Lower survival of hybrid grosbeaks, but not towhees, suggests a molt divide disfavors hybrids.

Although avian hybrid zones in the Great Plains have been studied for almost 70 years, we know surprisingly little about the fitness costs to hybrids that keep these zones narrow. We compare age ratios in grosbeaks (Pheucticus ludovicianus and P. melanocephalus) and towhees (Pipilo erythropthalums and P.

Geographic variability of hybridization between red-breasted and red-naped sapsuckers.

Hybrid zones reveal the strength of reproductive isolation between populations undergoing speciation and are a key tool in evolutionary biology research. Multiple replicate transects across the same hybrid zone offer insight into the dynamics of hybridization in different environments, clarifying the role of extrinsic forces on the speciation process. Red-breasted and red-naped sapsuckers (Sphyrapicus ruber and Sphyrapicus nuchalis) have a long zone of contact over approximately 1,600 km from central British Columbia, Canada to central California, USA.

Historical DNA as a tool to address key questions in avian biology and evolution: A review of methods, challenges, applications, and future directions.

Museum specimens play a crucial role in addressing key questions in systematics, evolution, ecology, and conservation. With the advent of high-throughput sequencing technologies, specimens that have long been the foundation of important biological discoveries can inform new perspectives as sources of genomic data. Despite the many possibilities associated with analyzing DNA from historical specimens, several challenges persist.

Phenotypic and genetic introgression across a moving woodpecker hybrid zone.

In hybrid zones in which two divergent taxa come into secondary contact and interbreed, selection can maintain phenotypic diversity despite widespread genetic introgression. Red-breasted (Sphyrapicus ruber) and red-naped (S. nuchalis) sapsuckers meet and hybridize along a narrow contact zone that stretches from northern California to southern British Columbia.

Changing climate mediates sapsucker (Aves: ) hybrid zone movement.

Hybrid zones, where two divergent taxa meet and interbreed, offer unique opportunities to investigate how climate contributes to reproductive isolation between closely related taxa and how these taxa may respond to climatic changes. Red-naped () and Red-breasted () sapsuckers (Aves: Picidae) hybridize along a narrow contact zone that stretches from northern California to British Columbia. The hybrid zone between these species has been studied extensively for more than 100 years and represents an excellent system for investigations of the evolution of reproductive isolation.

How spatio-temporal habitat connectivity affects amphibian genetic structure.

Heterogeneous landscapes and fluctuating environmental conditions can affect species dispersal, population genetics, and genetic structure, yet understanding how biotic and abiotic factors affect population dynamics in a fluctuating environment is critical for species management. We evaluated how spatio-temporal habitat connectivity influences dispersal and genetic structure in a population of boreal chorus frogs (Pseudacris maculata) using a landscape genetics approach. We developed gravity models to assess the contribution of various factors to the observed genetic distance as a measure of functional connectivity.

Low variation in the polymorphic Clock gene poly-Q region despite population genetic structure across barn swallow (Hirundo rustica) populations.

Recent studies of several species have reported a latitudinal cline in the circadian clock gene, Clock, which influences rhythms in both physiology and behavior. Latitudinal variation in this gene may hence reflect local adaptation to seasonal variation. In some bird populations, there is also an among-individual association between Clock poly-Q genotype and clutch initiation date and incubation period.