Asymmetrical gene flow of the recently delisted passerine black‐capped vireo (Vireo atricapilla) indicates source‐sink dynamics in central Texas

Habitat fragmentation can produce metapopulations or source‐sink systems in which dispersal in crucial for population maintenance. Our objective was to investigate connectivity among black‐capped vireo (Vireo atricapilla) populations in tandem with a demographic study (Biological Conservation, 2016, 203, 108–118) to elucidate if central Texas populations act as a source‐sink system. We genotyped 343 individuals at 12 microsatellite loci to elucidate the movement ecology of the black‐capped vireo in central Texas surrounding Fort Hood; the largest and most stable breeding population of black‐capped vireos inhabit Fort Hood. To gain insight into gene flow among populations, we analyzed genetic differentiation, migration rates, number of migrants, and parentage. We found statistically significant, but low levels of genetic differentiation among several populations, suggesting some limited restriction to gene flow. Across approaches to estimate migration, we found consistent evidence for asymmetrical movement from Fort Hood to the other central Texas sites consistent with source‐sink dynamics. Our results are complementary to black‐capped vireo demographic studies done in tandem showing that portions of Fort Hood are acting as a source population to smaller central Texas populations.     

A distinctive new species of vireo (Passeriformes: Vireonidae) from the Western Andes of Colombia

On the basis of field observations and two specimens from two localities in the Chocó biogeographic region of western Colombia, we here describe Vireo masteri, sp. nov. This species appears to be most closely related to Vireo carmioli of Costa Rica and west Panama but is much smaller and has a distinctive long superciliary stripe, a feature otherwise unknown in the subgenus Vireo, of which it is the southernmost known taxon. Vireo masteri appears to be restricted to a narrow belt of premontane pluvial forests from 1200 to 1600 m on the Pacific slope of the Western Andes. We present notes on the behaviour, ecology and conservation of this new species. Con base en observaciones en el campo y dos especímenes de dos localidades en la región biogeográfica del Chocó colombiano, describimos una nueva y distintiva especie de vireo o chiví, Vireo masteri, sp. nov. Esta especie parece mas afin a Vireo carmiloi de Costa Rica y Panamá que a cualquier otra especie, pero es de menor tamaño y tiene una lista superciliar larga y llamativa, caracteristica única en la subgénero Vireo, del cual es la forma más sureña. Vireo masteri aparentemente se restringe a una faja altitudinal angosta (1200–1600 msnm) de bosque pluvial premontano en la vertiente del Pacífico de la Cordillera Occental de los Andes colombianos. Presentamos anotaciones sobre la ecología, el comportamiento, y la conservación de esta neueva especie.     

Response of Captive Raptors to Avian Mobbing Calls: the Roles of Mobber Size and Raptor Experience

The ‘move on’ hypothesis for avian mobbing proposes that mobbing induces stress in potential predators, thereby provoking them into moving elsewhere. We tested whether mobbing is stress inducing by subjecting captive owls, hawks, and falcons to the mobbing calls of four species of co‐occurring passerine birds that vary considerably in body size. Test subjects comprised 15 individuals of seven species of birds of prey that were housed at a wildlife rehabilitation center in northwestern Pennsylvania, USA. Playback treatments included mobbing calls of the black‐capped chickadee (Poecile atricapillus), blue‐headed vireo (Vireo solitarius), blue jay (Cyanocitta cristata), and American crow (Corvus brachyrhynchos), which vary in size from 12 g (chickadee) to 500 g (crow). A non‐mobbing vocalization (song of the black‐capped chickadee) was included in the playback treatments as a control. Playback treatment produced pronounced effects on three behavioral indicators of probable stress: head orientation toward the playback speaker, raising of feathers or spreading of wings, and changing of perch positions. Test subjects responded more vigorously to mobbing calls of the large passerines (jays and crows) than to those of the smaller passerines (chickadees and vireos). In addition, raptors that had entered the rehabilitation facility as adults generally responded more vigorously to the mobbing calls of jays and crows than did naive individuals that had entered the facility as fledglings or young juveniles. Our results are therefore consistent with the ‘move on’ hypothesis and suggest (1) that the mobbing calls of large passerines are more effective in provoking stress and altering the behavior of potential predators than are the mobbing calls of small passerines and (2) that a raptor's previous experience with mobbing in the wild can exaggerate the strength of its response, particularly to the mobbing calls of large passerines.     

Fluctuating fire regimes and their historical effects on genetic variation in an endangered shrubland specialist

The Pleistocene was characterized by worldwide shifts in community compositions. Some of these shifts were a result of changes in fire regimes, which influenced the distribution of species belonging to fire‐dependent communities. We studied an endangered juniper–oak shrubland specialist, the black‐capped vireo (Vireo atricapilla). This species was locally extirpated in parts of Texas and Oklahoma by the end of the 1980s as a result of habitat change and loss, predation, brood parasitism, and anthropogenic fire suppression. We sequenced multiple nuclear loci and used coalescence methods to obtain a deeper understanding of historical population trends than that typically available from microsatellites or mtDNA. We compared our estimated population history, a long‐term history of the fire regime and ecological niche models representing the mid‐Holocene, last glacial maximum, and last interglacial. Our Bayesian skyline plots showed a pattern of historical population fluctuation that was consistent with changing fire regimes. Genetic data suggest that the species is genetically unstructured, and that the current population should be orders of magnitude larger than it is at present. We suggest that fire suppression and habitat loss are primary factors contributing to the recent decline of the BCVI, although the role of climate change since the last glacial maximum is unclear at present.     

Cedar Infestation Impacts Avian Communities along the Niobrara River Valley,Nebraska

Habitat modification has the potential to cause changes in structure and composition of bird communities. Our goal was to determine the response of Songbird community composition to eastern red cedar (Juniperus virginiana) removal in The Nature Conservancy's Niobrara Valley Preserve, Nebraska. We used point counts to survey birds in the riparian matrix of grassland and forest habitats. More than 60 species were recorded on surveys during 2004–2005. We also use the program PRESENCE to determine the response of five species to various habitat components, including cedar density: House Wren (Troglodytes aedon), Spotted Towhee (Pipilo maculates), Ovenbird (Seiurus aurocapillus), Red‐eyed Vireo (Vireo olivaceus), and Indigo Bunting (Passerina cyanea). Species richness estimates were highest in open and mixed habitat patches. Local populations of Ovenbirds and Red‐eyed Vireos responded positively to cedar density, whereas House Wren numbers declined as cedar density increased. Cedar abundance explained the most variation in bird community similarity between survey points; species richness increased as cedar density decreased. Habitat structure and composition drove variation in community composition and population abundance at fine, local scales within the Preserve. Fine‐scale management to remove cedar from local areas should increase diversity of avian species by maintaining a matrix of habitat types. Cedar removal at any scale will affect the composition of bird communities, and we encourage a structured approach to management decisions.     

Novel polymorphic microsatellite markers for paternity analysis in the red‐capped robin (Petroica goodenovii: Aves)

Seven microsatellite loci were isolated and characterized from the red‐capped robin Petroica goodenovii, using nonradioactive polymerase chain reaction (PCR)‐based techniques to screen an enriched genomic library. Five loci showed no evidence of null alleles and were variable [mean heterozygosity (H_E) = 0.440, mean number of alleles = 8]. Cross‐amplification using primers for microsatellites in Phylloscopus occipitalis and Emberiza schoeniclus yielded another two polymorphic loci. The combined set of five red‐capped robin and two cross‐amplified loci are suitable for paternity assignment (exclusion probability for seven unlinked loci = 0.9760).     

Novel microsatellite loci identified from the Australian eastern small‐eyed snake (Elapidae: Rhinocephalus nigrescens) and cross species amplification in the related genus Suta

A total of 15 microsatellite primers pairs were developed for the Australian small‐eyed snake Rhinoplocephalus nigrescens. Five primers were used to screen 93 individuals of R. nigrescens and were also tested against eight species of the closely related genus Suta. Allelic diversity in R. nigrescens was high in three loci (12–27) and there was high heterozygosity (0.58–0.82). Observed heterozygosity did not deviate from Hardy–Weinberg expectations for the five loci tested. These primers will be useful in studies of population genetics and mating systems of small‐eyed snakes and related species.     

Polymorphic microsatellite loci from the American goldfinch (Carduelis tristis) and their cross‐amplification in a variety of passerine species

Cardueline finches have become important models in studies of sexual selection. Here I describe eight polymorphic microsatellite loci isolated from the American goldfinch (Carduelis tristis) that are useful in parentage and heterozygosity studies. The number of alleles per locus ranged from eight to 38 based on 252 goldfinches. The markers are polymorphic in at least four other Cardueline finch species, and several amplify in nonfinch passerines including red‐winged blackbird (Agelaius phoeniceus), black‐throated blue warbler (Dendroica caerulescens) and tufted titmouse (Baeolophus bicolor), indicating they should be useful in paternity and population studies of a variety of species.     

Isolation and characterization of polymorphic microsatellite markers in the white‐winged chough (Corcorax melanorhamphos)

We have isolated and characterized seven polymorphic microsatellite loci in the white‐winged chough (Corcorax melanorhamphos), a highly social, cooperatively breeding bird of Australian eucalypt woodlands. In analyses of 100 samples from 16 family groups, the number of alleles per locus ranged from four to 18, and observed heterozygosity ranged between 0.46 and 0.93. One locus appears to be sex‐linked. The primers were also tested in apostlebirds (Struthidera cinerea), the only other species in the subfamily Corcoracinae. Five loci were successfully amplified and three were polymorphic.     

Brood parasitism of Black‐capped Vireos: frontline and post‐laying behavioral responses and effects on productivity

The cost of brood parasitism favors the evolution of host behaviors that reduce the risk or expense of being parasitized. Endangered Black‐capped Vireos (Vireo atricapilla) have likely coexisted with brood‐parasitic Brown‐headed Cowbirds (Molothrus ater) for more than 10,000 yr, so it is likely that they have evolved anti‐parasitic behaviors. We monitored naturally parasitized and non‐parasitized vireo nests to evaluate factors that might explain parasitism risk and nest desertion behavior and also assessed whether behaviors that occurred after being parasitized improved reproductive output. Vireos reduced the risk of parasitism by initiating breeding early and nesting farther from open grasslands and edges of woody thickets. Post‐laying, nest desertion was common (70% of parasitized nests) and increased with both the presence of at least one cowbird egg in nests and clutch reduction by cowbirds. After accounting for these cues, desertion was also more likely at nests located closer to cowbird foraging habitat and below potential cowbird vantage points. Despite its regularity, desertion did not appear to provide reproductive benefits to vireos. Instead, accepting cowbird eggs was a more effective strategy because 42% of cowbird eggs did not hatch. Furthermore, cowbird eggs were somehow ejected from at least three vireo nests. Our results suggest that Black‐capped Vireos can behave in a variety of ways that reduce the impact of brood parasitism, with frontline behaviors appearing to provide the greatest benefit. Our results also suggest that habitat management should focus on providing Black‐capped Vireos with adequate breeding habitat that provides access to safe nesting sites, and with high‐quality wintering habitat that allows vireos to migrate and initiate nesting early.     

Microsatellite DNA markers for the Chinese wood frog (Rana chensinensis) and tests for their cross-utility in 15 ranid frog species

We developed 22 microsatellite markers for the Chinese wood frog (Rana chensinensis) to study the impact of landscape features on its population structure. Thirty‐four individuals from one breeding site were examined and 14 loci were polymorphic. The number of alleles, expected heterozygosity and observed heterozygosity varied from two to 14, from 0.0833 to 0.9118, and from 0.1376 to 0.8667, respectively. Cross‐species amplification was tested for 15 ranid frog species. The Plateau brown frog, Rana kukunoris (n = 23), was successfully amplified at 18 loci, and 15 were polymorphic with number of alleles varying from two to 18. Ten other species were also amplified at a limited number of loci.     

Characterization of polymorphic microsatellite loci in a neotropical wood‐quail,Odontophorus leucolaemus

We developed a set of nine polymorphic microsatellite loci for black‐breasted wood‐quail, Odontophorus leucolaemus. We screened 50 individuals from Monteverde, Puntarenas Province, Costa Rica and found that locus‐specific allelic diversity ranges from two to 15 alleles (mean 10.2) and observed heterozygosity ranges from 0.24 to 0.96 (mean 0.78). These markers appear to be useful in other members of the Odontophorus genus.     

Microsatellite primers for the African mole‐rat genus Cryptomys and cross‐species amplification within the family Bathyergidae

We report 11 microsatellite loci for the African mole‐rat genus Cryptomys (Rodentia: Bathyergidae), isolated from the Damaraland mole‐rat (Cryptomys damarensis) and the Common mole‐rat (C. hottentotus hottentotus). All loci are highly polymorphic in the source species, with between six and 13 alleles and observed heterozygosity ranging from 0.54 to 0.86. Two C. damarensis loci (DMR1 and 6) may be located on the X‐chromosome. Cross‐species amplification was investigated in 10 Bathyergid species, representative of the five genera. The majority of loci amplified polymorphic product in all Cryptomys species tested. Amplification was also widespread in the other genera, except in Heterocephalus.     

Development of microsatellite markers in Acer capillipes

Acer capillipes is an insect‐pollinated tree species that grows in temperate regions of Japan. We isolated seven polymorphic microsatellite loci from this species using a dual‐suppression polymerase chain reaction (PCR) technique. The number of alleles per locus ranged from two to 10, and the expected heterozygosity ranged from 0.042 to 0.828. Cross‐species amplification from 14 other Acer species was successful for the majority of the isolated loci, suggesting that these loci may be useful for the characterization of other maple species.     

Isolation and characterization of polymorphic microsatellite loci in the lance‐tailed manakin (Chiroxiphia lanceolata)

Eight microsatellite loci were isolated from the lance‐tailed manakin (Chiroxiphia lanceolata), a polygynous lek‐breeding bird from Central America. Five of these loci were polymorphic (two to seven alleles per locus), with observed levels of heterozygosity ranging from 0.100 to 0.860 (n = 50 individuals). These variable loci provide a valuable tool for assessing patterns of parentage and relatedness within lance‐tailed manakin social groups.     

PCR primers for polymorphic microsatellite loci in the plant‐ant Azteca ulei cordiae (Formicidae: Dolichoderinae)

Twelve microsatellite loci were isolated from the Peruvian tropical plant‐ant, Azteca ulei cordiae (Hymenoptera: Dolichoderinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from four to 18, and heterozygosity from 0.118 to 1 per population sample. Cross‐species amplification of these loci was also successfully tested in several other species of the same ant genus Azteca.     

Isolation and characterization of polymorphic microsatellites in the tropical plant‐ant Cataulacus mckeyi (Formicidae: Myrmicinae)

Eleven microsatellite loci were isolated from the plant‐ant Cataulacus mckeyi (Hymenoptera: Myrmicinae) and their polymorphism was characterized. High levels of within‐population variation were observed at most loci, with number of alleles ranging from one to 16, and heterozygosity from 0 to 0.929 per population sample. Cross‐species amplification of these loci was also tested in four other species of the ant genus Cataulacus.     

Isolation and characterization of polymorphic microsatellite loci in Acanthoscelides obvelatus Bridwell (Coleoptera: Bruchidae)

Five microsatellite loci were isolated from the bruchid Acanthoscelides obvelatus Bridwell (Coleoptera: Bruchidae). Each locus was polymorphic, with the number of alleles ranging from two to 15. We found high levels of within‐population variation at most loci, with heterozygosity ranging from 0.182 to 0.900. Cross‐species amplification of these loci was tested in two other species of the genus Acanthoscelides, A. obtectus Say and A. argillaceus Sharp.     

FOREST MANAGEMENT ALTERNATIVES AND SONGBIRD BREEDING HABITAT ON THE CHEROKEE NATIONAL FOREST,TENNESSEE

Abstract: We used a 60-yr forest simulation of the Cherokee National Forest, Tennessee, USA, to model the effects of timber harvest and natural disturbance upon habitat availability for 6 songbird species: Acadian flycatcher (Epidonax virescens), blue-headed vireo (Vireo solitarius), chestnut-sided warbler (Dendroica pensylvanica), tufted titmouse (Parus bicolor), yellow-billed cuckoo (Coccyzus americanus), and yellow-throated warbler (Dendroica dominica). Forest simulations, based on expected harvest intensities and historic levels of natural disturbance, were used to update a stand inventory database at 10-yr intervals between 1993 and 2053. Habitat models for the 6 bird species were applied to the updated stand inventory and available habitat quantified for each decade. Late-successional species showed substantial increases in habitat availability over the 60-yr period at most harvest intensities, whereas habitat for early-successional species was stable or declined at most harvest intensities. Acadian flycatcher, yellow-throated warbler, and blue-headed vireo habitat increased by 200%, 213%, and 40%, respectively, whereas tufted titmouse habitat remained relatively constant at expected harvest levels. Chestnut-sided warbler habitat was stable at expected harvest levels but declined at lower harvest intensities, and yellow-billed cuckoo habitat declined by 37% at expected harvest levels. Natural disturbance had little effect on habitat availability for any bird species compared to the effects of timber harvests and increasing forest age. Our models suggest that anthropogenic disturbance, and lack thereof, can play a definitive role determining habitat availability and population viability for forest songbirds.     

PCR primers for polymorphic microsatellite loci in the facultatively polygynous plant‐ant Petalomyrmex phylax (Formicidae)

Fourteen microsatellite loci were isolated and their level of polymorphism characterized in two populations of the facultatively polygynous plant‐ant Petalomyrmex phylax (Formicinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from two to 15, and heterozygosity from 0.050 to 0.925. Cross‐species amplification of these loci was also tested in four plant‐ant species belonging to three other genera, Aphomomyrmex, Cladomyrma (both Formicinae) and Cataulacus (Myrmicinae).