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1. Avian Coloration Genetics: Recent Advances and Emerging Questions

   https://doi.org/10.1093/jhered/esab015  

   Price-Waldman, Rosalyn ; Stoddard, Mary Caswell ( May 2021 , Journal of Heredity)

   vonHoldt, Bridgett (Ed.)

   Abstract The colorful phenotypes of birds have long provided rich source material for evolutionary biologists. Avian plumage, beaks, skin, and eggs—which exhibit a stunning range of cryptic and conspicuous forms—inspired early work on adaptive coloration. More recently, avian color has fueled discoveries on the physiological, developmental, and—increasingly—genetic mechanisms responsible for phenotypic variation. The relative ease with which avian color traits can be quantified has made birds an attractive system for uncovering links between phenotype and genotype. Accordingly, the field of avian coloration genetics is burgeoning. In this review, we highlight recent advances and emerging questions associated with the genetic underpinnings of bird color. We start by describing breakthroughs related to 2 pigment classes: carotenoids that produce red, yellow, and orange in most birds and psittacofulvins that produce similar colors in parrots. We then discuss structural colors, which are produced by the interaction of light with nanoscale materials and greatly extend the plumage palette. Structural color genetics remain understudied—but this paradigm is changing. We next explore how colors that arise from interactions among pigmentary and structural mechanisms may be controlled by genes that are co-expressed or co-regulated. We also identify opportunities to investigate genes mediating within-feather micropatterning and the coloration of bare parts and eggs. We conclude by spotlighting 2 research areas—mechanistic links between color vision and color production, and speciation—that have been invigorated by genetic insights, a trend likely to continue as new genomic approaches are applied to non-model species. 

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2. Convergent niche shifts of endangered parrots (genus Amazona ) during successful establishment in urban southern California

   https://doi.org/10.1111/ddi.13817  

   Ramirez, Brenda R. ; Freeland, Rowdy J. ; Muhlheim, Allison ; Zellmer, Amanda J. ; DeRaad, Devon A. ; Kirsch, Eliza J. ; Mutchler, Marquette J. ; Secor, Maeve B. ; Reckling, Kelsey R. ; Schedl, Margaret E. ; et al ( February 2024 , Diversity and Distributions)

   Introduced species offer insight on whether and how organisms can shift their ecological niches during translocation. The genusAmazonaoffers a clear test case, where sister species Red‐crowned (A. viridigenalis) and Lilac‐crowned Parrots (A. finschi) have established breeding populations in southern California following introduction via the pet trade from Mexico where they do not coexist. After establishment in the 1980s, introduced population sizes have increased, with mixed species flocks found throughout urban Los Angeles. Here, we investigate the differences between the environmental conditions of the native and introduced ranges of these now co‐occurring species.

   Southern California and Mexico.

   Using environmental data on climate and habitat from their native and introduced ranges, we tested whether Red‐crowned and Lilac‐crowned Parrots have divergent realized niches between their native ranges, and whether each species has significantly shifted its realized niche to inhabit urban southern California. We also analysed data from Texas and Florida introductions of Red‐crowned Parrots for comparative analysis.

   There are significant differences in the native‐range niches of both parrot species, but a convergence into a novel, shared environmental niche into urban southern California, characterized by colder temperatures, less tree cover and lower rainfall. Texas and Florida Red‐crowned Parrots also show evidence for niche shifts with varying levels of niche conservatism through the establishment of somewhat different realized niches.

   Despite significant niche shifts, introduced parrots are thriving, suggesting a broad fundamental niche and an ability to exploit urban resources. Unique niche shifts in different U.S. introductions indicate thatAmazonaparrots can adapt to diverse environmental conditions, with cities offering a resource niche and the timing of introduction playing a crucial role. Cities can potentially serve as refugia for threatened parrot species, but the risk of hybridization between species emphasizes the need for ongoing monitoring and genetic investigations.

    

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3. Changes in parrot diversity after human arrival to the Caribbean

   https://doi.org/10.1073/pnas.2301128120  

   Oswald, Jessica A. ; Smith, Brian Tilston ; Allen, Julie M. ; Guralnick, Robert P. ; Steadman, David W. ; LeFebvre, Michelle J. ( October 2023 , Proceedings of the National Academy of Sciences)

   Humans did not arrive on most of the world’s islands until relatively recently, making islands favorable places for disentangling the timing and magnitude of natural and anthropogenic impacts on species diversity and distributions. Here, we focus onAmazonaparrots in the Caribbean, which have close relationships with humans (e.g., as pets as well as sources of meat and colorful feathers). Caribbean parrots also have substantial fossil and archaeological records that span the Holocene. We leverage this exemplary record to showcase how combining ancient and modern DNA, along with radiometric dating, can shed light on diversification and extinction dynamics and answer long-standing questions about the magnitude of human impacts in the region. Our results reveal a striking loss of parrot diversity, much of which took place during human occupation of the islands. The most widespread species, the Cuban Parrot, exhibits interisland divergences throughout the Pleistocene. Within this radiation, we identified an extinct, genetically distinct lineage that survived on the Turks and Caicos until Indigenous human settlement of the islands. We also found that the narrowly distributed Hispaniolan Parrot had a natural range that once included The Bahamas; it thus became “endemic” to Hispaniola during the late Holocene. The Hispaniolan Parrot also likely was introduced by Indigenous people to Grand Turk and Montserrat, two islands where it is now also extirpated. Our research demonstrates that genetic information spanning paleontological, archaeological, and modern contexts is essential to understand the role of humans in altering the diversity and distribution of biota.

    

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4. Review of Conservation Challenges and Possible Solutions for Grassland Birds of the North American Great Plains

   https://doi.org/10.1016/j.rama.2023.07.002  

   Bernath-Plaisted, Jacy S. ; Correll, Maureen D. ; Somershoe, Scott G. ; Dwyer, Angela M. ; Bankert, Andy ; Beh, Adam ; Berlanga, Humberto ; Boyle, W. Alice ; Cruz-Romo, J. Lizardo ; George, T. Luke ; et al ( September 2023 , Rangeland Ecology & Management)

   North America’s grassland birds remain in crisis despite decades of conservation effort s. This review pro- vides an overview of factors contributing to these declines, as well as strategies and resources available to a diversity of stakeholders to help conserve grassland bird communities with an emphasis on the Great Plains—a grassland region of global ecological significance and a habitat stronghold for grassland birds. Grassland bird declines are driven by historical and continuing threats across the full annual cycle including grassland habitat loss, agriculture intensification, woody encroachment, and disruption of fire and grazing regimes. More recently, energy development activities, the use of neonicotinoid pesticides, and anthropogenic climate change have emerged as additional threats. While threats to grassland birds are numerous and often synergistic, possibilities for conservation are also diverse and multifaceted. Land set-aside programs, incentives and voluntary practices for producers, improved environmental manage- ment by energy and utility companies, and policy and regulation can all contribute to the conservation of these unique species. We suggest that future grassland bird research should focus on poorly studied aspects of the annual cycle, such as overwinter survival and habitat use, and the migratory period, which remains completely unexplored for many species. Filling these knowledge gaps may facilitate more so- phisticated population modeling that can identify limiting factors and more effectively guide investment in conservation. 

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5. Life on the edge: Hawaiian model for coral evolution

   https://doi.org/10.1002/lno.12181  

   Bhattacharya, Debashish ; Stephens, Timothy G. ; Tinoco, Amanda I. ; Richmond, Robert H. ; Cleves, Phillip A. ( July 2022 , Limnology and Oceanography)

   Degradation and loss of coral reefs due to climate change and other anthropogenic stressors has fueled genomics, proteomics, and genetics research to investigate coral stress response pathways and to identify resilient species, genotypes, and populations to restore these biodiverse ecosystems. Much of the research and conservation effort has understandably focused on the most taxonomically rich regions, such as the Great Barrier Reef in Australia and the Coral Triangle in the western Pacific. These ecosystems are analogous to tropical rainforests that also house enormous biodiversity and complex biotic interactions among different trophic levels. An alternative model ecosystem for studying coral reef biology is the relatively species poor but abundant coral reefs in the Hawaiian Archipelago that exist at the northern edge of the Indo‐Pacific coral distribution. The Hawaiian Islands are the world's most isolated archipelago, geographically isolated from other Pacific reef systems. This region houses about 80 species of scleractinian corals in three dominant genera (Porites,Montipora, andPocillopora). Here we briefly review knowledge about the Hawaiian coral fauna with a focus on our model species, the rice coralMontipora capitata. We suggest that this simpler, relatively isolated reef system provides an ideal platform for advancing coral biology and conservation using multi‐omics and genetic tools.

    

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