predators reduce the seasonal fecundity and, hence, the population growth rates of their victims. However, most field studies do not measure directly how parasites and predators decrease seasonal fecundity, but instead measure the impact of these organisms on individual nesting attempts. Because a female may renest after losing a nest to predation, abandoning a parasitized nest, or successfully fledging a brood, knowing how brood parasites and nest predators reduce the number of offspring fledged from individual nesting attempts is not equivalent to knowing their impact on seasonal fecundity. We address this problem by developing a mathematical model that: estimates several parameters describing the natural history of this system, including the brood-parasitism rate, nest-predation rate, and probability of nest abandonment in response to a parasitism event; and extrapolates to seasonal fecundity from these parameters and others describing the length of the breeding season, the timing of events in the nesting cycle, and the productivity of parasitized and unparasitized nests. We also show how different researchers using different observational methodologies to study exactly the same population likely would arrive at noticeably different conclusions regarding the intensity of brood parasitism, and we provide mathematical formulas for comparing among several of these measures of parasitism. Our procedures extend Mayfield's method for calculating nest-success rates from nest-history data in that we simultaneously estimate parameters describing nest predation and brood parasitism, predict seasonal fecundity from these parameters, and provide confidence intervals on all parameter estimates. The model should make the design and interpretation of logistically difficult empirical studies more efficient. It also can be specialized to species affected by nest predators but not brood parasites. We use the model to analyze prairie Warbler (Dendroica discolor) and Black-capped Vireo (Vireo atricapillus) nesting data. We estimate the model's parameters for these species and use the resulting estimates to predict seasonal fecundity. For both species, the predicted seasonal fecundity closely matches the value measured directly.Integrative Biolog

Short-Lived Trace Gases in the Surface Ocean and the Atmosphere

The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science

Grand Challenges in global eye health: a global prioritisation process using Delphi method

Background We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods Drawing on methods used in previous Grand Challenges studies, we used a multi-step recruitment strategy to assemble a diverse panel of individuals from a range of disciplines relevant to global eye health from all regions globally to participate in a three-round, online, Delphi-like, prioritisation process to nominate and rank challenges in global eye health. Through this process, we developed both global and regional priority lists. Findings Between Sept 1 and Dec 12, 2019, 470 individuals complete round 1 of the process, of whom 336 completed all three rounds (round 2 between Feb 26 and March 18, 2020, and round 3 between April 2 and April 25, 2020) 156 (46%) of 336 were women, 180 (54%) were men. The proportion of participants who worked in each region ranged from 104 (31%) in sub-Saharan Africa to 21 (6%) in central Europe, eastern Europe, and in central Asia. Of 85 unique challenges identified after round 1, 16 challenges were prioritised at the global level; six focused on detection and treatment of conditions (cataract, refractive error, glaucoma, diabetic retinopathy, services for children and screening for early detection), two focused on addressing shortages in human resource capacity, five on other health service and policy factors (including strengthening policies, integration, health information systems, and budget allocation), and three on improving access to care and promoting equity. Interpretation This list of Grand Challenges serves as a starting point for immediate action by funders to guide investment in research and innovation in eye health. It challenges researchers, clinicians, and policy makers to build collaborations to address specific challenge

Black-Capped Vireo Recovery Plan

Current Species Status: This species is listed as endangered. The number of individuals is unknown. However, it has undergone substantial range reduction in Kansas, Oklahoma, and Texas. It is extirpated in Kansas, and the Oklahoma population is below 300 birds. Declines have also been documented over much of the species’ range in Texas. Its status is uncertain in Coahuila, Mexico. Habitat Requirements and Limiting Factors: The black-capped vireo occurs in mixed deciduous/evergreen shrubland. Breeding vireos use shrubby growth of irregular height and distribution with spaces between the small thickets and clumps and with vegetative cover extending to ground level. Habitat losses are occurring through development, over-browsing, and suppression and alteration of natural disturbance regimes. Cowbird nest parasitism has been drastically reducing vireo reproduction in many areas. Recovery Objective: Downlisting Recovery Criteria: All existing populations are to be protected and stabilized; and at least one viable breeding population (of at least 500 to 1,000 breeding pairs each) should exist in each of six regions, including one in Oklahoma, one in Mexico, and four in Texas; and sufficient and sustainable area should exist to support the birds when they are on their winter range; and all of the previously mentioned criteria should have been maintained for at least 5 consecutive years and assurance should exist that they will continue to be maintained. Threats from habitat loss, cowbird parasitism, and other factors will need to be resolved. Actions Needed: 1. Additional surveys. 2. Clarify population size, area requirements, and location needs for viable populations. 3. Maintain viable populations in target areas. 4. Conduct research On species’ biology, habitat needs and management, threats, and winter range. 5. Eliminate threats from cowbird nest parasitism, habitat deterioration, and other agents. 6. Develop and conduct a program for monitoring the vireo’s status