Ornithology最新文献

{"title":"Pacific Barrow's Goldeneye refine migratory phenology in response to overwintering temperatures and annual snowmelt","authors":"Jesse Kemp, W. Boyd, T. M. Forstner, D. Esler, T. Bowman, D. Douglas, Danica Hogan, M. Mcadie, Jonathan Thompson, Megan Willie, D. Green","doi":"10.1093/ornithology/ukad024","DOIUrl":"https://doi.org/10.1093/ornithology/ukad024","url":null,"abstract":"ABSTRACT Timing of seasonal bird migrations is broadly determined by internal biological clocks, which are synchronized by photoperiod, but individuals often refine their migratory timing decisions in response to external factors. Using 11 years of satellite telemetry data, we show that Pacific Barrow's Goldeneye (Bucephala islandica) at higher latitudes initiated spring and molt migrations later and fall migration earlier than individuals at lower latitudes. We further show that individuals refined migratory timing in response to interannual variation in environmental conditions. Individual Barrow's Goldeneye initiated spring migration earlier in years with warmer springs at their overwintering locations and concluded spring migration earlier in years with earlier annual snowmelt on their breeding grounds. Because individuals respond to conditions both where they initiate and where they conclude spring migration, our results suggest that Barrow's Goldeneye update their migratory decisions en route. For all 3 migrations in their annual cycle, birds delayed initiating migration if they had been captured and tagged prior to that migration. Birds that initiated migration late for their latitude were less likely to include a stopover and completed that migration faster, partially compensating for delayed departures. Our results are consistent with the hypothesis that Barrow's Goldeneye uses a combination of endogenous cues and environmental cues in migratory decision making. Sensitivity to environmental cues suggests that Barrow's Goldeneye may have behavioral plasticity that is adaptive when faced with ongoing climate change. LAY SUMMARY Migratory birds time their annual migrations to take advantage of temporal and spatial variation in resources, disease, and predation. Timing of these migrations is broadly determined by an internal biological clock set by day length, but individuals may refine when and how they migrate in response to environmental conditions. We used 11 years of satellite tracking data to investigate migratory cues in Barrow's Goldeneye, a species of sea duck. We found that birds used weather conditions as migratory cues, leaving their wintering grounds earlier in warmer springs and arriving on their breeding grounds earlier when the snow melted earlier in the year. Because individuals respond to conditions both where they start and where they end spring migration, our results suggest that Barrow's Goldeneye update their migratory decisions during migration. Barrow's Goldeneye's ability to respond to environmental cues suggests that they may be able to adapt to ongoing climate change. RÉSUMÉ Le calendrier des migrations saisonnières des oiseaux est largement déterminé par les horloges biologiques internes, qui sont synchronisées par la photopériode, mais les individus affinent souvent leurs décisions en matière de calendrier migratoire en réponse à des facteurs externes. En utilisant 11 années de données de télémétrie par satellite","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"173 1","pages":"1 - 13"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79552917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Robert William Nero, 1922–2023","authors":"M. Lein, S. Sealy, J. Duncan","doi":"10.1093/ornithology/ukad015","DOIUrl":"https://doi.org/10.1093/ornithology/ukad015","url":null,"abstract":"","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"18 1","pages":"1 - 3"},"PeriodicalIF":0.0,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73833699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phylogenomic analysis confirms the relationships among toucans, toucan-barbets, and New World barbets but reveals paraphyly of Selenidera toucanets and evidence for mitonuclear discordance","authors":"Emily N Ostrow, Therese A. Catanach, J. Bates, A. Aleixo, J. Weckstein","doi":"10.1093/ornithology/ukad022","DOIUrl":"https://doi.org/10.1093/ornithology/ukad022","url":null,"abstract":"ABSTRACT We reconstruct the species-level phylogenetic relationship among toucans, toucan-barbets, New World barbets using phylogenomic data to assess the monophyly and relationships at the family, generic, and specific levels. Our analyses confirmed (1) the monophyly of toucans (Aves: Ramphastidae), toucan-barbets (Aves: Semnornithidae), and New World barbets (Aves: Capitonidae) and that the toucan-barbets are sister to the toucans, an arrangement suggested, but poorly supported, in previously published phylogenies; (2) the paraphyly of lowland Selenidera toucanets with respect to Andigena mountain-toucans; and (3) evidence of some mitonuclear discordance, suggesting introgression or incomplete lineage sorting. For example, mitonuclear conflict in the phylogenetic placement of Ramphastos vitellinus subspecies suggests that Amazonian populations of Ramphastos vitellinus ariel may have introgressed mitogenomes derived from other Amazonian vitellinus taxa. To reconstruct the phylogenetic history of toucans, toucan-barbets, and New World barbets, we included all species-level taxa from the three families, with the addition of outgroups from the two major clades of Old World barbets (Megalaimidae and Lybiidae). We analyzed a combination of UCE sequences and whole mitochondrial genome sequences to reconstruct phylogenetic trees. LAY SUMMARY We analyzed relationships between all toucans, toucan-barbets, and New World barbets using both nuclear and mitochondrial DNA sequence data. We found highly supported relationships that showed that toucan-barbets are most closely related to toucans to the exclusion of New World barbets. Our results were consistent with previous research indicating that some Selenidera toucanets may be more closely related to Andigena mountain-toucans than they are to other Selenidera species. We found biologically relevant discordance between phylogenetic reconstructions using nuclear and mitochondrial data that give insight into potential historical introgression within Ramphastos. RESUMEN Reconstruimos la relación filogenética a nivel de especie entre tucanes, barbudos tucanes y barbudos del Nuevo Mundo utilizando datos filogenómicos para evaluar la monofilia y las relaciones a nivel de familia, género y especie. Nuestros análisis confirmaron (1) la monofilia de los tucanes (Aves: Ramphastidae), los barbudos tucanes (Aves: Semnornithidae) y los barbudos del Nuevo Mundo (Aves: Capitonidae), y que los barbudos tucanes son hermanos de los tucanes, un arreglo sugerido pero pobremente apoyado en filogenias publicadas anteriormente; (2) la parafilia de las tucanetas de las tierras bajas del género Selenidera en relación a los tucanes de montaña del género Andigena; y (3) la evidencia de alguna discordancia mitonuclear, lo que sugiere introgresión o clasificación incompleta de linajes. Por ejemplo, el conflicto mitonuclear en la ubicación filogenética de las subespecies de Ramphastos vitellinus sugiere que las poblaciones amazónicas de ","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"1 1","pages":"1 - 13"},"PeriodicalIF":0.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77901722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term, not short-term, temperatures predict timing of egg laying in European Starling","authors":"Kathryn M. Leonard, T. Williams","doi":"10.1093/ornithology/ukad020","DOIUrl":"https://doi.org/10.1093/ornithology/ukad020","url":null,"abstract":"ABSTRACT Temperature, particularly within ∼1 month of egg laying, is thought to be an important, short-term cue used by female birds to calibrate timing of breeding to local conditions. Here, we show that a relatively broad, long-term, temperature window (January 2 to April 4, 92 days; r2 = 0.73) best predicted timing of egg laying in European Starlings (Sturnus vulgaris). A “mid-winter” temperature window was also strongly correlated with laying date (r2 = 0.58), but we found no support for an influence of short-term temperatures immediately before egg laying. We assessed the relationship between ambient temperature and timing of egg laying using three complimentary approaches: (1) an “unconstrained,” exploratory analysis; (2) a traditional sliding window approach; and (3) specific, biologically informed temperature windows. Our results contrast with the widely held view that short-term, prebreeding temperatures best predict variation in laying because they allow birds to adjust timing of breeding to local conditions around the time of egg laying. This means that mechanisms that allow integration of long-term temperature information must exist in birds—perhaps most parsimoniously involving indirect effects of temperature on growth of the bird's ectothermic insect prey—even though these are currently poorly characterized. LAY SUMMARY Temperature is thought to be an important “supplemental cue” used by female birds to time breeding. It is widely assumed that late spring temperatures, within ∼1 month of egg laying, are most predictive of laying date, consistent with the idea that this fine-tunes timing of breeding to year-specific local conditions at the time of laying. Here, we show, in European Starlings, that a relatively broad temperature window (January 2 to April 4) best predicts laying date and that a long-term “mid-winter” temperature window (January 8 to February 22) was also strongly correlated with laying date. We found no evidence that short-term, immediate prelaying temperatures predict laying date. These results contrast markedly with the widely held view that immediate, prebreeding temperatures best predict variation in timing of laying. Birds must have mechanisms that allow integration of long-term temperature information even though these are currently poorly characterized. RESUMEN La temperatura, particularmente dentro de aproximadamente el primer mes antes de la puesta de huevos, se cree que es una señal importante a corto plazo que utilizan las aves hembra para ajustar el momento de la reproducción a las condiciones locales. Aquí mostramos que una ventana de temperatura relativamente amplia a largo plazo (del 2 de enero al 4 de abril, 92 días; r2 = 0.73) predijo mejor el momento de la puesta de huevos en Sturnus vulgaris. Una ventana de temperatura de “mediados del invierno” también estuvo fuertemente correlacionada con la fecha de puesta (r2 = 0.58), pero no encontramos apoyo para una influencia de las temperaturas a corto plaz","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"11 7 1","pages":"1 - 10"},"PeriodicalIF":0.0,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78297191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex, body size, and winter weather explain migration strategies in a partial migrant population of American Kestrels","authors":"Sadie Claire Ranck, Christina M. Garsvo, D. Schwartz, Linda M. Reynard, M. Kohn, J. Heath","doi":"10.1093/ornithology/ukad019","DOIUrl":"https://doi.org/10.1093/ornithology/ukad019","url":null,"abstract":"ABSTRACT Given increasing evidence that climate change affects the annual cycles of birds, it is important to understand the mechanisms underlying individual migration strategies and population-level patterns in partial migrants. In this study, we found that thermoregulation (body size and winter temperatures) was a key driver of American Kestrel (Falco sparverius) migration decisions. The annual proportion of migrants in the population, however, was not explained by winter weather and may be the result of differential survival. We measured stable hydrogen isotope values (δD) of talon tissues collected from 501 breeding and overwintering birds to distinguish migrant from resident kestrels in a partially migratory population of American Kestrels in southwestern Idaho in 2013–2021. We then evaluated drivers of migration decisions by assessing potential correlates of migration strategies, whether individuals switched migration strategies between years, and whether the proportion of migrants in the population changed over time or was correlated with winter weather. Male kestrels were 1.6 times more likely to migrate than females, and in colder than average winters, smaller birds of both sexes were more likely to migrate than larger birds. Only 27% of 26 recaptured individuals showed evidence of switching their migration strategies on an annual basis. There was no temporal trend in the proportion of migrants in the population, but proportions varied between years. Interestingly, there was no association between winter minimum temperature anomalies and annual migrant proportions in the population, suggesting that differential over-winter survival, or other stochastic processes, may play an important role in population composition. As winters continue to warm, fewer kestrels may migrate and more may remain resident on breeding grounds. However, it is unclear how changes in migration strategies might affect population-level patterns and resilience to climate change. LAY SUMMARY American Kestrels are the smallest falcon species in North America. Some individuals migrate South for the winter, while others stay on the breeding grounds year-round. It is unclear why some individuals migrate and others do not. We used the ratio of different mass variants of hydrogen in a small talon sample to determine whether a bird migrated or stayed on the breeding grounds for the winter. We found that smaller birds are more likely to migrate than larger birds, particularly in years with colder winter temperatures and that birds can change migration strategies from year to year. As winters continue to warm, fewer kestrels may migrate and more may remain resident on the breeding grounds. Potential changes in migration patterns may have important implications for monitoring kestrels at migration sites and for population resilience to climate change. RESUMEN Dada la creciente evidencia de que el cambio climático afecta los ciclos anuales de las aves, es importante comprender l","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"42 1","pages":"1 - 10"},"PeriodicalIF":0.0,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86019365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"100 years ago in the American Ornithologists' Union","authors":"Leesia C. Marshall","doi":"10.1093/ornithology/ukad012","DOIUrl":"https://doi.org/10.1093/ornithology/ukad012","url":null,"abstract":"","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"11 1","pages":"1 - 5"},"PeriodicalIF":0.0,"publicationDate":"2023-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78413749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lineage diversity in a widely distributed New World passerine bird, the House Wren","authors":"J. Klicka, Kevin L. Epperly, B. Smith, G. Spellman, Jaime A. Chaves, Patricia Escalante, C. Witt, Ricardo Canales-Del-Castillo, R. Zink","doi":"10.1093/ornithology/ukad018","DOIUrl":"https://doi.org/10.1093/ornithology/ukad018","url":null,"abstract":"ABSTRACT We explored the evolutionary radiation in the House Wren complex (Troglodytes aedon and allies), the New World's most widely distributed passerine species. The complex has been the source of ongoing taxonomic debate. To evaluate phenotypic variation in the House Wren complex, we collected 81,182 single-nucleotide polymorphisms (SNPs) from restriction site associated loci (RADseq) and mitochondrial DNA (mtDNA) from samples representing the taxonomic and geographic diversity of the complex. Both datasets reveal deep phylogeographic structuring, with several topological discrepancies. The trees highlight the evolutionary distinctiveness of eastern and western T. aedon, which were sister taxa in the SNP tree and paraphyletic on the mtDNA tree. The RADseq data reveal a distinct T. a. brunneicollis group, although STRUCTURE plots suggest admixture between western T. aedon and northern Mexican samples of T. a. brunneicollis. MtDNA data show a paraphyletic arrangement of T. a. musculus on the tree, whereas the SNP tree portrays them as monophyletic. Island taxa are distinct in both datasets, including T. a. beani (Isla Cozumel), which appears derived from T. a. musculus in eastern Mexico, and T. sissonii (Isla Socorro) and T. tanneri (Isla Clarión) although the 2 datasets disagree on their overall phylogenetic placement. Although we had only mtDNA data for T. a. martinicensis from the Lesser Antilles, we found at least 4 distinct and paraphyletic taxa from Trinidad, Granada, St. Vincent islands, and Dominica. The House Wren complex showed strong differentiation in mtDNA and RADseq datasets, with conflicting patterns likely arising from some combination of sex-biased dispersal, incomplete lineage sorting, or selection on mtDNA. The most glaring discrepancies between these 2 datasets, such as the paraphyly of eastern and western North American House Wrens in the mtDNA tree, present excellent opportunities for follow-up studies on evolutionary mechanisms that underpin phylogeographic patterns. LAY SUMMARY The House Wren (Troglodytes) complex consists of at least 5 distinct evolutionary groups distributed from Canada to southern South America. Morphological variation led taxonomists to name over 25 subspecies. We used mitochondrial DNA (mtDNA; 349 individuals) and a genome-wide survey of single nucleotide polymorphisms (RADseq; 184 individuals) to evaluate evolutionary patterns and determine their relationship to current taxonomy. The mtDNA data showed considerable differentiation, especially in island forms T. sissonii (Isla Socorro), T. a. beani (Isla Cozumel), and T. tanneri (Isla Clarión), and T. martinicensis, the latter of which includes several clades that were not monophyletic. MtDNA suggested that eastern and western samples of T. aedon were not monophyletic, whereas they were in the RADseq analyses; the cause of the discordance is unclear. We suggest that the RADseq data provide the most appropriate basis for classification and understandi","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"28 1","pages":"1 - 13"},"PeriodicalIF":0.0,"publicationDate":"2023-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81160233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Causes and consequences of nest-site fidelity in a tropical lekking bird: Win-stay-lose-shift tactics are unrelated to subsequent success, but site-faithful females nest earlier","authors":"Jenevieve E Norton, E. DuVal","doi":"10.1093/ornithology/ukad016","DOIUrl":"https://doi.org/10.1093/ornithology/ukad016","url":null,"abstract":"ABSTRACT Nest-site selection influences the survival of care-giving parents and their offspring, but search costs and site availability may limit site choices. Returning to previous nest sites may reduce costs and allow parents to better avoid local predators or access familiar resources. We investigated nest-site fidelity in the Lance-tailed Manakin (Chiroxiphia lanceolata), in which long-lived females raise offspring without male assistance, and found that site choices are responsive to past success but do not predict future outcomes. We compared georeferenced nest locations for the same females detected in consecutive years (245 comparisons for 138 females) and females nesting repeatedly within a year (137 comparisons for 97 females). Females were faithful to nesting sites in 13.9% of comparisons across years and 10.2% within years, and were more likely to nest again in the same site if their offspring fledged. When switching sites, females moved farther if their previous nest failed. Nest-site fidelity was unrelated to mate fidelity or female age. We then assessed whether site choice related to subsequent female survival, nest timing, or nest survival. Contrary to the hypothesis that win-stay-lose-shift tactics improve subsequent nesting outcomes, we found females were no more likely to fledge chicks or survive to a later year after they reused nest sites. However, across years, site-faithful females nested earlier on average than females that switched sites. Early nests were more likely to fledge chicks, and early-nesting females were more likely to renest when their first nesting effort was complete. Win-stay-lose-shift tactics may allow females to avoid areas where predation is likely, but new nest sites are not safer. Females that reuse nest sites benefit from early nest initiation, which both correlates with immediate success and creates potential for longer-term benefits of fidelity through increased opportunities to renest throughout the breeding season. LAY SUMMARY When females make repeated choices about where to build nests, they sometimes choose to nest in the same place, but it is unclear how this affects success. We used 19 years of information on the nest locations of individually banded female Lance-tailed Manakins to investigate why females renest at the same sites, and whether this behavior improves female survival or fledging success of the subsequent offspring. Females were more likely to reuse nest-sites if the prior nest was successful, but doing so did not improve offspring success or female survival. Females that reused nest locations laid eggs nearly 2 weeks earlier, on average, than females that switched sites, and chicks in early nests were more likely to fledge. Benefits of site fidelity come from indirect effects on nest timing, rather than from avoiding predators or securing successful sites for offspring. RESUMEN La selección del sitio de anidación influye en la supervivencia de los progenitores que brindan cuida","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"36 1","pages":"1 - 13"},"PeriodicalIF":0.0,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76248634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geographically consistent hybridization dynamics between the Black-crested and Tufted titmouse with evidence of hybrid zone expansion","authors":"G. Semenov, Claire M Curry, M. Patten, J. Weir, Scott A. Taylor","doi":"10.1093/ornithology/ukad014","DOIUrl":"https://doi.org/10.1093/ornithology/ukad014","url":null,"abstract":"ABSTRACT We studied hybridization between the Black-crested and Tufted titmouse across two geographically distinct transects that differ in the timing of secondary contact by hundreds to thousands of years. We found that hybridization patterns correspond to localized hybrid swarms and that the titmouse hybrid zone is likely slowly expanding over time, a product of short post-natal dispersal distances coupled with weak or absent selection against admixture. We show the southern part of the hybrid zone located in Texas is four times wider than the northern region of hybridization in Oklahoma, which is likely due to geographic differences in hybrid zone age. Despite differences in width, most individuals in both transects are advanced-generation hybrids and backcrosses, suggesting geographically consistent hybridization dynamics. We documented a strong correlation between genotypes and plumage index, suggesting that hybridization has not yet resulted in the decoupling of plumage and genome-wide ancestry as observed in some other avian hybrid zones. Although our results suggest the ongoing expansion of the hybrid zone, the rate of expansion appears to be slow, on the scale of tens of meters a year, and it will likely take hundreds of thousands to millions of years before homogenization of the parental populations. While we did not find support for partial reproductive isolation in the hybrid zone itself, there is the possibility that ecological or sexual selection limits introgression into allopatric regions. Broadly, the results of our study highlight the value of multiple, geographically distant, transects across a hybrid zone for assessing the evolutionary dynamics of hybridizing lineages. LAY SUMMARY We studied hybridization patterns between Black-crested and Tufted titmice in two areas of their contact zone that differ in the age of onset of hybridization by hundreds or thousands of years. We show that northern (younger) parts of the hybrid zone have a genetic transition four times narrower than the southern (older) region, which plausibly reflects the differences in the hybrid zone age or is a result of differences in the breadth of the ecotone between titmouse habitats in the north and south. Our results suggest that the Black-crested and Tufted titmouse hybrid zone might be in the process of slowly expanding following selectively neutral hybridization dynamics, although we cannot completely rule out a possible role of ecological or sexual selection in limiting gene flow outside of the hybrid zone. RESUMEN Estudiamos la hibridación entre Baeolophus atricristatus y B. bicolor a través de dos transectos geográficamente distintos que difieren en el momento del contacto secundario por cientos a miles de años. Encontramos que los patrones de hibridación corresponden a enjambres híbridos localizados y que la zona híbrida de Baeolophus probablemente se está expandiendo lentamente con el tiempo, producto de distancias cortas de dispersión postnatal, j","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"504 1","pages":"1 - 13"},"PeriodicalIF":0.0,"publicationDate":"2023-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77456722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leonard Alan Freed, 1947–2021","authors":"Patrick Hart","doi":"10.1093/ornithology/ukad011","DOIUrl":"https://doi.org/10.1093/ornithology/ukad011","url":null,"abstract":"","PeriodicalId":19617,"journal":{"name":"Ornithology","volume":"1 1","pages":"1 - 2"},"PeriodicalIF":0.0,"publicationDate":"2023-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90821022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}