David B Lank

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• PhD Cornell University
• Researcher at Simon Fraser University

Androgens are pleiotropic and play pivotal roles in the formation and variation of sexual phenotypes. We show that differences in circulating androgens between the three male mating morphs in ruff sandpipers are linked to 17-beta hydroxysteroid dehydrogenase 2 (HSD17B2), encoded by a gene within the supergene that determines the morphs. Low-testost...

The ruff sandpiper (Calidris pugnax) is a lekking shorebird with three male morphs that differ remarkably in behavior, ornaments, size, and endocrinology. The morphs are determined by an autosomal inversion. Aggressive Independents evolved first, female-mimicking Faeders ~4 mil year ago when a short segment of a chromosome reversed in orientation,...

Species with alternative reproductive tactics typically show pronounced phenotypic variation between and within sexes. In some species, this variation culminates in discrete reproductive morphs that are genetically determined, facilitating studies on how genetic variation translates into phenotypic variation. In ruffs (Calidris pugnax), an autosoma...

Seasonally abundant arthropods are a crucial food source for many migratory birds that breed in the Arctic. In cold environments, the growth and emergence of arthropods are particularly tied to temperature. Thus, the phenology of arthropods is anticipated to undergo a rapid change in response to a warming climate, potentially leading to a trophic m...

Global climate change has altered the timing of seasonal events (i.e., phenology) for a diverse range of biota. Within and among species, however, the degree to which alterations in phenology match climate variability differ substantially. To better understand factors driving these differences, we evaluated variation in timing of nesting of eight A...

We tested the influence of on-shore avian predators on the at-sea distribution and abundance of marbled murrelets (Brachyramphus marmoratus) during their breeding season in Haida Gwaii, British Columbia, Canada. We conducted a field experiment using deterrent predator decoy kites that mimicked flying bald eagles (Haliaeetus leucocephalus). In the s...

This book brings together the results from one of the most significant long-term studies of birds in the late twentieth century, testing our understanding of evolution in natural populations. Combining genetics, behavior, ecology, and a landmark data set, it will be essential reading for everyone with an interest in evolutionary ecology. The Lesser...

Mercury (Hg) pollution remains a concern to Arctic ecosystems, due to long-range transport from southern industrial regions and melting permafrost and glaciers. The objective of this study was to identify intrinsic, extrinsic, and temporal factors influencing Hg concentrations in Arctic-breeding shorebirds and highlight regions and species at great...

Background The ruff sandpiper Calidris pugnax is a Palearctic lekking shorebird with three genetic morphs determined by an autosomal inversion. Male morphs differ strikingly in body size, ornaments, endocrinology and mating behavior. Aggressive Independents represent the ancestral haplotype, while female-mimicking Faeders and semi-cooperative Satel...

Increasing predation danger can select for safety-enhancing modifications to prey morphology. Here, we document the multi-decade wing lengthening of a Pacific flyway migrant, the western sandpiper (Calidris mauri), and contrast this with contemporaneous wing shortening of the closely related semipalmated sandpiper (C. pusilla) on the Atlantic flywa...

Mercury (Hg) pollution remains a concern to Arctic ecosystems. The objective of this study was to identify factors influencing Hg concentrations in Arctic-breeding shorebirds and highlight regions and species at greatest risk of Hg exposure. We analyzed 2,478 blood and feather samples from 12 shorebird species breeding at nine sites across the Nort...

link to article, free access till March 24 2023: https://authors.elsevier.com/a/1gWwnmjL%7EduK Male–male competition over matings is a key driving force in the evolution of courtship. Typically, male–male competition is an individual affair selecting for dominance and aggression. Yet, some males forgo direct confrontation improving their reproduct...

Reproductive phenotypes are shaped by genetic, physiological and environmental variation that an organism experiences during ontogeny. Steroid hormones play an integrative role in this process through both genomic and non-genomic pathways. Differences in steroid hormone metabolism may be rooted in genomic variation. Here we evaluate the influence o...

The Marbled Murrelet Brachyramphus marmoratus is a threatened seabird that relies on old-growth forest for nesting. We compare marine space use between breeding and non-breeding birds, and how marine home range locations and overlap vary with respect to nesting location and breeding status. We collected very high frequency (VHF) radio-telemetry dat...

Male-male competition over matings is a key driving force in the evolution of courtship. Typically, competition is an individual affair selecting for dominance and aggression. Yet, some males forgo direct confrontation and improve their reproductive success through cooperation. Occasionally, this leads to specialized alternative reproductive tactic...

Two recent and independent studies both estimate substantially lower survival rates of semipalmated Calidris pusilla than of western C. mauri sandpipers, consistent with the pronounced multi‐decade population decline of the former. Migratory danger has climbed steadily for both these long‐distance migrants since the mid‐1970s as the number of pereg...

Chromosomal inversions frequently underlie major phenotypic variation maintained by divergent selection within and between sexes. Here we examine whether and how intralocus conflicts contribute to balancing selection stabilizing an autosomal inversion polymorphism in the ruff Calidris pugnax. In this lekking shorebird, three male mating morphs (Ind...

The Marbled Murrelet (Brachyramphus marmoratus) is a small seabird that is currently listed as threatened in Canada. Understanding this species’ marine habitat preferences plays a vital role in our ability to focus conservation planning. We used the longest-running at-sea survey dataset available in British Columbia to examine hotspot persistence a...

Chromosomal inversions frequently underlie major phenotypic variation maintained by divergent selection within and between sexes. Here we examine whether and how intralocus conflicts contribute to balancing selection stabilizing an autosomal inversion polymorphism in the ruff Calidris pugnax. In this lekking shorebird, three male mating morphs (Ind...

Chromosomal inversions are structural rearrangements that frequently provide genomic substrate for phenotypic diversity. In the ruff Philomachus pugnax, three distinct male reproductive morphs (Independents, Satellites and Faeders) are genetically determined by a 4.5 Mb autosomal inversion. Here we test how this stable inversion polymorphism affect...

Average annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of s...

The evolution of social behavior depends on genetic changes, yet, how genomic variation manifests itself in behavioral diversity is still largely unresolved. Chromosomal inversions can play a pivotal role in producing distinct behavioral phenotypes, in particular, when inversion genes are functionally associated with hormone synthesis and signaling...

Background Age at maturity and the timing of first breeding are important life history traits. Most small shorebird species mature and breed as ‘yearlings’, but have lower reproductive success than adults. In some species, yearlings may defer northward migration and remain in non-breeding regions (‘oversummering’) until they reach 2 years of age. S...

The evolutionary and behavioural ecology of migratory birds has received much theoretical and empirical attention. We contribute to this field by contrasting the weather at departure and stopover durations of a long‐distance migratory sandpiper prior to initiating lengthy transoceanic vs. transcontinental flights of potentially variable duration. T...

Many shorebirds (Order: Charadriiformes; Family: Charadriidae, Recurvirostridae, Scolopacidae, Haematopodidae, Jacanidae) are highly migratory, traversing thousands of kilometers between high latitude breeding and low latitude nonbreeding sites. In doing so, they are dependent on networks of coastal and interior wetland ecosystems. To aid in the ef...

Conservation status and management priorities are often informed by population trends. Trend estimates can be derived from population surveys or models, but both methods are associated with sources of uncertainty. Many Arctic-breeding shorebirds are thought to be declining based on migration and/or overwintering population surveys, but data are lac...

The evolution of social behavior depends on genetic changes, yet, how genomic variation manifests itself in behavioral diversity is still largely unresolved. Chromosomal inversions can play a pivotal role in producing distinct behavioral phenotypes, in particular, when inversion genes are functionally associated with hormone synthesis and signaling...

Most studies on sexual size dimorphism address proximate and functional questions related to adults, but sexual size dimorphism usually develops during ontogeny and developmental trajectories of sexual size dimorphism are poorly understood. We studied three bird species with variation in adult sexual size dimorphism: black coucals (females 69% heav...

Peregrine falcons (Falco peregrinus) have undergone a steady hemisphere-wide recovery since the ban on DDT in 1973, resulting in an ongoing increase in the level of danger posed for migrant birds, such as Arctic-breeding sandpipers. We anticipate that in response migrant semipalmated sandpipers (Calidris pusilla) have adjusted migratory behavior, i...

Chewing lice often appear benign; however, they can also negatively impact their hosts. We know little about seasonal and spatial variation in the exposure, acquisition, or loss of these putative ectoparasites by shorebirds. Here we provide the first description of chewing lice richness and occurrence from seven shorebird species captured in the Pa...

Peregrine falcons ( Falco peregrinus ) have undergone a steady hemisphere-wide recovery since the ban on DDT in 1973, resulting in an ongoing increase in the level of danger posed for migrant birds, such as Arctic-breeding sandpipers. We anticipate that in response migrant semipalmated sandpipers ( Calidris pusilla ) have adjusted migratory behavio...

Responses to climate change can vary across functional groups and trophic levels, leading to a temporal decoupling of trophic interactions or “phenological mismatches.” Despite a growing number of single‐species studies that identified phenological mismatches as a nearly universal consequence of climate change, we have a limited understanding of th...

Supernormal clutches are found across bird species. Such clutches often result from more than one female laying eggs in the same nest and can reflect different behaviours from parasitism to laying mistakes. Enlarged clutches are readily visible among waders due to a maximum maternal clutch size of four eggs, yet surprisingly little is known about t...

Marking wild birds is an integral part of many field studies. However, if marks affect the vital rates or behavior of marked individuals, any conclusions reached by a study might be biased relative to the general population. Leg bands have rarely been found to have negative effects on birds and are frequently used to mark individuals. Leg flags, wh...

Identifying and mapping suitable nesting habitat within coastal forests is a key element in the recovery and management of the Marbled Murrelet (Brachyramphus marmoratus), which is listed as Threatened in Canada. This article reviews the reliability and application of three primary methods used to assess habitat suitability: the BC Model, a GIS-bas...

Seasonal declines in breeding performance are widespread in wild animals, resulting from temporal changes in environmental conditions or from individual variation. Seasonal declines might drive selection for early breeding, with implications for other stages of the annual cycle. Alternatively, selection on the phenology of nonbreeding stages could...

Telomeres are highly conserved regions of DNA that protect the ends of linear chromosomes. The loss of telomeres can signal an irreversible change to a cell's state, including cellular senescence. Senescent cells no longer divide and can damage nearby healthy cells, thus potentially placing them at the crossroads of cancer and ageing. While the epi...

Many Arctic shorebird populations are declining, and quantifying adult survival and the effects of anthropogenic factors is a crucial step toward a better understanding of population dynamics. We used a recently developed, spatially explicit Cormack-Jolly-Seber model in a Bayesian framework to obtain broad-scale estimates of true annual survival ra...

The Arctic is experiencing rapidly warming temperatures, increasing predator abundance, and diminishing population cycles of keystone species such as lemmings. However, it is still not known how many Arctic animals will respond to a changing climate with altered trophic interactions. We studied clutch size, incubation duration, and nest survival of...

Biological impacts of climate change are exemplified by shifts in phenology. As the timing of breeding advances, the within-season relationships between timing of breeding and reproductive traits may change and cause long-term changes in the population mean value of reproductive traits. We investigated long-term changes in the timing of breeding an...

Seasonal declines in breeding performance are widespread in wild animals, resulting from temporal changes in environmental conditions or from individual variation. Seasonal declines might drive selection for early breeding, with implications for other stages of the annual cycle. Alternatively, selection on the phenology of nonbreeding stages could...

Semipalmated Sandpiper (Calidris pusilla) populations have undergone significant declines at core nonbreeding sites in northeastern South America. Breeding populations have also declined in the eastern North American Arctic, but appear to be stable or increasing in the central and western Arctic. To identify vulnerable populations and sites, we doc...

Large-scale changes in predator populations are occurring worldwide due to (re-)introductions, over-exploitation, or recovery after decimation by pesticides and persecution. These widespread changes may affect the distribution of their prey. We studied the continental-scale distributions of non-breeding Calidris alpina pacifica and C. a. hudsonia (...

We compiled a >50-year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collec...

We placed wire mesh predator exclosures around the nests of Red-necked Phalaropes Phalaropus lobatus at a tundra site outside of Nome, Alaska, in 2011 and 2012. Exclosures were made of 2.5 cm × 5.1 cm wire mesh and were approximately 0.8 m high, 0.8 m in diameter, with a flat top, and were secured to the ground with three metal stakes. We compared...

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, c...

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1-4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1,5, but free-living individuals have to temporally synchronize their activities with those of others, including potential ma...

Migration distances of shorebird species correlate with life history strategies. To assess age-specific migratory preparation and adult wing-molt strategies, we studied Western Sandpipers (Calidris mauri) and Semipalmated Sandpipers (C. pusilla) with different migration routes at the Paracas National Reserve in Perú, one of the most austral non-bre...

Background Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2–4 subspecies each for a total of...

Three strikingly different alternative male mating morphs (aggressive 'independents', semicooperative 'satellites' and female-mimic 'faeders') coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosoma...

In mark-recapture studies conducted on fixed-area study sites, apparent (or "local") survival (φ) is the product of the probabilities of true survival (S) and site fidelity to the sampling area (F). If marked individuals permanently emigrate from the study site, apparent survival will be biased low relative to true survival. Similarly, estimates of...

Shorebirds have wide variation in life history strategies. Among and within species, greater migration distances relate to slow “oversummering” versus fast strategies, assessed by juveniles’ propensity to migrate and breed during the first spring. As indices of age-specific migratory preparation from one of the most austral non-breeding areas, we c...

Understanding the forces driving population dynamics is critical for species conservation and population management. For migratory birds, factors that regulate population abundance could come from effects experienced on breeding areas, wintering grounds, or during migration. We compiled survey data for Pacific and Atlantic subspecies of dunlins (Ca...

Sequence variation in the melanocortin-1 receptor (MC1R) gene explains color morph variation in several species of birds and mammals. Ruffs (Philomachus pugnax) exhibit major dark/light color differences in melanin-based male breeding plumage which is closely associated with alternative reproductive behavior. A previous study identified a microsate...

Fisher's sex ratio theory predicts that on average parents should allocate resources equally to the production of males and females. However, when the cost/benefit ratio for producing males versus females differs, the theory predicts that parents may bias production, typically through underproduction of the sex with greater variation in fitness. We...

Theory predicts that if extending parental care delays migratory departure, and if later migration is more dangerous, then parental care should be curtailed to make an earlier departure. Adult western sandpipers (Calidris mauri) depart Alaska in July, and the presence of peregrine falcons (Falco peregrinus) along their route rises steeply during th...

Sex differences in skews of vertebrate lifetime reproductive success are difficult to measure directly. Evolutionary histories of differential skew should be detectable in the genome. For example, male-biased skew should reduce variation in the biparentally inherited genome relative to the maternally inherited genome. We tested this approach in lek...

Males of many species theoretically face a fitness tradeoff between mating and parental effort, but quantification of this is rare. We estimated the magnitude of the mating opportunity cost paid by incubating male Temminck’s stints (Calidris temminckii), taking advantage of uniparental care provided by both sexes in this species. “Incubating males”...

Ecological theory for long-distance avian migration considers time-, energy-, and mortality-minimizing tactics, but predictions about the latter have proven elusive. Migrants must make behavioral decisions that can favor either migratory speed or safety from predators, but often not both. We compare the behavior of adult and juvenile western sandpi...

With a population estimate of approximately 3.5 million individuals (Bishop et al. 2000), the Western Sandpiper is one of the most abundant shorebirds in the Western Hemisphere, despite its restricted breeding range in coastal tundra regions of western Alaska and far-eastern Siberia. The majority of the global population spends the boreal winter i...

Maintaining polymorphisms for genes with effects of ecological significance may involve conflicting selection in males and females. We present data from a captive population of ruffs (Philomachus pugnax) showing that a dominant allele controls development into both small, ‘female mimic’ males (‘faeders’), and a previously undescribed class of small...

Ruffs (Aves: Philomachus pugnax) possess a genetic polymorphism for male mating behaviour resulting in three permanent alternative male reproductive morphs: (i) territorial 'Independents', (ii) non-territorial 'Satellites', and (iii) female-mimicking 'Faeders'. Development into independent or satellite morphs has previously been shown to be due to...

Many bird species show spatial or habitat segregation of the sexes during the non-breeding season. One potential ecological explanation is that differences in bill morphology favour foraging niche specialisation and segregation. Western sandpipers Calidris mauri have pronounced bill size dimorphism, with female bills averaging 15% longer than those...

A linkage map of the ruff (Philomachus pugnax) genome was constructed based on segregation analysis of 58 microsatellite loci from 381 captive-bred individuals spanning fourteen breeding years and comprising 64 families. Twenty-eight of the markers were resolved into seven linkage groups and five single marker loci, homologous to known chicken (Gal...

On the western coast of North America, several estuaries provide shorebirds with important winter and stopover habitat. These habitats include not only aquatic estuarine resources but also adjacent upland agricultural lands. The extent to which shorebirds use estuarine vs. upland habitats at these stopover sites is difficult to quantify but crucial...

Immunity and resistance to oxidative stress are two mechanistically related aspects of self-maintenance that are usually not studied together in connection to ecological or evolutionary relevant variables. Whereas many studies compare two sexes, here we use Ruffs (Philomachus pugnax (L., 1758)), a species in which males have three alternative repro...

Immunity and resistance to oxidative stress are two mechanistically related aspects of self-maintenance that are usually not studied together in connection to ecological or evolutionary relevant variables. Whereas many studies compare two sexes, here we use Ruffs (Philomachus pugnax (L., 1758)), a species in which males have three alternative repro...

Immunosenescence, the decline of immune function with age, results in increased risk of infection as an individual ages. The underlying reasons are still poorly understood. Here, we ask whether the rate of decline of an immune indicator is positively correlated with the cost of maintaining it, as predicted by optimal resource allocation theory. Usi...

By next generation transcriptome sequencing, it is possible to obtain data on both nucleotide sequence variation and gene expression. We have used this approach (RNA-Seq) to investigate the genetic basis for differences in plumage coloration and mating strategies in a non-model bird species, the ruff (Philoma-chus pugnax). Ruff males show enormous...

By next generation transcriptome sequencing, it is possible to obtain data on both nucleotide sequence variation and gene expression. We have used this approach (RNA-Seq) to investigate the genetic basis for differences in plumage coloration and mating strategies in a non-model bird species, the ruff (Philomachus pugnax). Ruff males show enormous v...

Nonbreeding shorebirds often alternate social structure between anonymous flocks and territorial behavior in response to different environmental factors. To evaluate specific drivers for one species, we studied the spacing behavior of wintering Western Sandpipers (Calidris mauri) at Bahia Santa Maria, northwestern Mexico, using behavioral observati...

We identified 247 unique ruff (Philomachus pugnax) microsatellite sequences. Primer sets were designed from 102 selected loci and tested in 12–24 individuals from a captive population. Sequence homology was used to assign locations in the chicken (Gallus gallus) and/or zebra finch (Taeniopygia guttata) genome for the majority of these loci. Fifty-t...