scholarly journals Structure and Dynamics of The Hybrid Zone Between Black-Capped Chickadee (Poecile Atricapillus) and Carolina Chickadee (P. Carolinensis) in Southeastern Pennsylvania

The Auk ◽  
2007 ◽  
Vol 124 (2) ◽  
pp. 463-478 ◽  
Author(s):  
Matthew W. Reudink ◽  
Stephen G. Mech ◽  
Sean P. Mullen ◽  
Robert L. Curry
Keyword(s):  
Hybrid Zone ◽  
Selective Advantage ◽  
Genetic Introgression ◽  
Poecile Atricapillus ◽  
Large Numbers ◽  
Starting Point ◽  
Carolina Chickadee ◽  
Northern Edge ◽  
Historical Accounts ◽  
Carolina Chickadees

AbstractAnalysis of the structure and stability of a hybrid zone can serve as a starting point for examining mechanisms that influence spatial and evolutionary relationships between species. Recent studies of the hybrid zone between Black-capped Chickadee (Poecile atricapillus) and Carolina Chickadee (P. carolinensis) have suggested that genetic introgression is limited to a narrow zone, while also reinforcing the conclusion that the line of contact between these parapatrically distributed species is now shifting northward. We investigated the structure, position, and recent movement of the chickadee hybrid zone in southeastern Pennsylvania. Using selectively neutral microsatellite DNA markers, along with mitochondrial DNA haplotypes, we documented large differences in genetic composition among three populations ≤65 km apart where we sampled large numbers of breeding residents during 1998–2003. Genetic results indicate that the three sites support a population of Carolina Chickadees (Great Marsh), a population in which most individuals exhibit evidence of hybridization (Nolde Forest), and a population comprising mostly Black-capped Chickadees but with evidence of hybridization now taking place (Hawk Mountain). The patterns within the Nolde Forest population suggest that selection against hybrids may not be as strong as has been concluded from studies in other parts of the chickadee hybrid zone. Comparison of mitochondrial and nuclear genotypes between samples collected ≈15 years apart suggest that the northern edge of the hybrid zone shifted by ≈20 km over this interval, with hybridization now occurring as far north as the Kittatinny Ridge and beyond, where only Black-capped Chickadee genotypes were previously detectable. Our data and historical accounts suggest that the hybrid zone, now ≈50 km wide, may have become wider while also shifting northward. These results support the hypothesis that Carolina Chickadees enjoy a selective advantage during hybridization with Black-capped Chickadees, but both the proximate mechanisms and ultimate causes remain to be investigated.Structure et dynamique de la zone d'hybridation entre Poecile atricapillus et P. carolinensis dans le sud-est de la Pennsylvanie

scholarly journals Reproductive Success Across The Black-Capped Chickadee (Poecile Atricapillus) and Carolina Chickadee (P. Carolinensis) Hybrid Zone in Ohio

The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 759-772 ◽  
Author(s):  
C. L. Bronson ◽  
Thomas C. Grubb ◽  
Gene D. Sattler ◽  
Michael J. Braun
Keyword(s):  
Reproductive Success ◽  
Hybrid Zone ◽  
Past Century ◽  
Genetic Introgression ◽  
Genetic Composition ◽  
Poecile Atricapillus ◽  
Relative Paucity ◽  
Carolina Chickadee ◽  
The Face ◽  
East West

AbstractBlack-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (P. carolinensis) hybridize in an east-west band from New Jersey to Kansas. Within the past century, the Ohio portion of this hybrid zone and the Carolina Chickadee range to the south have been moving northward, whereas the Black-capped Chickadee range has retracted. In Ohio, we characterized the genetic composition of the hybrid zone using five diagnostic molecular loci. Although there was no evidence of assortative mating in the center of the hybrid zone, we found a relative paucity of genetically intermediate breeding females as compared with breeding males. That suggests viability selection against female hybrids, in line with Haldane’s rule. On the basis of reproductive variables (number of nestlings, reproductive success), we found a decrease in productivity of breeding pairs in the hybrid zone that is significantly and positively related to their probability of producing homozygous offspring at each autosomal or sex-linked locus. We also found that the decrease in productivity was significantly and positively related to the genetic composition of the male of the pair (i.e. pure male chickadees more productive). These data strongly suggest that hybrids are at a selective disadvantage. Because the zone of reduced reproductive success was considerably narrower than the zone of introgression, our results demonstrate that genetic introgression is occurring in the face of substantial selection against hybrids.Éxito Reproductivo a través de la Zona de Hibridación de Poecile atricapillus y P. carolinensis en Ohio

Note types and coding in parid vocalizations. III: The chick-a-dee call of the Carolina chickadee (Poecile carolinensis)

2005 ◽  
Vol 83 (6) ◽  
pp. 820-833 ◽  
Author(s):  
Laurie L Bloomfield ◽  
Leslie S Phillmore ◽  
Ronald G Weisman ◽  
Christopher B Sturdy
Keyword(s):  
Acoustic Communication ◽  
Comparative Studies ◽  
Individual Recognition ◽  
Poecile Atricapillus ◽  
Poecile Carolinensis ◽  
Carolina Chickadee ◽  
Carolina Chickadees

Species of the genus Poecile Kaup, 1829 (the chickadees) are well suited to comparative studies of acoustic communication because their songs and calls occur in similar contexts and are acoustically similar. Here we provide careful, reliable descriptions and spectrographic exemplars for seven note types observed in the chick-a-dee calls of the Carolina chickadee, Poecile carolinensis (Audubon, 1834). The note types include A, C, and D notes similar to those found in the chick-a-dee calls of the black-capped chickadee, Poecile atricapillus (L., 1766), a complex of three B-note subtypes (B1, B2, and B3) and a rare note type previously identified as high-tee-chick. In common with black-capped chickadees, the organization of note types in Carolina chickadees follows a stringent syntax; the position of note types within a call is fixed. In contrast with black-capped chickadees, the chick-a-dee call syntax of the Carolina chickadee includes a B-note complex composed of three acoustically distinct subtypes of B notes, and follows a strict syntax: A→(B1→B2→B3)→C→D. Analysis of call variability suggests that the B-note complex (in particular, the most commonly sung note, B2) and the D note may provide reliable cues for species and individual recognition.

scholarly journals An Assessment of Song Admixture as an Indicator of Hybridization in Black-Capped Chickadees (Poecile Atricapillus) and Carolina Chickadees (P. Carolinensis)

The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 926-944 ◽  
Author(s):  
Gene D. Sattler ◽  
Patricia Sawaya ◽  
Michael J. Braun
Keyword(s):  
Contact Zone ◽  
Ecological Factors ◽  
Principal Component ◽  
Song Type ◽  
Genetic Introgression ◽  
Genetic Composition ◽  
Poecile Atricapillus ◽  
Quantitative Analyses ◽  
Different Levels ◽  
Carolina Chickadees

AbstractVocal admixture often occurs where differentiated populations or species of birds meet. This may entail song sympatry, bilingually singing birds, and songs with intermediate or atypical characteristics. Different levels of vocal admixture at the range interface between Black-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (P. carolinensis) have been interpreted as indicating that hybridization is frequent at some locations but not others. However, song ontogeny in these birds has a strong nongenetic component, so that inferences regarding hybridization based on vocal admixture require confirmation. We used diagnostic genetic markers and quantitative analyses of song to characterize population samples along two transects of the chickadee contact zone in the Appalachian Mountains. More than 50% of individuals at the range interface were of hybrid ancestry, yet only 20% were observed to be bilingual or to sing atypical songs. Principal component analysis revealed minimal song intermediacy. This result contrasts with an earlier analysis of the hybrid zone in Missouri that found considerable song intermediacy. Re-analysis of the Missouri data confirmed this difference. Correlation between an individual’s genetic composition and its song type was weak in Appalachian hybrid populations, and genetic introgression in both forms extended far beyond the limits of vocal admixture. Therefore, song is not a reliable indicator of levels of hybridization or genetic introgression at this contact zone. Varying ecological factors may play a role in producing variable levels of song admixture in different regions of the range interface.Una Evaluación de la Mixtura de Cantos como Indicador de Hibridación en Poecile atricapillus y P. carolinensis

scholarly journals Rewriting a History of Open Universities

2019 ◽  
Vol 20 (4) ◽  
Author(s):  
Kyungmee Lee
Keyword(s):  
Qualitative Study ◽  
Technological Innovation ◽  
Teaching Practice ◽  
Methodological Approach ◽  
Autobiographical Narratives ◽  
The Past ◽  
Starting Point ◽  
History Of ◽  
Historical Accounts ◽  
Distance Educators

This article reports eight distance teachers’ stories about teaching at two open universities over the past two decades with a focus on their perceptions and feelings about the changes in their teaching practice. This qualitative study employed a methodological approach called the autoethnographic interview, aiming to document more realistic histories of the open universities and to imagine a better future for those universities. As a result, the paper presents autobiographical narratives of distance teachers that dissent from the general historical accounts of open universities. These narratives are categorized into three interrelated themes: a) openness: excessive openness and a lost sense of mission; b) technological innovation: moving online and long-lasting resistance, and c) teaching: transactional interactions and feelings of loneliness. The paper then presents a discussion of useful implications for open universities, which can serve as a starting point for more meaningful discussions among distance educators in a time of change.

The genesis of international mass migration

2018 ◽  
Author(s):  
Eric Richards
Keyword(s):  
North America ◽  
Structural Changes ◽  
British Isles ◽  
Scottish Highlands ◽  
Isle Of Man ◽  
Mass Migration ◽  
Large Numbers ◽  
Starting Point ◽  
The Common ◽  
Over Time

Very large numbers of people began to depart the British Isles for the New Worlds after about 1770. This was a pioneering movement, a rehearsal for modern international migration. This book contends that emigration history is not seamless, that it contains large shifts over time and place, and that the modern scale and velocity of mobility have very particular historical roots. The Isle of Man is an ideal starting point in the quest for the engines and mechanisms of emigration, and a particular version of the widespread surge in British emigration in the 1820s. West Sussex was much closer to the centres of the expansionary economy in the new age. North America was the earliest and the greatest theatre of oceanic emigration in which the methods of mass migration were pioneered. Landlocked Shropshire experienced some of the earliest phases of British industrialisation, notably in the Ironbridge/Coalbrookdale district, deep inland on the River Severn. The turmoil in the agrarian and demographic foundations of life reached across the British archipelago. In West Cork and North Tipperary, there was clear evidence of the great structural changes that shook the foundations of these rural societies. The book also discusses the sequences and effects of migration in Wales, Swaledale, Cornwall, Kent, London, and Scottish Highlands. It also deals with Ireland’s place in the more generic context of the origins of migration from the British Isles. The common historical understanding is that the pre-industrial population of the British Isles had been held back by Malthusian checks.

Using historical accounts to assess the occurrence and distribution of small cetaceans in a poorly known area

2010 ◽  
Vol 90 (8) ◽  
pp. 1583-1588 ◽  
Author(s):  
Cristina Brito ◽  
Nina Vieira
Keyword(s):  
Historical Data ◽  
Historical Science ◽  
13Th Century ◽  
Historical Sources ◽  
Baleen Whales ◽  
Delphinus Delphis ◽  
Large Numbers ◽  
Alternative Sources ◽  
Historical Accounts ◽  
Common Dolphins

Historical science may play an important role in helping understanding and shaping the future of the world's oceans and to comprehend present day effects and conditions. Regarding cetaceans, historical accounts may be extremely useful to add new data to their occurrence and distribution in poorly studied regions. In Portugal, historical sources indicate that toninhas (possibly common dolphins Delphinus delphis) were observed since the 13th Century and were captured in large numbers during the late 19th and 20th Centuries. Historical occurrences given by naturalists and scientific surveys conducted by biologists indicate their regular presence with particular preference for certain areas. Also, recent observations of opportunity resulted in the same kind of accounts. Between 1976 and 1978, a study on captured cetaceans along the Portuguese shore found at fish markets was conducted and resulted in a total count of 45 cetaceans. Most captures were of small cetaceans (87% common dolphins), even though four baleen whales were registered. These cetacean captures were part of a local non-industrial fishery, as they were not the main target, but rather opportunistic catches or even by-catches of other fisheries. Delphinids were not protected by law at the time and were caught with hand harpoons or accidentally drowned in fish nets, sometimes sold at major fish markets such as Sesimbra, Peniche and Póvoa de Varzim. In geographical areas where recent cetacean sightings are rare and information is sparse, such as Portugal, it becomes important to take advantage of alternative sources of data. Our contribution towards the compilation of relevant historical and ‘forgotten’ science such as old natural observations, whaling data and observations of opportunity stresses the relevance of using historical data to access past occurrence and distribution of cetaceans.

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