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A bird watcher's guide to wrens
\"The fat bundle of feathers called the house wren is a cute bird. It often cheerfully trills its sweet songs. However, this little fowls mood can turn really foul when another bird has a nesting site it wants! It may peck at larger birds to get them to moveand even push eggs out of a nest. Readers of this absorbing book will find that, with all kinds of wrens, looks can be deceiving. They'll love the diverting narrative and fun fact boxes and especially the up-close look at wrens in their native habitats\"-- Provided by publisher.
Book
St Paul's Cathedral
This is the first volume concerned solely with the archaeology of a major late 17th century building in London, and the major changes it has undergone. St Paul’s Cathedral in the City of London was built in 1675–1711 to the designs of Sir Christopher Wren and has been described as an iconic building many times. In this major new account, John Schofield examines the cathedral from an archaeological perspective, reviewing its history from the early 18th to the early 21st century, as illustrated by recent archaeological recording, documentary research and engineering assessment. A detailed account of the construction of the cathedral is provided based on a comparison of the fabric with voluminous building accounts which have survived and evidence from recent archaeological investigation. The construction of the Wren building and its embellishments are followed by the main works of later surveyors such as Robert Mylne and Francis Penrose. The 20th century brought further changes and conservation projects, including restoration after the building was hit by two bombs in World War II, and all its windows blown out. The 1990s and first years of the present century have witnessed considerable refurbishment and cleaning involving archaeological and engineering works. Archaeological specialist reports and an engineering review of the stability and character of the building are provided.
eBook
GENOMIC AND MORPHOLOGICAL ANALYSIS OF A SEMIPERMEABLE AVIAN HYBRID ZONE SUGGESTS ASYMMETRICAL INTROGRESSION OF A SEXUAL SIGNAL
Hybrid zones are geographic regions where differentiated taxa meet and potentially exchange genes. Increasingly, genomic analyses have demonstrated that many hybrid zones are semipermeable boundaries across which introgression is highly variable. In some cases, certain alleles penetrate across the hybrid zone in only one direction, recombining into the alternate genome. We investigated this phenomenon using genomic (genotyping-by-sequencing) and morphological (plumage reflectance spectrophotometry) analyses of the hybrid zone between two subspecies of the red-backed fairy-wren (Malurus melanocephalus) that differ conspicuously in a sexual signal, male back plumage color. Geographic cline analyses revealed a highly variable pattern of differential introgression, with many narrow coincident clines combined with several significantly wider clines, suggesting that the hybrid zone is a semipermeable tension zone. The plumage cline was shifted significantly into the genomic background of the orange subspecies, consistent with sexual selection driving asymmetrical introgression of red plumage alleles across the hybrid zone. This interpretation is supported by previous experimental work demonstrating an extra-pair mating advantage for red males, but the role of genetic dominance in driving this pattern remains unclear. This study highlights the potential for sexual selection to erode taxonomic boundaries and promote gene flow, particularly at an intermediate stage of divergence.
Journal Article
Overlapping home ranges and microhabitat partitioning among Canyon Wrens
Patterns of animal space use may vary according to species identity, presence of conspecifics, presence of heterospecifics, and resource availability. We evaluated joint space use by Canyon Wrens (Catherpes mexicanus) and Rock Wrens (Salpinctes obsoletus) by comparing home range sizes, home range overlap, and foraging behavior. Canyon and Rock wrens are ecologically similar species which frequently co-occur along rocky cliffs where members of both species feed on terrestrial invertebrates. Interactions between Canyon and Rock wrens provide information about avian space use and foraging strategies in understudied cliff habitats. We estimated home range for each species using ArcGIS, and quantified foraging microhabitat use. Canyon Wren home ranges were widely spaced, did not overlap conspecifics, and were significantly larger than those of Rock Wrens. Rock Wrens occurred at higher densities and home ranges overlapped conspecifics in 33% of cases by an average of 19%. Canyon and Rock wren home ranges overlapped in 68% of cases by an average of 28%, but overlapping pairs rarely shared core use areas. The two species differed significantly in foraging microhabitat use. Results suggest that heterospecific territory defense between Canyon and Rock wrens is low, and that these species have adopted different methods for using shared resources in escarpment and cliff habitats. Received 25 November 2014. Accepted 27 February 2015.
Journal Article
Modeling variability in the fire response of an endangered bird to improve fire-management
Conservation managers regularly burn vegetation to regenerate habitat for fire-dependent species. When determining the time since fire at which to burn, managers model change in a species’ occurrence over time, post-fire (fire-response curve) and identify the time since fire associated with decline in occurrence. However, where species exhibit variability in their fire response across space, using a single fire-response curve to determine the timing of burns may lead to burning habitat at an inappropriate time since fire. We tested if elevation, local topography, soil properties, vegetation type or evapotranspiration affect the fire response of the endangered Mallee Emu-wren Stipiturus mallee and its hummock-grass habitat Triodia scariosa in southeastern Australia (n = 217). Previous work on the Mallee Emu-wren found a unimodal fire response with decline in occurrence at ~30–50 yr since fire and a time window of occurrence of ~30 yr. We found that time since fire and elevation interact to affect the Mallee Emu-wren fire response. At high elevations (55–98 m), Mallee Emu-wrens declined in occurrence at ~50 yr since fire, with a time window of occurrence of 20–40 yr. However, at low elevations (28–55 m), Mallee Emu-wrens showed no decline in occurrence with increasing time since fire with a time window of occurrence of up to 107 yr. Extent cover of Tall T. scariosa showed similar patterns to the Mallee Emu-wren, indicating that vegetation structure is a likely driver of variability in the Mallee Emu-wren fire response. We speculate that the effect of low elevation is mediated by increased soil nutrient and water availability for key plants. We used our findings to map the appropriate time since fire at which to burn to regenerate habitat for the Mallee Emu-wren across the study region. We recommend no burning for regeneration across one-third of potential habitat, because the Mallee Emu-wren showed no decline in occurrence in these areas. We recommend managers model variability in species’ fire responses across space to improve the timing of burns for regeneration.
Journal Article
Effects of Anthropogenic Habitat Fragmentation on the Genetic Connectivity of the Threatened and Endemic ICampylorhynchus yucatanicus/I in the Yucatan Peninsula, Mexico
Identifying connectivity patterns among remnant bird populations and their relationships with land use practices and adjacent habitat fragments is key to implementing appropriate long-term management strategies for species conservation. The coastal scrub and dune vegetation complex of the northern Yucatan Peninsula is rich in endemisms and has been affected by human development, which threatens the survival of the Yucatan Wren (Campylorhynchus yucatanicus) population, an endemic bird species. To identify possible anthropogenic barriers to the connectivity of C. yucatanicus along 14 localities in the Yucatan (Mexico) coastal north, we explored the relationship between the species population’s genetic variability at each sampled site and landscape structure using regression models, in addition to the relationship between genetic distance and landscape resistance. Seven nuclear microsatellite loci were used as genetic markers. Four genetic populations were highlighted by the clustering method implemented in the Geneland program. Human settlement and availability of adequate habitat were significantly related to genetic distance (Fst), suggesting limited connectivity among sites due to ongoing land use changes. We suggest changing the IUCN threat category of C. yucatanicus to endangered as we found a significant loss of genetic variability in addition to restricted distribution, small population, habitat degradation, and loss of connectivity.
Journal Article
No effect of testosterone or sexual ornamentation on telomere dynamics: A case study and meta‐analyses
Life‐history theory predicts that reproductive investments are traded‐off against self‐maintenance. Telomeres, the protective caps on the ends of chromosomes, offer a promising avenue for assessing life‐history trade‐offs, as they shorten in response to stressors and are predictive of the remaining lifespan. In males, testosterone frequently mediates life‐history trade‐offs, in part, through its effects on sexual ornamentation, which is an important aspect of reproductive investment. However, studies of within‐individual associations between telomere dynamics and sexual ornamentation are limited in number and have produced mixed results. Furthermore, most such studies have been observational, making it difficult to discern the nature of any causal relationship. To address this, we used short‐acting testosterone implants in free‐living male superb fairy‐wrens (Malurus cyaneus) to stimulate the production of a sexual ornament: early moult into a costly blue breeding plumage. We found no evidence that elevated testosterone, and the consequent earlier moult into breeding plumage, accelerated telomere shortening. We therefore followed up with a systematic review and two meta‐analyses (28 studies, 54 effect sizes) exploring the associations between telomeres and (1) testosterone and (2) sexual ornamentation. In line with our experimental findings, neither meta‐analysis showed an overall correlation of testosterone or sexual ornamentation with telomere length or telomere dynamics. However, meta‐regression showed that experimental, compared to observational, studies reported greater evidence of trade‐offs. Our meta‐analyses highlight the need for further experimental studies to better understand potential responses of telomere length or telomere dynamics to testosterone or sexual ornamentation. Telomeres, the protective caps on the ends of chromosomes, offer a promising avenue for assessing life‐history trade‐offs, as they shorten in response to stressors and are predictive of the remaining lifespan. In addition to carrying out an experimental case study on a free‐living songbird, we conducted a systematic review and two meta‐analyses (28 studies, 54 effect sizes) exploring the associations between telomeres and (1) testosterone and (2) sexual ornamentation. In line with the findings of our case study, neither meta‐analysis showed an overall correlation of testosterone or sexual ornamentation with telomere length or telomere dynamics.
Journal Article
Improved Superb Fairy-Wren Optimization Algorithm and Its Application
The Superb Fairy-wren Optimization Algorithm (SFOA) is a meta-heuristic algorithm inspired by the behavior of the superb fairy-wren. However, the conventional SFOA tends to converge to local optima and exhibits limited convergence accuracy when addressing complex optimization problems. To overcome these drawbacks, this study proposes an Improved Superb Fairy-wren Optimization Algorithm (ISFOA). The ISFOA incorporates four strategies—Chebyshev chaotic mapping, an adaptive weighting factor, Cauchy–Gaussian mutation, and t-distribution perturbation—to enhance the algorithm’s ability to balance global exploration and local exploitation. An ablation study using the CEC 2021 test suite was performed to evaluate the individual contribution of each strategy. Moreover, to comprehensively assess the performance of ISFOA, a comparative analysis was carried out against eight other meta-heuristic algorithms on both the CEC2005 and CEC2021 benchmark function sets. Additionally, the practical applicability of ISFOA was examined by comparing it with eight other optimization algorithms across seven engineering design problems. The comprehensive experimental results indicate that ISFOA outperforms the original SFOA and other compared algorithms in terms of robustness and convergence accuracy, thereby offering an efficient and reliable approach for solving complex optimization problems.
Journal Article
PROMISCUITY DRIVES SEXUAL SELECTION IN A SOCIALLY MONOGAMOUS BIRD
Many socially monogamous species paradoxically show signs of strong sexual selection, suggesting cryptic sources of sexual competition among males. Darwin argued that sexual selection could operate in monogamous systems if breeding sex ratios are biased or if some males attract highly fecund females. Alternatively, sexual selection might result from promiscuous copulations outside the pair bond, although several recent studies have cast doubt on this possibility, in particular by showing that variance in apparent male reproductive success (number of social young) differs little from variance in actual male reproductive success (number of young sired). Our results from a long-term study of the socially monogamous splendid fairy-wren (Malurus splendens) demonstrate that such comparisons are misleading and do not adequately assess the effects of extra-pair paternity (EPP). By partitioning the opportunity for selection and calculating Bateman gradients, we show that EPP has a strong effect on male annual and lifetime fitness, whereas other proposed mechanisms of sexual selection do not. Thus, EPP drives sexual selection in this, and possibly other, socially monogamous species.
Journal Article