Lifetime fitness benefits of breeding site fidelity and low costs of inbreeding permit inbreeding tolerance in an avian cooperative breeder.

Inbreeding, or breeding with close relatives, often decreases individual fitness, but mate choice in many species can increase inbreeding risk. Inbreeding is more likely in species with limited dispersal, such as cooperative breeders where non-parental individuals-often offspring from previous broods-provide parental care and frequently breed close to home. We leverage 32 years of data from a population of Florida Scrub-Jays ( ), an avian cooperative breeder, to investigate whether mate choice, and its lifetime fitness outcomes, affects inbreeding tolerance.

Allele frequency dynamics under sex-biased demography and sex-specific inheritance in a pedigreed jay population.

Sex-biased demography, including sex-biased survival or migration, can alter allele frequency changes across the genome. In particular, we can expect different patterns of genetic variation on autosomes and sex chromosomes due to sex-specific differences in life histories, as well as differences in effective population size, transmission modes, and the strength and mode of selection. Here, we demonstrate the role that sex differences in life history played in shaping short-term evolutionary dynamics across the genome.

Impacts of increasing isolation and environmental variation on Florida Scrub-Jay demography.

Isolation caused by anthropogenic habitat fragmentation can destabilize populations. Populations relying on the inflow of immigrants can face reduced fitness due to inbreeding depression as fewer new individuals arrive. Empirical studies of the demographic consequences of isolation are critical to understand how populations persist through changing conditions.

Visual Monitoring Strategies of Sentinels in a Cooperative Breeder.

Vigilance is important for early detection of threats. Previous studies have focused on the allocation of time to vigilance but neglected how animals monitor their surroundings during vigilance. Where animals look and how long each look lasts can affect the quality of visual monitoring and thus the ability to detect threats during vigilance.

Dynamics of reduced genetic diversity in increasingly fragmented populations of Florida scrub jays,.

Understanding the genomic consequences of population decline is important for predicting species' vulnerability to intensifying global change. Empirical information about genomic changes in populations in the early stages of decline, especially for those still experiencing immigration, remains scarce. We used 7834 autosomal SNPs and demographic data for 288 Florida scrub jays (; FSJ) sampled in 2000 and 2008 to compare levels of genetic diversity, inbreeding, relatedness, and lengths of runs of homozygosity (ROH) between two subpopulations within dispersal distance of one another but have experienced contrasting demographic trajectories.

Staging to join non-kin groups in a classical cooperative breeder, the Florida scrub-jay.

Why unrelated members form groups in animal societies remains a pertinent topic in evolutionary biology because benefits for group members often are not obvious. We studied subordinates that disperse to join unrelated social groups in the Florida scrub-jay Aphelocoma coerulescens, a cooperative breeding species mainly composed of kin-based groups. We evaluated potential adaptive benefits of dispersing to become an unrelated helper (staging) versus remaining home and dispersing only to pair and breed (direct dispersal) to understand why non-kin-based groups form.

Fire history and weather interact to determine extent and synchrony of mast-seeding in rhizomatous scrub oaks of Florida.

In disturbance-prone ecosystems, fitness consequences of plant reproductive strategies are often determined by the relative timing of seed production and disturbance events, but the role of disturbances as proximate drivers of seed production has been overlooked. We use long-term data on seed production in , and , rhizomatous oaks found in south central Florida's oak scrub, to investigate the role of fire history and its interaction with weather in shaping acorn production and its synchrony Acorn production increased with the time since last fire, combined with additive or interactive effects of spring precipitation (+) or drought (-). Furthermore, multiple matrix regression models revealed that ramet pairs with shared fire history were more synchronous in seed production than ones that burned in different years.

Life history stage explains behavior in a social network before and during the early breeding season in a cooperatively breeding bird.

In species with stage-structured populations selection pressures may vary between different life history stages and result in stage-specific behaviors. We use life history stage to explain variation in the pre and early breeding season social behavior of a cooperatively breeding bird, the Florida scrub-jay () using social network analysis. Life history stage explains much of the variation we observed in social network position.

Allele frequency dynamics in a pedigreed natural population.

A central goal of population genetics is to understand how genetic drift, natural selection, and gene flow shape allele frequencies through time. However, the actual processes underlying these changes-variation in individual survival, reproductive success, and movement-are often difficult to quantify. Fully understanding these processes requires the population pedigree, the set of relationships among all individuals in the population through time.

Mass fluctuation in breeding females, males, and helpers of the Florida scrub-jay .

Much evidence suggests that birds actively regulate their body mass reserves relative to their energy needs. Energy requirements during reproduction may differ in relation to sex-specific behavioural roles or, in the case of cooperative breeders, breeders relative to helpers. We measured body mass of free-living Florida scrub-jays throughout the nesting season by training them to land on an electronic balance.

Deconstructing isolation-by-distance: The genomic consequences of limited dispersal.

Geographically limited dispersal can shape genetic population structure and result in a correlation between genetic and geographic distance, commonly called isolation-by-distance. Despite the prevalence of isolation-by-distance in nature, to date few studies have empirically demonstrated the processes that generate this pattern, largely because few populations have direct measures of individual dispersal and pedigree information. Intensive, long-term demographic studies and exhaustive genomic surveys in the Florida Scrub-Jay (Aphelocoma coerulescens) provide an excellent opportunity to investigate the influence of dispersal on genetic structure.

Genomic Consequences of Population Decline in the Endangered Florida Scrub-Jay.

Understanding the population genetic consequences of declining population size is important for conserving the many species worldwide facing severe decline [1]. Thorough empirical studies on the impacts of population reduction at a genome-wide scale in the wild are scarce because they demand huge field and laboratory investments [1, 2]. Previous studies have demonstrated the importance of gene flow in introducing genetic variation to small populations [3], but few have documented both genetic and fitness consequences of decreased immigration through time in a natural population [4-6].

Selection and inheritance of sexually dimorphic juvenile plumage coloration.

Sexually dimorphic plumage coloration is widespread in birds and is generally thought to be a result of sexual selection for more ornamented males. Although many studies find an association between coloration and fitness related traits, few of these simultaneously examine selection and inheritance. Theory predicts that sex-linked genetic variation can facilitate the evolution of dimorphism, and some empirical work supports this, but we still know very little about the extent of sex linkage of sexually dimorphic traits.

Hatching asynchrony that maintains egg viability also reduces brood reduction in a subtropical bird.

In birds, hatching failure is pervasive and incurs an energetic and reproductive cost to breeding individuals. The egg viability hypothesis posits that exposure to warm temperatures prior to incubation decreases viability of early laid eggs and predicts that females in warm environments minimize hatching failure by beginning incubation earlier in the laying period, laying smaller clutches, or both. However, beginning incubation prior to clutch completion may incur a cost by increasing hatching asynchrony and possibly brood reduction.

The effects of low levels of light at night upon the endocrine physiology of western scrub-jays (Aphelocoma californica).

Florida scrub-jays (Aphelocoma coerulescens) in the suburbs breed earlier than jays in native habitat. Amongst the possible factors that influence this advance (e.g.

Mind the gap: genetic distance increases with habitat gap size in Florida scrub jays.

Habitat gap size has been negatively linked to movement probability in several species occupying fragmented landscapes. How these effects on movement behaviour in turn affect the genetic structure of fragmented populations at local scales is less well known. We tested, and confirmed, the hypothesis that genetic differentiation among adjacent populations of Florida scrub jays--an endangered bird species with poor dispersal abilities and a high degree of habitat specialization--increases with the width of habitat gaps separating them.

Circulating carotenoid concentrations are positively correlated with later clutch initiation in Florida Scrub-Jays (Aphelocoma coerulescens).

Antioxidants play key roles in preventing free radical damage to various molecules, cells, and tissues, but it is not well understood how variation in antioxidant levels may relate to the reproductive success or health of wild animals. We explored the relationship between circulating antioxidant concentrations and both body condition and timing of reproduction in male and female Florida Scrub-Jays (Aphelocoma coerulescens), a cooperatively breeding passerine bird. We examined whether levels of uric acid, vitamin E, and carotenoids (all potentially important antioxidants) were linked to body condition and timing of reproduction, two measures that are directly related to reproductive success.

Effects of habitat fragmentation on effective dispersal of Florida scrub-jays.

Studies comparing dispersal in fragmented versus unfragmented landscapes show that habitat fragmentation alters the dispersal behavior of many species. We used two complementary approaches to explore Florida Scrub-Jay (Aphelocoma coerulescens) dispersal in relation to landscape fragmentation. First, we compared dispersal distances of color-marked individuals in intensively monitored continuous and fragmented landscapes.

Temporal predictability in food availability: effects upon the reproductive axis in Scrub-Jays.

Florida Scrub-Jays (Aphelocoma coerulescens) in a suburban environment with year-round access to multiple sources of abundant, human-source foods consistently breed earlier each year and have lower baseline levels of circulating corticosterone (CORT) than jays in a nearby wildland setting. These findings suggest that food supplies influence CORT levels, which in turn may partially determine the timing of reproduction. However, wildland birds with access to high-quality supplemental foods did not advance breeding or lower CORT levels to the degree observed in the suburbs.

Baseline and acute levels of corticosterone in Florida Scrub-Jays (Aphelocoma coerulescens): effects of food supplementation, suburban habitat, and year.

Recent work has shown that Florida Scrub-Jays (Aphelocoma coerulescens) living in suburban habitats, as well as birds that reside in a natural habitat (hereafter referred to as wildland birds) provided supplemental food during the pre-breeding period, have lower baseline corticosterone (CORT) levels than nonsupplemented wildland birds, suggesting that predictable and abundant foods can lower stress levels. Here, we investigate whether the acute CORT response to capture stress reflects our earlier findings. During the pre-breeding seasons in 2004 and 2005 we captured over 200 Florida Scrub-Jays and collected four blood samples from each bird over a 30 min time period.

Corticosterone administration does not affect timing of breeding in Florida scrub-jays (Aphelocoma coerulescens).

Providing supplemental food to Florida scrub-jays (Aphelocoma coerulescens) causes a reliable advance in clutch initiation of 1 to 2 weeks. In some years, supplemental food appeared to not only advance laying date but also decrease baseline concentrations of corticosterone (CORT) relative to controls. The coincidence of low CORT levels and early breeding led us to hypothesize that CORT serves to communicate information about environmental conditions to the hypothalamic-pituitary-gonadal (HPG) axis, which ultimately influences the timing of breeding.

Food supplementation and possible mechanisms underlying early breeding in the Florida Scrub-Jay (Aphelocoma coerulescens).

Food supplementation studies demonstrate the importance of resources in the timing of reproduction. Studies of Florida Scrub-Jays (Aphelocoma coerulescens) found that supplemented jays bred earlier than unsupplemented jays and that protein may play a critical role. In this study, free-living scrub-jays were provided with supplemental diets high in fat and protein (HFHP) or high in fat and low in protein (HFLP).

Metal and metalloid concentrations in the eggs of threatened Florida scrub-jays in suburban habitat from south-central Florida.

Monitoring and assessing changes in contaminants in urban and suburban environments is essential to assessing ecosystem well-being in human-influenced landscapes. We analyzed metal and metalloid levels in the eggs of the threatened Florida scrub-jay (Aphelocoma coerulescens), an extremely sedentary and modestly long-lived passerine bird that is federally threatened and endemic only in Florida. Eggs that failed to hatch were collected in a suburban environment to compare with the long-term study of this species at the Archbold Biological Station, located 8 km south in a more rural part of south-central Florida.