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Dear Helen : wartime letters from a Londoner to her American pen pal
\"In letters written between 1937 and 1950 to her American pen pal, a working-class Londoner offers accounts of the Blitz and of wartime deprivations and postwar austerity, interweaving descriptions of terror with talk about theater, clothes, and family outings, providing a unique view of daily life during World War II\"--Provided by publisher.
Book
The Mitogenome Relationships and Phylogeography of Barn Swallows (Hirundo rustica)
The barn swallow (Hirundo rustica) poses a number of fascinating scientific questions, including the taxonomic status of postulated subspecies. Here, we obtained and assessed the sequence variation of 411 complete mitogenomes, mainly from the European H. r. rustica, but other subspecies as well. In almost every case, we observed subspecies-specific haplogroups, which we employed together with estimated radiation times to postulate a model for the geographical and temporal worldwide spread of the species. The female barn swallow carrying the Hirundo rustica ancestral mitogenome left Africa (or its vicinity) around 280 thousand years ago (kya), and her descendants expanded first into Eurasia and then, at least 51 kya, into the Americas, from where a relatively recent (<20 kya) back migration to Asia took place. The exception to the haplogroup subspecies specificity is represented by the sedentary Levantine H. r. transitiva that extensively shares haplogroup A with the migratory European H. r. rustica and, to a lesser extent, haplogroup B with the Egyptian H. r. savignii. Our data indicate that rustica and transitiva most likely derive from a sedentary Levantine population source that split at the end of the Younger Dryas (YD) (11.7 kya). Since then, however, transitiva received genetic inputs from and admixed with both the closely related rustica and the adjacent savignii. Demographic analyses confirm this species’ strong link with climate fluctuations and human activities making it an excellent indicator for monitoring and assessing the impact of current global changes on wildlife.
Journal Article
Spectra of feather samples are impacted by the substrate color against which they are measured/Los espectros de plumas muestreadas son afectados por el color del sustrato contra el cual se miden
Many studies of animal and plumage coloration use spectrometry to obtain objective measurements of colorful traits. Objective measurements of plumage color are particularly important as the avian visual system is distinct from our own and subjective color assessment by researchers can miss important color variation or signals. As spectrometry has become one of the preferred methods of color measurement, appropriate methodologies and reporting standards have refined and improved the technique as well as increased our ability to make comparisons across studies. Here, we investigate another important methodological decision by examining how the background color against which feather samples are measured impacts the reflectance spectra and color descriptors commonly extracted from those spectra. We used feather samples collected from Eastern Bluebirds (Sicilia siulis) and Barn Swallows (Hirundo rustica erythrogaster) to determine how black and white backgrounds influence color measurements. We measured the same feather sample in the same arrangement against a white index card and a piece of black cardstock and found that measurements taken against a white background tended to yield higher reflectance curves, which also resulted in significant differences in some color descriptors. Lightly colored, wispy, and small feathers seem to be particularly susceptible to background color effects. Thus, researchers using spectrometry to measure colorful traits should carefully consider the background against which they are taking measurements as white backgrounds tend to increase reflectance and certain feather colors or morphology (light and wispy) may be particularly susceptible to spectral contamination. Received 26 May 2022. Accepted 28 December 2022.
Journal Article
Environmental conditions during early life accelerate the rate of senescence in a short-lived passerine bird
Environmental conditions experienced in early life may shape subsequent phenotypic traits including life history. We investigated how predation risk caused by domestic cats (
Felis silvestris catus
) and local breeding density affected patterns of reproductive and survival senescence in Barn Swallows (
Hirundo rustica
) breeding semicolonially in Denmark. We recorded the abundance of cats and the number of breeding pairs at 39 breeding sites during 24 years and related these to age-specific survival rate and reproductive senescence to test predictions of the life history theory of senescence. We found evidence for actuarial senescence for the first time in this species. Survival rate increased until reaching a plateau in midlife and then decreased later. We also found that survival rate was higher for males than females. Local breeding density or predation risk did not affect survival as predicted by theory. Barn Swallows with short lives did not invest more in reproduction in early life, inconsistent with expectations for trade-offs between reproduction and survival as theory suggests. However, we found that the rate of reproductive decline during senescence was steeper for individuals exposed to intense competition, and predation pressure accelerated the rate of reproductive senescence, but only in sites with many breeding pairs. These latter results are in accordance with one of the predictions suggested by the life history theory of aging. These results emphasize the importance of considering intraspecific competition and interspecific interactions such as predation when analyzing reproductive and actuarial senescence.
Journal Article
An experimental analysis of the heritability of variation in glucocorticoid concentrations in a wild avian population
Glucocorticoid hormones (CORT) are predicted to promote adaptation to variable environments, yet little is known about the potential for CORT secretion patterns to respond to selection in free-living populations. We assessed the heritable variation underlying differences in hormonal phenotypes using a cross-foster experimental design with nestling North American barn swallows (Hirundo rustica erythrogaster). Using a bivariate animal model, we partitioned variance in baseline and stress-induced CORT concentrations into their additive genetic and rearing environment components and estimated their genetic correlation. Both baseline and stress-induced CORT were heritable with heritability of 0.152 and 0.343, respectively. We found that the variation in baseline CORT was best explained by rearing environment, whereas the variation in stress-induced CORT was contributed to by a combination of genetic and environmental factors. Further, we did not detect a genetic correlation between these two hormonal traits. Although rearing environment appears to play an important role in the secretion of both types of CORT, our results suggest that stress-induced CORT levels are underlain by greater additive genetic variance compared with baseline CORT levels. Accordingly, we infer that the glucocorticoid response to stress has a greater potential for evolutionary change in response to selection compared with baseline glucocorticoid secretion patterns.
Journal Article
Rainy springs linked to poor nestling growth in a declining avian aerial insectivore ( Tachycineta bicolor )
As species shift their ranges and phenology to cope with climate change, many are left without a ready supply of their preferred food source during critical life stages. Food shortages are often assumed to be driven by reduced total food abundance, but here we propose that climate change may cause short-term food shortages for foraging specialists without affecting overall food availability. We frame this hypothesis around the special case of birds that forage on flying insects for whom effects mediated by their shared food resource have been proposed to cause avian aerial insectivores' decline worldwide. Flying insects are inactive during cold, wet or windy conditions, effectively reducing food availability to zero even if insect abundance remains otherwise unchanged. Using long-term monitoring data from a declining population of tree swallows ( Tachycineta bicolor ), we show that nestlings’ body mass declined substantially from 1977 to 2017. In 2017, nestlings had lower body mass if it rained during the preceding 3 days, though females increased provisioning rates, potentially in an attempt to compensate. Adult body mass, particularly that of the males, has also declined over the long-term study. Mean rainfall during the nestling period has increased by 9.3 ± 0.3 mm decade −1 , potentially explaining declining nestling body mass and population declines. Therefore, we suggest that reduced food availability, distinct from food abundance, may be an important and previously overlooked consequence of climate change, which could be affecting populations of species that specialize on foraging on flying insects.
Journal Article
Radioactive contamination and climate warming affect physiological performance of Chornobyl barn swallows
Global warming and degradation of natural habitats are the two main factors causing ecophysiological stress on individuals and risk for biodiversity. Hyperthermia is a common response to stress in homeothermic animals, in particular to heat, pathogens and environmental contamination. Resilience of biological systems to global warming may be deteriorated in polluted habitats. Here we investigated how body temperature of a wild bird, the barn swallow ( Hirundo rustica ), responded to global warming while simultaneously exposed to radioactive contamination from the Chernobyl accident. Our results showed that both high air temperatures (t = 15.55, df = 335, p < 0.0001) and elevated environmental radioactive contamination (t = 5.18, df = 8.09, p = 0.0008) increased internal body temperature of individuals. The additive effect suggests that birds might suffer hyperthermia in locally contaminated habitat (1.47% body temperature increase) while simultaneously exposed to globally rising temperatures (1.95% body temperature increase), potentially reducing the fitness of individual and the maintenance of breeding colonies. The cumulative and interactive negative effects of multiple stressors, such as those emerging from increasing habitat degradation and climate change, will likely contribute to biodiversity losses globally.
Journal Article
Diurnal and crepuscular activity during fall migration for four species of aerial foragers/Activite diurne et crepusculaire pendant la migration autoninale pour quatre especes d'insectivores aeriens
Most migratory birds, particularly passerines or songbirds, migrate at night. However, diurnal migration has many benefits, including the ability to use a fly-and-forage migration strategy that allows an individual to refuel while migrating. Despite these benefits, very little research has been undertaken on diurnal migrants, including aerial foragers, who can refuel on the wing. In this study, we use the Motus Wildlife Tracking System to examine the timing of Bank Swallow (Riparia riparia), Barn Swallow (Hirundo rustica). Cliff Swallow (Petrochelidon pyrrhonota), and Tree Swallow (Tachycineta bicolor) movements during fall migration. Using these data, we confirm the \"common knowledge\" that these species of aerial foragers are diurnal migrants. During fall migration, 88.2% detections across all species were during the day, and the remaining detections were during civil twilight (range of sun elevation angles: -5.4[degrees] to 0[degrees]). Most of the detections during the day were consistent with migratory movement, and most detections during civil twilight were consistent with movements to and from communal roosts. Collectively, these results indicate that during fall migration, these 4 swallow species migrate during the day and, like other aerial foragers, may use a fly-and-forage migration strategy. Received 1 May 2019. Accepted 13 November 2019.
Journal Article
Multiple Sexual Signals and Behavioral Reproductive Isolation in a Diverging Population
Sexual trait divergence has been shown to play a role in the evolution of reproductive isolation. While variation in multiple sexual signals is common among closely related species, little is known about the role of these different axes of phenotype variation with respect to the evolution of behavioral reproductive isolation. Here we study a unique population of barn swallows (Hirundo rustica transitiva) that can be distinguished phenotypically from its neighboring populations only on the basis of two features of male plumage: exaggerated expression of both long tail streamers and dark ventral coloration. Using phenotype manipulation experiments, we conducted a paternity study to examine whether both traits are sexually selected. Our results show that an exaggerated form of the local male phenotype (with both tail elongation and color darkening) is favored by local females, whereas males whose phenotypes were manipulated to look like males of neighboring subspecies suffered paternity losses from their social mates. These results confirm the multiple signaling role of the unique tail and color combination in our diverging population and suggest a novel possibility according to which multiple sexual signals may also be used to discriminate among males from nearby populations when prezygotic reproductive isolation is adaptive.
Journal Article
Utilizing Modified Barium Swallow Impairment Profile (MBSImP) to Characterize Swallowing Function Following Total Laryngectomy
Objective We aim to determine the frequency of altered swallowing physiology for ratable components of the 17‐component grading system, the Modified Barium Swallow Impairment Profile (MBSImp), in its current validated state for a cohort of patients post total laryngectomy (TL). Study Design Retrospective study. Setting Otolaryngology Head & Neck Surgery, The George Washington University Hospital and George Washington University Medical Faculty Associates. Methods All participants received a VFSS as part of standard care, which was scored post hoc using the MBSImP protocol and scoring metric by two blinded speech‐language pathologists. Results Due to anatomical changes post‐TL, Components 6, 8, 9, 10, and 11 of the MBSImP were not rated. Efficiency concerns were most prevalent with functional deficits noted for: pharyngeal stripping wave, pharyngoesophageal segment opening, tongue base retraction, pharyngeal residue, and esophageal clearance. Conclusions Our work aims to provide further insight into the swallowing characteristics of TL as measured using the MBSImP. A high frequency of biomechanical impairment was identified in this cohort of patients. Although the MBSImP is a validated tool its application to the reconstructed anatomy following TL is not precise and should be regarded with caution in clinical settings. Further work is needed to modify definitions of the MBSImP components and inclusion of additional features that can more accurately describe post‐TL dysphagia.
Journal Article