Influence of Season and Time of Day on Marsh Bird Detections

Call-broadcast surveys are frequently used to elicit responses of secretive marsh birds and produce greater detection rates than passive surveys. However, little is known about how detection rates of birds from these surveys differ by season and time of day. We conducted call-broadcast surveys for eight focal species at 56 wetlands throughout Iowa from 15 May–13 June 2010 (early season) and from 15 June–10 July 2010 (late season). Our focal species were Pied-billed Grebe (Podilymbus podiceps), American Bittern (Botaurus lentiginosus), Least Bittern (Ixobrychus exilis), King Rail (Rallus elegans), Virginia Rail (Rallus limicola), Sora (Porzana carolina), Common Gallinule (Gallinula chloropus), and American Coot (Fulica americana). Surveys were conducted in the early morning (30 mins before sunrise to 3 hrs after sunrise) and late evening (3 hrs before sunset to 30 mins after sunset) in accordance with the North American Marsh Bird Monitoring Protocol. We evaluated marsh bird detection rates as a function of a) time of day (morning and evening survey periods), b) season (early and late in the breeding season), and c) wetland size for four species with the greatest detection rates (Pied-billed Grebe, Least Bittern, Virginia Rail, and Sora). We also evaluated the above effects for two species groups; all eight species pooled and all rails pooled. We found significant (P \u3c 0.05) effects on the number of detections for Pied-billed Grebe in response to time of day, time of season, and wetland size; Sora, Virginia Rail, all rails, and all species had an effect of time of season only. Understanding seasonal and time-of-day differences in detection rates, as well as area dependence of secretive marsh birds, will refine existing monitoring protocols by allowing researchers to maximize detection probabilities of target species

Density and Abundance of Secretive Marsh Birds in Iowa

A decrease in wetland habitats throughout North America has caused a decline in populations of marsh birds. The objective of this study was to estimate population densities and abundances of secretive marsh birds in Iowa. Call-broadcast surveys were conducted in conjunction with distance sampling for eight species of marsh birds at wetlands in three regions of Iowa during 2009 and 2010. Regions were defined by observed microhabitat characteristics which also corresponded to physiographic regions. Region-specific density estimates were obtained using Program Distance for four species of marsh birds for which sufficient detections existed (Pied-billed Grebe [Podilymbus podiceps], Least Bittern [Ixobrychus exilis], Virginia Rail [Rallus limicola] and Sora [Porzana carolina]). The range of density estimates was 0.019 birds/ha (95% CI = 0.014-0.024) for Least Bittern to 0.12 birds/ha (95% CI = 0.11-0.14) for Pied-billed Grebe. Density estimates were highest in Region 2 for Pied-billed Grebe, Region 1 for Virginia Rail, and Region 3 for Sora. Least Bittern density was similar between Regions 1 and 2, but was 0.027 birds/ha lower in Region 3. The need to focus conservation efforts on areas of the state where large amounts of suitable habitat exist and marsh bird densities are highest is illustrated by the observed differences in species\u27 densities across regions. Information on the current population status of marsh birds in Iowa and regions where conservation efforts can be directed are provided by these density estimates

Density, Abundance, and Habitat Associations of the Inland Swamp Sparrow (Melospiza georgiana georgiana) in Iowa

Wetlands continue to decline throughout North America and the Prairie Pothole Region, thus emphasizing the importance of understanding population trends and habitat associations of wetland species to ensure effective conservation and habitat management of those species. We estimated density and abundance and evaluated habitat associations of the Inland Swamp Sparrow (Melospiza georgiana georgiana) in Iowa. We conducted standardized distance sampling surveys for Swamp Sparrows and measured habitat characteristics at 307 wetlands in two regions of Iowa in 2009 and 2010. We used Program Distance to model detection probability and estimate region-specific breeding densities of Swamp Sparrows at Iowa wetlands. We then extrapolated density estimates to the total area of wetlands in each region to obtain estimates of breeding abundance. We correlated Swamp Sparrow counts to nine habitat variables using Poisson regression in Program R. Swamp Sparrow counts were positively correlated with percent cover of cattail (Typha spp.) and water depth (cm) and negatively correlated with percent cover of woody vegetation, vegetation size (m), and wetland size (ha). We estimated breeding densities of Swamp Sparrows to be 1.488 birds/ha (95% CI = 1.308 − 1.692) in region 1 (Des Moines Lobe landform) and 0.041 birds/ha (95% CI = 0.006 − 0.275) in region 2 (remainder of the state). Our results, in comparison to those of other studies, indicate that Swamp Sparrows associate with a variety of wetland characteristics depending upon what is available. Swamp Sparrows are relatively uncommon breeders in Iowa, and our work confirms that most occur in the Des Moines Lobe landform in north-central and northwestern Iowa. Biologists and land managers should incorporate our findings on this species’ habitat associations into management activities to ensure that Swamp Sparrow populations persist into the future

First Record of a Comb Duck (Sarkidiornis melanotos sulvicola) for Costa Rica

The authors, in company with Rafael Ramirez and a group of Iowa State University students, observed, photographed, and documented a male Comb Duck of the South American subspecies (Sarkidiornis melanotos sylvicola) at the large drying wetland in Palo Verde National Park, Costa Rica on 18 March 2010. The bird was present the following day and last reported 25 March 2010. The record is supported by photographs and becomes the first for Costa Rica and northernmost in the Western Hemisphere

The Eroding Artificial/Natural Distinction: Some Consequences for Ecology and Economics

Since Thomas Kuhn’s The Structure of Scientific Revolutions (1962), historians and philosophers of science have paid increasing attention to the implications of disciplinarity. In this chapter we consider restrictions posed to interdisciplinary exchange between ecology and economics that result from a particular kind of commitment to the ideal of disciplinary purity, that is, that each discipline is defined by an appropriate, unique set of objects, methods, theories, and aims. We argue that, when it comes to the objects of study in ecology and economics, ideas of disciplinary purity have been underwritten by the artificial-natural distinction. We then problematize this distinction, and thus disciplinary purity, both conceptually and empirically. Conceptually, the distinction is no longer tenable. Empirically, recent interdisciplinary research has shown the epistemological and policy-oriented benefits of dealing with models which explicitly link anthropogenic (i.e., “artificial”) and non-anthropogenic factors (i.e., “natural”). We conclude that, in the current age of the Anthropocene, it is to be expected that without interdisciplinary exchange, ecology and economics may relinquish global relevance because the distinct and separate systems to which each “pure” science was originally made to apply will only diminish over time

Implementing the three-particle quantization condition including higher partial waves

We present an implementation of the relativistic three-particle quantization condition including both $s$- and $d$-wave two-particle channels. For this, we develop a systematic expansion about threshold of the three-particle divergence-free K matrix, $\mathcal{K}_{\mathrm{df,3}}$, which is a generalization of the effective range expansion of the two-particle K matrix, $\mathcal{K}_2$. Relativistic invariance plays an important role in this expansion. We find that $d$-wave two-particle channels enter first at quadratic order. We explain how to implement the resulting multichannel quantization condition, and present several examples of its application. We derive the leading dependence of the threshold three-particle state on the two-particle $d$-wave scattering amplitude, and use this to test our implementation. We show how strong two-particle $d$-wave interactions can lead to significant effects on the finite-volume three-particle spectrum, including the possibility of a generalized three-particle Efimov-like bound state. We also explore the application to the $3\pi^+$ system, which is accessible to lattice QCD simulations, where we study the sensitivity of the spectrum to the components of $\mathcal{K}_{\mathrm{df,3}}$. Finally, we investigate the circumstances under which the quantization condition has unphysical solutions.Comment: 57 pages, 12 figures, 3 tables (v2: Made minor clarifications, updated a reference, fixed typos

A Point of Order

Paper by Stephen A. Tyle

Bound to Aim at Good Generally: A Sidgwickian Argument for Rational Impartialism

In this dissertation I defend an unorthodox theory of practical reason called Rational Impartialism. According to this view, one ought to have equal fundamental concern for the equal good of everyone. Central to my argument for Rational Impartialism are two of Henry Sidgwick’s axioms of ethics. According to the axiom of Equal Good, one ought to have equal fundamental concern for equal portions of the good. According to the axiom of Personal Irrelevance, the equal good of any two individuals is exactly similar qua portions of universal good. Sidgwick claims that from these two axioms we can deduce a principle of benevolence which is essentially the view I call Rational Impartialism. However, there are three problems with this deduction: (1) an egoist can accept the axioms but resist impartialism by insisting that ‘good’ is agent-relative, (2) if partiality towards loved ones is itself part of the good, then adherence to the axioms could be compatible with having ultimate reasons of partiality, (3) disagreement over the axiom of Equal Good seems to undermine its usefulness as a foundational ethical premise. I attempt to revive Sidgwick’s derivation of Rational Impartialism by responding to all three challenges

Entry-Level Cognitive Mathematics Skill and First-Semester Mathematics Performance as Correlates of Fall-to-Fall Retention of Community College Students

The purpose of this study was to investigate the relationship between first-semester mathematics performance and fall-to-fall retention for first-time-in-college, degree-seeking community college students. The study further refined the investigation by seeking to determine if the significance of this relationship was affected by student readiness for college-level mathematics as of the first semester of enrollment at the institution under study. The sample chosen for this study consisted of 1518 first-time-in-college, degree-seeking students enrolled in fall semester 2011 at a large, multi-campus community college in Virginia. The dependent variable was fall-to-fall retention, a commonly applied student success metric in the Virginia Community College System. The primary independent variable, first-semester mathematics performance, was tripartite, with each student having either enrolled in and successfully completed a first-semester mathematics course, enrolled in but failed to complete a first-semester mathematics course successfully, or deferred enrollment in mathematics until after the first semester. Quantitative statistical analysis was applied to determine the significance of the relationship between these variables within each of the subgroups and demographic constituencies. The study found that, regardless of readiness level, students who enrolled in and successfully completed a first-semester mathematics course experienced a fall-to-fall retention rate nearly 20% higher than that experienced by the sample taken as a whole. Meanwhile students who were unsuccessful in a first-semester mathematics class, as well as those who deferred enrollment in mathematics, experienced retention rates approximately I0% lower than that experienced by the sample overall. The study concluded that successful, first-semester enrollment in mathematics portends significantly higher fall-to-fall retention rates for degree-seeking students. However, disturbingly low success rates in both college-level and developmental-level mathematics courses suggest that first-semester enrollment in mathematics is a high-risk strategy for improving retention