Preen oil composition of Pied Flycatchers is similar between partners but differs between sexes and breeding stages

Preen oil, the secretion of the uropygial gland, may be an important source of body odour in birds. By characterizing the chemical composition of preen oil, we can describe the olfactory phenotypes of birds and investigate whether odours could have a function in sexual signalling or other chemical communication. Here we analysed the preen oil of a wild passerine, the European Pied Flycatcher Ficedula hypoleuca, to find out whether it holds socially relevant information. We sampled both the female and male of breeding pairs during nestling rearing to test for sex differences and within-pair similarity. We additionally sampled the females during incubation to test for changes across breeding stages and for individual repeatability of chemical profiles. Pair mates had similar chemical profiles in comparison with other breeding adults. Furthermore, we found evidence for sex differences and for changes across breeding stages. Notably, the preen oil of females was more diverse and more volatile than that of males, and the preen oil secreted by females during incubation was more volatile than that secreted during nestling rearing. However, we found no evidence for individual repeatability of chemical profiles across breeding stages in females. Our results point towards a function of preen oil in sexual signalling, although other functions should not be excluded. Our study is a first step towards understanding the role of odours in the social life of an important avian model species used in the study of mate choice and sexual selection.     

Experimental study of the effect of preen oil against feather bacteria in passerine birds

Avian plumage harbors various pathogens such as feather-degrading bacteria, which have the potential to reduce host fitness. A growing body of evidence suggests that the secretion of the uropygial gland of birds—preen oil—acts as one of the first lines of defence against harmful bacteria. However, previous studies on the antimicrobial impact of preen oil have yielded controversial results. The impact of preen oil on bacterial densities of feathers was experimentally investigated in two passerine species: great tits Parus major and pied flycatchers Ficedula hypoleuca. More specifically, we tested whether the antibacterial effect of the preen oil secreted by the same individual differs from that of the preen oil originating from the gland of other species. In the laboratory, ventral feathers were treated with preen oil from (1) an individual’s own gland, (2) from the gland of another passerine species, or (3) from the gland of a phylogenetically distant bird species. We detected a significant antibacterial effect of preen oil on bacteria that were attached to feathers, though the effect did not depend on whether the oil originated from the individual’s own gland or from the gland of another bird species. However, treatment with preen oil suppressed the density of bacteria more in the pied flycatcher than in the great tit. This is the first study providing experimental evidence that preen oil represents an important antimicrobial mechanism against those plumage bacteria that are attached to feathers.     

Preen oil chemical composition encodes individuality,seasonal variation and kinship in black kites Milvus migrans

Evidence that bird odour can encode social information that can be used in chemical communication is growing, but is restricted to a few taxonomic groups. Among birds, diurnal raptors (i.e. birds from the Accipitriformes and Falconiformes order) have always been considered as mainly relying on their visual abilities. Although they seem to have a functional sense of smell, whether their odour can convey social information has yet to be determined. Combining gas‐chromatography‐mass‐spectrometry (GCMS) and microsatellite data, we tested whether chemical compounds from preen gland secretions can encode sex, age, individuality, seasonal differences and genetic relatedness in the gregarious accipitriform black kite Milvus migrans. While no differences in preen oil composition were found between age classes, an individual signature was detected. While a seasonal variation was found in both sexes, compounds differ between sexes in the non‐breeding season. Finally, a significant correlation between chemical proximity and genetic proximity was detected in male–male dyads and male–female dyads but not in female–female dyads. Our study provides the first evidence in raptors that preen secretion can convey information that may potentially be used in individual recognition, reproductive synchronization and inbreeding avoidance, and suggests that raptors may rely upon their olfactory abilities more than previously thought. This study opens promising avenues for further studies in raptor chemical communication.     

Chemical labels differ between two closely related shearwater taxa

Chemical signals may be the basis of interspecific recognition and speciation in many animals. To test whether a chemical label allowing recognition between closely related species exists in seabirds, we investigated two closely related taxa breeding sympatrically at some localities: Cory's and Scopoli's shearwaters. Procellariiform seabirds are ideal for this study because they have a well‐developed olfactory system and unequalled associated capabilities among birds. We analysed and compared the relative volatile compounds composition of the uropygial gland secretions of Cory's and Scopoli's shearwaters. As the volatile components from uropygial secretions might also provide some critical eco‐chemical information about population origin and sex, we also examined variations in the volatile compounds between populations and sexes in Cory's shearwater. The chemical data were obtained using gas chromatography–mass spectrometry techniques looking for the presence of these three particular labels: species, population and gender. We found diagnostic differences in uropygial secretions between the two species of shearwaters and smaller but significant variation between populations of Cory's shearwater in the Atlantic. No significant differences were observed between males and females. Individuals might thus use the chemical variation between species to recognize and mate with conspecifics, especially at localities where both species breed sympatrically. Geographical variation in chemical composition of uropygial secretions suggests that selective forces might vary according to locality, and might represent a key in the species recognition. Further behavioural bioassays are needed to determine whether or not these species labels are signals allowing reproductive isolation between these two taxa. Finally, one of the aims of our study was to test easier methods than freezing for storing uropygial gland secretions in the field. We describe here a new possibility for the storage of uropygial secretion samples at ambient temperature in the field, providing an alternative, simple protocol for the sampling of avian chemosignals.     

Behavioral responses of nesting female dark‐eyed juncos Junco hyemalis to hetero‐ and conspecific passerine preen oils

Several studies have suggested a greater role for olfactory cues in avian social interactions than previously recognized, but few have explicitly investigated the effect of odor on parental behavior. We present results from a preliminary study in which we applied hetero‐ and conspecific preen gland secretions, which are known to contain volatile compounds, to the nests and eggs of incubating female dark‐eyed juncos Junco hyemalis. The responses to these two conditions were compared to the responses of females whose nests were treated with their own preen oil as a control condition, and to females whose nests were treated with the vehicle only. We found that females significantly reduced incubation bout length, a form of parental care, in response to alien secretions, more so if they came from a heterospecific than a conspecific. Females did not reduce incubation bout length in response to their own preen oil or to a vehicle‐only control. These results suggest that odors in the nest may influence avian parental care. However, the behavioral change was only temporary and had no effect on later hatching success. In our study population, brood parasitism by brown‐headed cowbirds is common, but resulting nest abandonment is rare; juncos are frequently able to successfully breed even with cowbird nestlings in their nests. Thus, we suggest that more extreme behavioral responses to alien odor, such as nest abandonment or egg ejection, may not be adaptive and should not be expected.     

Female-biased dispersal, low female recruitment, unpaired males, and the extinction of small and isolated bird populations

Small and isolated populations are usually assumed to be at a high risk of extinction due to environmental or demographic stochasticity, genetic problems, or too little immigration. In birds, natal dispersal is usually female-biased, but the consequences of such a pattern on vulnerability to extinction of isolated populations has not received much attention before. In this paper I derive predictions as to how female-biased natal dispersal may differentially affect the extinction risk of populations and species with contrasting distributions, migratory behaviours, life histories and mating systems. Female-biased dispersal will lead to male-biased sex ratios in small, isolated or fragmented populations, in particular because recent research has shown that females often have a limited ability to search for mates and may therefore effectively be lost from the breeding population if they disperse into areas empty of conspecifics. I reviewed published studies on birds and found that a high proportion of unpaired males is common in isolated populations or populations in small habitat fragments. Dispersal of females may therefore increase the vulnerability to extinction of small or isolated populations, or populations at the periphery of a species' distribution range. I also predict that vulnerability to extinction should be greater for migratory than for resident species and greater for short-lived than for long-lived species because of differences in the time available for females to locate unpaired males. Further, extinction risk may also be greater for birds than for mammals due to differences in which sex disperses and patterns of parental care. Finally, mating system will also affect vulnerability to extinction when natal dispersal leads to biased sex ratios. I review available evidence for these predictions (e.g. songbird declines in North America) and discuss implications for conservation.     

Olfactory discrimination of anal sac secretions in the domestic cat and the chemical profiles of the volatile compounds

Scent emitted from anal sac secretions provides important signals for most Carnivora. Their secretions emit a variety of volatile compounds, some of which function as chemical signals with information about the scent owners. The domestic cat has a pair of anal sac glands to secrete a pungent liquid. Their anal sac secretions may give information about sex, reproductive state, and recognition of individuals. However, little is known about the volatile compounds emitted from anal sac secretions and their biological functions in cats. In this study, we examined the volatile chemical profiles of anal sac secretions in cats and their olfactory ability to discriminate intraspecific anal sac secretions. Analysis with gas chromatography–mass spectrometry showed that the major volatile compounds were short-chain free fatty acids, whose contents varied among individuals, as well as other carnivores. There was no sex difference in the volatile profiles. In temporal analyses of individual anal sac secretions performed 2 months apart, the profiles were highly conserved within individuals. Habituation–dishabituation tests showed that cats can distinguish individual differences in the odor of anal sac secretions. These results suggest that cats utilize short-chain free fatty acids emitted from anal sac secretions to obtain scent information for individual recognition rather than species or sex recognition.     

Chemical Variation in a Dominant Tree Species: Population Divergence,Selection and Genetic Stability across Environments

Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E). We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs) in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h²op = 0.24) to high (e.g., macrocarpal G h²op = 0.48) narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal) and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes.     

Genetic divergence and phenotypic plasticity contribute to variation in cuticular hydrocarbons in the seaweed fly Coelopa frigida

Cuticular hydrocarbons (CHCs) form the boundary between insects and their environments and often act as essential cues for species, mate, and kin recognition. This complex polygenic trait can be highly variable both among and within species, but the causes of this variation, especially the genetic basis, are largely unknown. In this study, we investigated phenotypic and genetic variation of CHCs in the seaweed fly, Coelopa frigida, and found that composition was affected by both genetic (sex and population) and environmental (larval diet) factors. We subsequently conducted behavioral trials that show CHCs are likely used as a sexual signal. We identified general shifts in CHC chemistry as well as individual compounds and found that the methylated compounds, mean chain length, proportion of alkenes, and normalized total CHCs differed between sexes and populations. We combined these data with whole genome resequencing data to examine the genetic underpinnings of these differences. We identified 11 genes related to CHC synthesis and found population‐level outlier SNPs in 5 that are concordant with phenotypic differences. Together these results reveal that the CHC composition of C. frigida is dynamic, strongly affected by the larval environment, and likely under natural and sexual selection.     

The potential of genotypically diverse cultivar mixtures to moderate aphid populations in wheat (Triticum aestivum L.)

Plant species diversity has long been considered a primary driver of arthropod community structure; however, recent ecological research has demonstrated that plant genotypic diversity can also play a major role in influencing the composition of arthropod communities. Genotypic diversity has already been exploited in some agricultural systems to improve disease control and appears to hold promise for managing some insect species as well. To explore the potential for using genotypic diversity within a crop species to help manage insect pests, we used laboratory-based studies to investigate the influence of wheat (Triticum aestivum L.) genotypic diversity on aphid (Rhopalosiphum padi L.) population growth. Increasingly diverse mixtures of wheat genotypes supported lower aphid populations compared with monocultures and were equally productive as single variety plantings. In the absence of aphids, genotypic mixtures were more productive than monocultures. We also analyzed the volatile organic compounds emitted by non-infested genotypic mixtures to provide insight on a possible mechanism influencing aphid populations. Mixtures and monocultures of wheat emitted the same compounds, but mixtures emitted greater amounts of volatile compounds than monocultures. Our results suggest that genotypic mixtures can strongly influence the growth rate and size of aphid populations; therefore, cultivar mixtures appear to hold good potential to be an effective tool for managing insect pests in crop fields.     

The interplay of colour and bioacoustic traits in the differentiation of a Southeast Asian songbird complex

Morphological traits have served generations of biologists as a taxonomic indicator, and have been the main basis for defining and classifying species diversity for centuries. A quantitative integration of behavioural characters, such as vocalizations, in studies on biotic differentiation has arisen more recently, and the relative importance of these different traits in the diversification process remains poorly understood. To provide a framework within which to interpret the evolutionary interplay between morphological and behavioural traits, we generated a draft genome of a cryptic Southeast Asian songbird, the limestone wren‐babbler Napothera crispifrons. We resequenced whole genomes of multiple individuals of all three traditional subspecies and of a distinct leucistic population. We demonstrate strong genomic and mitochondrial divergence among all three taxa, pointing to the existence of three species‐level lineages. Despite its great phenotypic distinctness, the leucistic population was characterized by shallow genomic differentiation from its neighbour, with only a few localized regions emerging as highly diverged. Quantitative bioacoustic analysis across multiple traits revealed deep differences especially between the two taxa characterized by limited plumage differentiation. Our study demonstrates that differentiation in these furtive songbirds has resulted in a complex mosaic of colour‐based and bioacoustic differences among populations. Extreme colour differences can be anchored in few genomic loci and may therefore arise and subside rapidly.     

Consequences of prairie fragmentation on the progeny sex ratio of a gynodioecious species, Lobelia spicata (Campanulaceae)

Habitat fragmentation of prairie ecosystems has resulted in increased isolation and decreased size of plant populations. In large populations, frequency-dependent selection is expected to maintain genetic diversity of sex determining factors associated with gynodioecy, that is, nuclear restorer genes that reverse cytoplasmic male sterility (nucleocytoplasmic gynodioecy). However, genetic drift will have a greater influence on small isolated populations that result from habitat fragmentation. The genetic model for nucleocytoplasmic gynodioecy implies that the proportion of female progeny produced by hermaphroditic and female plants will show more extreme differences in populations with reduced allelic diversity, and that restoration of male function will increase with inbreeding. We investigated potential impacts of effects resulting from reduced population sizes by comparison of progeny sex ratios produced by female and hermaphroditic plants in small and large populations of the gynodioecious prairie species, Lobelia spicata. A four-way contingency analysis of the impact of population size, population sex ratio, and maternal gender on progeny sex ratios showed that progeny sex ratios of hermaphroditic plants were strongly influenced by population size, whereas progeny sex ratios of female plants were strongly influenced by population sex ratio. Further, analysis of variation in progeny-type distribution indicated decreased restoration and increased loss of male function in smaller and isolated populations. These results are consistent with reduced allelic diversity or low allelic frequency at restorer loci in small and isolated populations. The consequent decrease in male function has the potential to impede seed production in these fragmented prairies.     

Inter-species variation in yolk steroid levels and a cowbird-host comparison

We examined variability in yolk hormone levels among songbird species and the role of yolk steroids as a mechanism for enhanced exploitation of hosts by the parasitic brown-headed cowbird Molothrus ater . Within-clutch variation in yolk steroids has been found in several avian species in single species studies, but few comparisons have been made among species. We found a large range of differences in yolk testosterone among the seven passerine species examined, with significant differences between those at the high end (song sparrow Melospiza melodia , red-winged blackbird Agelaius phoeniceus , and house sparrow, Passer domesticus ) and those at the low end (eastern phoebe Sayornis phoebe , and house finch Carpodacus mexicanus ). We also found that the testosterone level in cowbird eggs was intermediate in relation to host species levels and was significantly lower than that in three common cowbird hosts (song sparrow, red-winged blackbird, and house sparrow), but not significantly different from three others. Geographical comparisons of yolk testosterone levels in all cowbird subspecies and populations from several regions showed no significant differences, though a trend that deserves further exploration was the pattern of lowest level in the ancestral population of cowbirds in the central prairies and of highest level in the northwestern population where range invasion occurred approximately 40 years ago. The levels of 17 beta-estradiol were similar in the seven songbird species examined, which is consistent with current hypotheses that this hormone plays a role in embryonic sexual differentiation. Further investigation is needed to determine whether the large differences observed among species in absolute level of yolk testosterone are the relevant focal point or whether target tissue sensitivity differences mediate the effects of this yolk steroid, particularly between parasitic and non-parasitic species.     

Spatial variation in adult sex ratio across multiple scales in the invasive golden apple snail,Pomacea canaliculata

Adult sex ratio (ASR) has critical effects on behavior and life history and has implications for population demography, including the invasiveness of introduced species. ASR exhibits immense variation in nature, yet the scale dependence of this variation is rarely analyzed. In this study, using the generalized multilevel models, we investigated the variation in ASR across multiple nested spatial scales and analyzed the underlying causes for an invasive species, the golden apple snail Pomacea canaliculata. We partitioned the variance in ASR to describe the variations at different scales and then included the explanatory variables at the individual and group levels to analyze the potential causes driving the variation in ASR. We firstly determined there is a significant female‐biased ASR for this species when accounting for the spatial and temporal autocorrelations of sampling. We found that, counter to nearly equal distributed variation at plot, habitat and region levels, ASR showed little variation at the town level. Temperature and precipitation at the region level were significantly positively associated with ASR, whereas the individual weight, the density characteristic, and sampling time were not significant factors influencing ASR. Our study suggests that offspring sex ratio of this species may shape the general pattern of ASR in the population level while the environmental variables at the region level translate the unbiased offspring sex ratio to the female‐biased ASR. Future research should consider the implications of climate warming on the female‐biased ASR of this invasive species and thus on invasion pattern.     

Carotenoids, colour and conservation in an endangered passerine, the hihi or stitchbird (Notiomystis cincta)

Carotenoids are essential dietary components utilized not only in pigmentation but also as immuno-stimulants and antioxidants. Reduced availability can have consequences on individual health and survival, thus making carotenoids a good indicator of environmental stress. We compared carotenoid profiles and plumage colour characteristics of an endangered passerine species in New Zealand, between its remnant island source population and two reintroduced island populations. Circulating carotenoids were predominantly lutein (mean of 82.2%) and zeaxanthin (mean of 14.8%), and these were the major carotenoids present as yellow pigments in the males' plumage. There were clear differences in total carotenoid concentrations and plumage colour among the three populations. Circulating carotenoid concentration was significantly higher in one of the reintroduced populations, and the yellow plumage of males was significantly higher in both reintroduced populations in comparison with the remnant population (reflected as a significant increase in hue). Understanding how these differences arise may be of importance to this species given the health benefits carotenoids impart and our ability to select plant species containing these compounds or artificially supplement them.     

Preen oil and bird fitness: a critical review of the evidence

The uropygial gland is a holocrine complex exclusive to birds that produces an oleaginous secretion (preen oil) whose function is still debated. Herein, I examine critically the evidence for the many hypotheses of potential functions of this gland. The main conclusion is that our understanding of this gland is still in its infancy. Even for functions that are considered valid by most researchers, real evidence is scarce. Although it seems clear that preen oil contributes to plumage maintenance, we do not know whether this is due to a role in reducing mechanical abrasion or in reducing feather degradation by keratinophilic organisms. Evidence for a function against pathogenic bacteria is mixed, as preen oil has been demonstrated to act against bacteria in vitro, but not in vivo. Nor is it clear whether preen oil can combat pathogenic bacteria on eggshells to improve hatching success. Studies on the effect of preen oil against dermatophytes are very scarce and there is no evidence of a function against chewing lice. It seems clear, however, that preen oil improves waterproofing, but it is unclear whether this acts by creating a hydrophobic layer or simply by improving plumage structure. Several hypotheses proposed for the function of preen oil have been poorly studied, such as reduction of drag in flight. Similarly, we do not know whether preen oil functions as repellent against predators or parasites, makes birds unpalatable, or functions to camouflage birds with ambient odours. On the other hand, a growing body of work shows the important implications of volatiles in preen oil with regard to social communication in birds. Moreover, preen oil clearly alters plumage colouration. Finally, studies examining the impact of preen oil on fitness are lacking, and the costs or limitations of preen‐oil production also remain poorly known. The uropygial gland appears to have several non‐mutually exclusive functions in birds, and thus is likely to be subject to several selective pressures. Therefore, future studies should consider how the inevitable trade‐offs among different functions drive the evolution of uropygial gland secretions.     

Bayesian meta-analysis of demographic parameters in three small, temperate passerines

Accurate estimates of population parameters are vital for estimating extinction risk. Such parameters, however, are typically not available for threatened populations. We used a recently developed software tool based on Markov Chain Monte Carlo methods for carrying out Bayesian inference (the BUGS package) to estimate four demographic parameters; the intrinsic growth rate, the strength of density dependence, and the demographic and environmental variance, in three species of small temperate passerines from two sets of time series data taken from a dipper and a song sparrow population, and from previously obtained frequentist estimates of the same parameters in the great tit. By simultaneously modeling variation in these demographic parameters across species and using the resulting distributions as priors in the estimation for individual species, we improve the estimates for each individual species. This framework also allows us to make probabilistic statements about plausible parameter values for small passerines temperate birds in general which is often critically needed in management of species for which little or no data are available. We also discuss how our work relates to recently developed theory on dynamic stochastic population models, and finally note some important differences between frequentist and Bayesian methods.     

Low RAPD Variation and Female-Biased Sex Ratio Indicate Genetic Drift in Small Populations of the Dioecious Conifer Taxus Baccata in Switzerland

Small populations are prone to genetic drift as a consequence of random sampling effects. We investigated whether we could detect such random sampling effects in the English yew (Taxus baccata), a dioecious conifer species occurring in scattered populations in Switzerland. Seven pairs of small and large populations were analyzed using random amplified polymorphic DNA (RAPD) marker bands from 20 individuals per population. Several genetic parameters (mean marker band frequency deviation, molecular variance, population differentiation) indicated that small populations experienced genetic drift. These genetic differences between small and large populations of yew were paralleled by an increased sex ratio bias towards a higher number of females in the small populations. Our findings support earlier assumptions that the Swiss occurrences of yew may be described as metapopulation dynamics, characterized by local colonization and extinction events leading to the observed genetic drift.     

Evidence for senescence in survival but not in reproduction in a short‐lived passerine

Senescence has been studied since a long time by theoreticians in ecology and evolution, but empirical support in natural population has only recently been accumulating. One of the current challenges is the investigation of senescence of multiple fitness components and the study of differences between sexes. Until now, studies have been more frequently conducted on females than on males and rather in long‐lived than in short‐lived species. To reach a more fundamental understanding of the evolution of senescence, it is critical to investigate age‐specific survival and reproduction performance in both sexes and in a large range of species with contrasting life histories. In this study, we present results on patterns of age‐specific and sex‐specific variation in survival and reproduction in the whinchat Saxicola rubetra, a short‐lived passerine. We compiled individual‐based long‐term datasets from seven populations that were jointly analyzed within a Bayesian modeling framework. We found evidence for senescence in survival with a continuous decline after the age of 1 year, but no evidence of reproductive senescence. Furthermore, we found no clear evidence for sex effects on these patterns. We discuss these results in light of previous studies documenting senescence in short‐lived birds. We note that most of them have been conducted in populations breeding in nest boxes, and we question the potential effect of the nest boxes on the shape of age‐reproductive trajectories.     

Integrating broad‐scale data to assess demographic and climatic contributions to population change in a declining songbird

Climate variation and trends affect species distribution and abundance across large spatial extents. However, most studies that predict species response to climate are implemented at small spatial scales or are based on occurrence‐environment relationships that lack mechanistic detail. Here, we develop an integrated population model (IPM) for multi‐site count and capture‐recapture data for a declining migratory songbird, Wilson's warbler (Cardellina pusilla), in three genetically distinct breeding populations in western North America. We include climate covariates of vital rates, including spring temperatures on the breeding grounds, drought on the wintering range in northwest Mexico, and wind conditions during spring migration. Spring temperatures were positively related to productivity in Sierra Nevada and Pacific Northwest genetic groups, and annual changes in productivity were important predictors of changes in growth rate in these populations. Drought condition on the wintering grounds was a strong predictor of adult survival for coastal California and Sierra Nevada populations; however, adult survival played a relatively minor role in explaining annual variation in population change. A latent parameter representing a mixture of first‐year survival and immigration was the largest contributor to variation in population change; however, this parameter was estimated imprecisely, and its importance likely reflects, in part, differences in spatio‐temporal distribution of samples between count and capture‐recapture data sets. Our modeling approach represents a novel and flexible framework for linking broad‐scale multi‐site monitoring data sets. Our results highlight both the potential of the approach for extension to additional species and systems, as well as needs for additional data and/or model development.