No Evidence that Songbirds Use Odour Cues to Avoid Malaria-infected Conspecifics

Many animals have evolved mechanisms to detect and avoid parasitized conspecifics, primarily through odour cues, but whether birds are capable of odour-mediated parasite avoidance is unknown. Recently, we showed that exposing song sparrows (Melospiza melodia) to avian malaria parasites (Plasmodium sp.) alters the chemical composition of their preen oil, which is the major source of body odour in birds. Here, we presented song sparrows with preen oil from uninfected (sham-inoculated) and malaria-infected conspecifics, predicting that birds would spend more time with odour cues from uninfected than infected birds. Birds without detectable malarial infections spent about 50% more time with preen oil from uninfected than infected conspecifics, and females spent nearly twice as much time with preen oil from uninfected than infected conspecifics. However, neither difference was statistically significant. Song sparrows may be unable to detect odour cues of infection, but further experiments are needed to confirm or refute this

Developmental stress, condition, and birdsong: a case study in song sparrows.

Sexual-selection theory posits that ornaments and displays can reflect a signaler\u27s condition, which in turn is affected both by recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits exhibit developmental phenotypic plasticity in response to stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. Here, we review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of birds from a long-term study of a population of song sparrows (Melospiza melodia). Field studies of free-living birds indicate that the complexity of a male\u27s songs, a permanent trait, reflects the size of a song-control region of his brain (HVC), and is correlated with body size and several parameters of immunity, specifically investment in protective proteins. However, the performance of a male\u27s songs, a dynamic trait, is not correlated to immune investment. Complexity of song is correlated with the glucocorticoid stress-response, and in some years response to stress predicts overwinter survival. Experimental manipulations have revealed that stressors in early life impair development of HVC, but that HVC recovers in size by adulthood. These manipulations result in impaired song-complexity and song-learning, but not song-performance. Experimental developmental stressors also affect growth, endocrine physiology, metabolism, and immune-function, often in a sex-specific manner. Combined, these studies suggest that song-complexity provides reliable information about early developmental experience, and about other traits that have critical developmental periods. Birdsong thus provides a multi-faceted sexually selected trait that may be an indicator both of developmental and recent conditions

The role of employee motives in determining the type and consequences of citizenship behavior: The introduction of the OCB-Intentionality Scale

Several decades have passed since organizational citizenship behavior (OCB) began to permeate the organizational sciences. Only recently, however, have scholars begun to critically analyze the motives that drive OCB. The present effort first draws from the extant literature to introduce a typology of nine motives believed to underlie citizenship behavior. Next, two studies report on the development and initial validation of the OCB-Intentionality Scale (OCB-IS), a questionnaire designed to capture the nine motives elucidated in the typology. Study 1 outlines the scale construction and refinement process and establishes construct-related validation evidence through the formation of a nomological network. Study 2 provides further evidence of construct validity and examines the predictive utility of the OCB-IS. Results indicate that each of the nine motives relate in unique ways to individual difference and situational correlates, and that they differentially predict OCB dimensions and employee-relevant OCB outcomes. Implications and future research directions are discussed

Long-term winter-site fidelity in Song Sparrows (Melospiza melodia)

In migratory animals, the degree to which individuals return to the same wintering sites across multiple years can affect fitness and population dynamics, and thus has important implications for conservation. Despite this, long-term evaluations of wintering-site fidelity are rare for migratory birds: many populations are intensively studied on their breeding grounds but tracking the migratory movements of small birds once they leave the breeding grounds is challenging. To evaluate patterns of overwintering location and fidelity, we collected winter-grown claw tissue from 301 Song Sparrows (Melospiza melodia; 449 samples) captured in spring at their breeding grounds over six consecutive years and assessed stable hydrogen isotope (δ2Hc) values to determine within-individual repeatability and between-year variation in wintering latitudes. We also retrieved useable data from eight geolocators over two consecutive winters. Geolocator-derived wintering positions correlated with origins based on δ2Hc values. Consistent with previous findings, male δ2Hcvalues reflected more northerly wintering areas than those of females, indicating shorter latitudinal migration distances for males, but the magnitude of the sex difference varied across years. The distribution of wintering latitudes was generally consistent among years, except for the 2015 – 2016 winter that had unusually negative δ2Hc values. Values of δ2Hc were repeatable for males but not for females, suggesting that winter-site fidelity could differ between sexes. The data presented here emphasize the importance of tracking migratory populations across multiple years to uncover factors affecting population dynamics

Testosterone, Migration Distance, and Migratory Timing in Song Sparrows Melospiza melodia

In seasonally migratory animals, migration distance often varies substantially within populations such that individuals breeding at the same site may overwinter different distances from the breeding grounds. Shorter migration may allow earlier return to the breeding grounds, which may be particularly advantageous to males competing to acquire a breeding territory. However, little is known about potential mechanisms that may mediate migration distance. We investigated naturally-occurring variation in androgen levels at the time of arrival to the breeding site and its relationship to overwintering latitude in male and female song sparrows (Melospiza melodia). We used stable isotope analysis of hydrogen (δ2H) in winter-grown claw tissue to infer relative overwintering latitude (migration distance), combined with 14 years of capture records from a long-term study population to infer the arrival timing of males versus females. Relative to females, males had higher circulating androgen levels, migrated shorter distances, and were more likely to be caught early in the breeding season. Males that migrate short distances may benefit from early arrival at the breeding grounds, allowing them to establish a breeding territory. Even after controlling for sex and date, androgen levels were highest in individuals that migrated shorter distances. Our findings indicate that androgens and migration distance are correlated traits within and between sexes that may reflect individual variation within an integrated phenotype in which testosterone has correlated effects on behavioral traits such as migration

Immune Profiles Vary Seasonally, But Are Not Significantly Related To Migration Distance Or Natal Dispersal, In A Migratory Songbird

A central tenet of ecoimmunology is that an organism’s environment shapes its optimal investment in immunity. For example, the benefits of acquired (relatively pathogen-specific) versus innate (non-specific) immune defences are thought to vary with the risk of encountering familiar versus unfamiliar pathogens. Because pathogen communities vary geographically, individuals that travel farther during seasonal migration or natal dispersal are predicted to have higher exposure to novel pathogens, and lower exposure to familiar pathogens, potentially favoring investment in innate immunity. During the breeding season, migratory animals’ exposure to familiar pathogens should increase, potentially favoring investment in acquired immunity. We hypothesized that song sparrows Melospiza melodia adjust their constitutive immune profiles in response to risk of encountering novel versus familiar pathogens. We predicted that individuals migrating longer distances (inferred from stable hydrogen isotope analysis of claws) and less philopatric individuals (inferred from microsatellite assignment testing) would rely more heavily on acquired than innate defences. We also predicted that reliance on acquired defences would increase throughout the early breeding season. Consistent with trade-offs between acquired and innate defences, levels of immunoglobulin Y (acquired) varied negatively with macrophage phagocytosis activity (innate). Levels of acquired relative to innate immunity did not vary significantly with migration distance or philopatry, but increased throughout the early breeding season. Macrophage phagocytosis was not significantly repeatable between years. Song sparrows appear to shift from innate defences immediately after migration, to acquired defences with increasing time at the breeding grounds. These patterns highlight the plasticity of constitutive immune defences in migratory animals

Book Reviews

Reviews of the following books: The Massachusetts Historical Society: A Bicentennial History, 1791-1991 by Louis Leonard Tucker; Interpreting Early American History Essays by Jack P. Greene; Molly Spotted Elk: A Penobscot in Paris by Bunny McBride; The Artist\u27s Mount Desert: American Painters on the Maine Coast by John Wilmerding; Politics of Conscience: A Biography of Margaret Chase Smith by Patricia Ward Wallace; Maine, A Peopled Landscape: Salt Documentary Photography, 1978 to 1995 edited by Hugh French, with essays by C. Stewart Doty, James C. Curtis and R. Todd Hoffman; Always Rachel: The Letters of Rachel Carson and Dorothy Freeman, 1952-1964 by Martha Free.man; Sarah Orne Jewett: Her World and Her Work by Paula Blanchar

Access and Health System Impact of an Early Intervention Treatment Program for Emerging Adults with Mood and Anxiety Disorders

Objectives: Early intervention programs are effective for improving outcomes in first-episode psychosis; however, less is known about their effectiveness for mood and anxiety disorders. We sought to evaluate the impact of an early intervention program for emerging adults with mood and anxiety disorders in the larger health system context, relative to standard care. Methods: Using health administrative data, we constructed a retrospective cohort of cases of mood and anxiety disorders among emerging adults aged 16 to 25 years in the catchment of the First Episode Mood and Anxiety Program (FEMAP) in London, Ontario, between 2009 and 2014. This cohort was linked to primary data from FEMAP to identify service users. We used proportional hazards models to compare indicators of service use between FEMAP users and a propensity score–matched group of nonusers receiving care elsewhere in the health system. Results: FEMAP users (n = 490) had more rapid access to a psychiatrist relative to nonusers (hazard ratio [HR], 2.82; 95% confidence interval, 2.45 to 3.26; median time, 16 vs. 71 days). In the year following admission, FEMAP users also had lower rates of emergency department use for mental health reasons (HR, 0.73; 95% CI, 0.53 to 0.99). We did not observe differences in psychiatric hospitalization rates. Conclusions: An early intervention model of care for mood and anxiety disorders is associated with better access to psychiatric care and lower use of the emergency department. Our findings suggest that early intervention services for mood and anxiety disorders may be beneficial from a health systems perspective, and further research on the effectiveness of this model of care is warranted

Seasonal Migration Distance Varies With Natal Dispersal and Predicts Parasitic Infection in Song Sparrows

Seasonal migration and natal dispersal represent the major large-scale movements in the lives of animals. Individuals that are relatively prone to movement and exploration might thus be more likely to disperse and also to migrate farther. Such movement might be either negatively associated with parasitic infection (if infection prevents hosts from successful long-distance migration) or positively associated (e.g. if longer-distance migrants encounter more abundant or more diverse parasites). We examined whether natal dispersal tendency predicts seasonal migration distance in song sparrows (Melospiza melodia) and whether migration distance predicts infection with bloodborne parasites upon arrival at the breeding grounds. Migration distance, inferred from stable hydrogen isotope analysis (δ2H) of winter-grown tissue, was repeatable (repeatability = 0.41) over years. Birds that were more likely to have immigrated from outside the breeding grounds, as inferred from genetic assignment tests, also overwintered farther south, as inferred from stable isotope analysis. The finding that individuals more prone to movement in the context of natal dispersal also tended to travel farther, on average, in the context of seasonal migration suggests consistent individual variation in large-scale movements across these two contexts. Although statistically significant, this effect was modest in scope and subtle relative to sex differences in inferred migration distance. Among after-second-year individuals, but not yearlings, longer-distance migrants were more likely, on average, to be infected with bloodborne parasites. Individual variation in propensity to long-distance movement may interact with age-related variation in exposure or susceptibility to parasites, to shape the role of animal migration in transporting infectious disease