Research program

My research program aims to understand the evolutionary processes responsible for the formation and maintenance of biological diversity. Specifically, I study the genomic mechanisms that contribute to speciation and phenotypic differentiation at microevolutionary and macroevolutionary scales in birds. My strong background with field and collections-based ornithology is central to my research. My research questions and datasets arise from collecting specimens in the field, quantifying phenotypic variation from research specimens, and collecting genomic datasets from vouchered specimens in the laboratory. I use computational methods in all aspects of my research, including genomic and phenotypic characterization of hybrid zones, genomic association studies, demographic modeling, comparative phylogeography, conservation genetics, spatial ecology and phylogenomics. Check out some of my projects:


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2021  | Del-Rio et al. Displaced clines in an avian hybrid zone (Thamnophilidae:Rhegmatorhina) within an Amazonian interfluve. Evolution 

2020  |  Feng, Del-Rio et al. Dense sampling of bird diversity increases power of comparative genomics. Nature. 587, p. 252-257

Genomics of speciation in an Amazonian hybrid zone

In my PhD research I study the hybrid zone between two Amazonian birds, the White-breasted Antbird (Rhegmatorhina hoffmannsi) and the Harlequin Antbird (R. berlepschi). These birds are obligate army-ant followers. As Army-ants send out huge raiding parties that flush roaches, spiders, and other arthropods from the leaf litter, Rhegmatorhina forages above the ant swarms capturing the exposed large arthropods and even small vertebrates. Besides being super cool birds, the hybridizing Rhegmatorhina provide a unique natural system for the study of how new species arise and are maintained. Using morphological data, target capture, whole genomes and GWAS, I try to understand the genetic structure of this hybrid zone, its demographic dynamics, and which are the reproductive isolating mechanisms preventing these two species from fusing into a single one. In the future, I would like to advance the genomic association results of this project to functional tests in cell cultures. 

Comparison of genomic landscape of Rhegmatorhina hoffmannsi with different

mitochondrial haplotypes. Rhegmatorhina illustrations by Glaucia Del-Rio.

Sampling of our comparative phytogeography work exploring genetic differentiation in 3 species complexes. Points on both banks of the Juruá River indicate localities sampled along the Emilie Snethlage Expedition. Illustrations by Marky Mutchler: Willisornis, Epinecrophylla, and Myrmoborus.

2021  |    Del-Rio et al. Birds of the Juruá River: extensive várzea forest as a barrier to terra firme birds.  Journal of Ornithology. 162, p. 565–577

Amazonian rivers as barriers for birds

In 2019, I decided to pay a tribute to Emilie Snethlage, by making an all-women expedition to the Amazon Forest. We chose to sample the Juruá River area, because that was a frontier in Amazonian ornithology and the only river never visited by Emilie Snethlage. In a team with 9 women biologists, we gathered an extensive collection for the area and came to the realization that a few species pairs would replace each other on opposite river banks. This result was unexpected, because the Juruá is quite narrow and super dynamic. Our preliminary data suggest that the wide seasonally flooded forest of the Juruá plays an important role on preventing that some birds, from the forest interior, would cross the river. Today, Marky Mutchler and I are working together on gathering  genomic data (ultra conserved elements) to better understand population genetics and phylogeographic patterns of four species complexes from the Juruá region. The Emilie Snethlage Expedition would not be possible without the support of our amazing donors! Thank you very much!

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2017  |    Del-Rio et al. Plant Invasion: another threat to the São Paulo Marsh Antwren (Formicivora paludicola), a species on the verge of extinction. PloSOne. 12(12), p. e0189465

2016  |    Del-Rio et al. Remarks on the Natural History of São Paulo Marsh Antwren (Formicivora paludicola). Wilson Journal of Ornithology. 128 (2), p. 445-448

2015  |    Del-Rio et al. A multiscale approach indicates a severe reduction in Atlantic Forest wetlands and highlights that São Paulo Marsh Antwren is on the brink of extinction. PloSOne. 10, p. e0121315

2015  |    De Camargo, Del-Rio et al. Marshes as mountain tops: genetic analyses of the Critically Endangered São Paulo Marsh Antwren. PloSOne. 10(10), p. e0140145

2015  |    De Camargo, Del-Rio et al. Novel and cross-amplified microsatellite loci for the critically endangered São Paulo Marsh Antwren Formicivora paludicolaConservation Genetics Resource. 7, p. 129

Ecology and conservation of a bird on the verge of extinction

During my master's, I studied the spatial ecology, natural history and distribution of the São Paulo Marsh Antwren (Formicivora paludicola). This bird inhabits marshes around the metropolitan region of São Paulo City and it is Critically Endangered because of the growing urban areas, sand mining and farming. During three years, many volunteers helped me to band and monitor São Paulo Marsh Antwren individuals living in three different areas. Besides all the intense field work, this project gave me a unique opportunity to develop abilities with ecological niche modeling, occupancy models, home range, and analysis of habitat selection. A collaboration with Crisley Camargo, also generated data on population genetics. Today, I am happy that the results of my master's project provided information for the creation of the first protected area dedicated to the conservation of the São Paulo Marsh Antwren.


Home range and habitat use of 15 of the Formicivora paludicola individuals I banded during my masters. Graph shows that the probability of occurrence of F. paludicola is very low in areas with large density of Ginger Lily, an exotic invasive plant.

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Illustrations by Glaucia Del-Rio: Piculus flavigula erythopis and Piculus flavigula magnus

2014  |    Rego, Del-Rio et al. A taxonomic review of Picumnus exilis (Aves: Picidae) reveals an underestimation of Piculet species diversity in South America. Journal of Ornithology. 155, p. 853-867

2013  |    Del-Rio et al. A taxonomic review of the Golden-green Woodpecker, Piculus chrysochloros (Aves: Picidae) reveals the existence of six valid taxa. Zootaxa. 3626, p. 531-542

Systematics of Neotropical birds

For my undergraduate thesis, I worked with taxonomy of the Golden-green Woodpecker (Piculus chrysochloros). After analyzing vocalization and morphological characters of specimens in collections from South America, the United States and Europe, I elevated some of the subspecies in the complex to the specific status. Such changes were important for the conservation of two threatened species, one from the Atlantic Forest, and the other from Eastern Amazon. As a side project, I also worked on the systematics of the Yellow-throated Woodpecker (Piculus flavigula) and I collaborated with Marco Rego on a taxonomic revision of the Golden-spangled Piculet (Picumnus exilis) complex. It was an amazing immersion in the world of woodpeckers, one of my favorite group of birds! These projects also gave me the chance to spend a lot of time in museum collections, the best place to learn about birds in detail. During my career, I also worked on systematics and taxonomy of other species complexes, including Caryothraustes canadensins, Vireolanius leucotis, Myrmoborus myotherinus and Hylophylax naevius.

Number of bird specimens housed in museum collections. Warm colors indicate areas with more specimens, and cool colors indicate areas poorly sampled (less than 25 specimens)

Amazonian suture zones

Since 2015, I am a collaborator (second author) in a project in which we are mapping the distribution of all Amazonian bird taxa, including species and subspecies. 80% of our ~620,000 point localities were obtained from museum specimens housed in 30 museum collections in Europe, South and North America. We are using this huge dataset to assess the: (1) locations of bird suture zones across the Amazonian landscape; (2) relative importance of geographic barriers for birds; (3) gaps in the ornithological knowledge and sampling effort; (4) composition of areas of endemism; (5) habitat loss of Amazonian birds in face of deforestation and climate change. In 2021, our talk on Amazonian suture zones was awarded with the AOS (American Ornithological Society A. Brazier Howell) Award given for the best presentation on any topic in ornithology! Stay tuned for our upcoming publications!

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