About Me

35380213_10157882115149573_8522425016141217792_oWelcome to my website. I am a biologist and historian based at the Academy of Natural Sciences of Drexel University (ANSP, Philadelphia, Pennsylvania, USA), and the Editor of the Delaware Valley Ornithological Club (DVOC) and its historic journal Cassinia. I am a fifth-generation American, born in Pennsylvania and descended from German-Slovak immigrants. Most of the men in my family were soldiers, coal miners and mechanics, and the women were nurses and teachers. I am the first ornithologist in my family tree, but not the first birdwatcher.


Ornithology. I am fascinated by secretive species that inhabit dense forests and thickets, about which little is known on account of these circumstances. I wonder what they are up to, and how they got that way. After reading all of the literature that I can find, I collect and analyze original data to learn even more. The Nightingale-Thrushes (Aves: Turdidae: Catharus, Hylocichla) are my favorite study system. I have traveled to many spectacular places in pursuit of them, from Newfoundland and Labrador in Canada, to the Darién Gap in Colombia and Panama.

I use a variety of tools to reconstruct the evolutionary past and reveal the secret lives of birds. My interdisciplinary work combines specimen-based and field methods including phylogenetic analysis of DNA sequences, population genetics, morphometric analysis, video cameras, tracking devices, and audio playback experiments on marked and unmarked populations. I use these methods and technologies to reveal novel and interesting patterns of biodiversity, and to shed light on the evolutionary processes that produced them.


History of Science. My obsession with history and finding lost artifacts is probably a side effect of compulsively watching Indiana Jones movies as a kid. Many of the scientists whose lives I study were involved in bird research (including Catharus) during the 19th and 18th centuries. The primary question that drives this work — who knew what, when? — is fundamental to my work on avian taxonomy and systematics. Recently, I have (1) transcribed and annotated five unpublished letters of John J. Audubon with the original prospectus for The Birds of America (Halley 2015); (2) relocated Audubon’s type specimen of Western Meadowlark (Sturnella neglecta), which was misplaced 150+ years ago and presumed destroyed (Halley 2016); (3) exposed the composite nature of Alexander Wilson’s “Tawny Thrush” Turdus mustelinus (Halley 2018b); and (4) exposed major inconsistencies in Audubon’s famous banding experiment (Halley 2018a).

474652_10150647171339573_5094034_oMusic. I have been playing and writing songs since my childhood. My first instruments were piano and my voice, and somewhere along the way I learned to play the fretted instruments too (guitar, banjo, etc.). I have released several original albums and contributed as a guest musician on the projects of several artists. As a sound engineer and technical director, I have worked in small and medium-sized theatres (<350 people), and for a wide variety of live music and dance acts. As a musician, I have performed in many different venues, from living rooms to large arenas.




PhD Candidate, Drexel University
Department of Biodiversity, Earth & Environmental Science

Dean’s Fellow / McLean Fellow
Cumulative GPA:  4.0 / 4.0
Advised by Jason D. Weckstein

Graduate Research Associate
The Academy of Natural Sciences of Drexel University

MS, Natural Resources, Delaware State University
Graduated 2014, Cumulative GPA:  4.0 / 4.0
Advised by Christopher M. Heckscher


dsc_0239BA, Sociology, Pennsylvania State University
Graduated May 2004, Cumulative GPA:  3.4 / 4.0

No Degree, Music Recording Technology, Lebanon Valley College
Attended September 2000 – May 2001


Devon Preparatory School, Devon, PA
(Roman Catholic, Piarist Order)


I have been involved with scientific research projects in 9 countries. I am also an avid birder, and have contributed over 1000 checklists to the eBird database (Cornell University), including more than 475 within the city limits of Philadelphia, Pennsylvania.

Chiapas, Mexico, October 2018.

Anticipated expedition with Nathan H. Rice (Academy of Natural Sciences of Drexel University) and Dr. Luis Antonio Sánchez-González (Universidad Nacional Autónoma de México).

RACN, Nicaragua, March-April 2017.


General collecting expedition to two sites in the North Caribbean Coast Autonomous Region (RACN), in collaboration with the Academy of Natural Sciences of Drexel University and the Biodiversity Institute at University of Kansas (KU). The crew included Mark B. Robbins (KU Biodiversity Institute), Johnathan (Jack) P. Hruska (KU), and Therese Catanach (ANSP). We collected the first data-rich specimens from the humid rainforests of Parque Nacional Saslaya, as well as pine savanna and gallery forest sites near Alamikamba.

Pennsylvania, USA, May-June 2016.

MATTCo-creator and compiler of the Philadelphia Breeding Bird Census, the first systematic city-wide survey of breeding birds in the cradle of American ornithology. With a team of 75 (!) volunteers, we surveyed a linear distance of 262 km in the Philadelphia park system, counting 15,168 individuals of 101 species, and finding 231 nests of 42 species along the way. Breeding evidence was obtained for 71 species (70% of total). As the first attempt to comprehensively survey the breeding birds of Philadelphia, our census provides a baseline for future monitoring efforts. (Halley and Croasdale 2018).

Newfoundland and Labrador, Canada, June-July 2015.


Crew Leader of field expedition to collect genetic samples of Gray-cheeked Thrush (Catharus minimus), conduct avian point-count surveys, and vegetation surveys, in poorly-explored areas of the province. Research coordinated by the State University of New York, Memorial University of Newfoundland, and the New York State Museum. In addition to numerous sites around Newfoundland, we accessed many poorly-surveyed areas along the coast of Labrador as far north as Cartwright.

Delaware, USA, January 2011–October 2013.


Conducted the first intensive field-video-genetic study of the mating system of the Veery (Catharus fuscescens), at a long-term study site in the Mid-Atlantic Piedmont region. This study comprised my graduate thesis at Delaware State University (MS, Natural Resources), under the guidance of Dr. Christopher Heckscher, with whom I have now published several papers on Veery behavior. We were the first to document cooperative parental care and flexible polygynandry in the Veery (Halley and Heckscher 2012; 2013; Halley et al. 2016). Some nests were attended by multiple males, and others by males who were simultaneously feeding at multiple nests themselves, and both sexes had multiple sexual partners. We were also the first to demonstrate (with tracking devices) that Veeries undertake an intratropical migration in January–March, across the Amazon basin (Heckscher et al. 2015). That migration event was discovered by C. M. Heckscher, and it has now been shown to also occur in breeding populations in western North America (Hobson and Kardynal 2015).

Sapzurro, Colombia, October 2012.


Christopher Heckscher (Delaware State University) and I spent a week mist-netting and banding migratory and resident birds with Dr. Nicholas Bayly (Asociación SELVA, Bogota, Colombia), at his lowland rainforest field site in the Darién Gap. We captured multiple species of Catharus, including eastern and western races of the Veery (C. fuscescens, see photo), as well as numerous migrants and tropical resident species. It was spectacular to observe large migratory flocks of swallows and other passerines, careening along the forested ridges of the Caribbean coastline, arriving at last in South America after a long southward journey.

Karnataka, India, September 2009–January 2010.

trekkinggroupI conducted a study of rainforest frogs at an organic spice plantation in the Western Ghats, hosted by Drs. Anurag and Sujata Goel (WAPRED Research Foundation). My study resulted in range extensions for two poorly known Raorchestes species (see Halley and Goel 2012), and the first photographic series documenting the extent of their metachrosis (i.e., color-changing ability). I explored the jungle at night to collect frogs, and then kept them in a terrarium for a couple days at a time, while I photographed and observed them.

Nevada, USA, April 2006 – July 2008.

SATH_innest2For three consecutive breeding seasons, I assisted Dr. Aaron Holmes (Oregon State University) in a study of how songbird and small mammal communities in Sheldon National Wildlife Refuge respond to and recover from wildfire. This project spawned an independent study of biparental incubation and allofeeding by Brewer’s Sparrows (see Halley et al. 2015). I conducted point counts, searched for and monitored nests, deployed and operated small mammal trapping arrays, and ran time-lapse video camera systems at nests to collect behavioral data and identify predators.

Guàrico, Venezuela, September – November 2007.


I assisted Dr. Karl Berg (Cornell University) in studies of vocal learning and communication at nests of the Green-rumped Parrotlet (Forpus passerinus). The study was the first to document vocal learning in wild parrots. I netted, banded and bled adults and nestlings, conducted playback experiments, cross-fostered nests, and monitored behavior via digital video. See “How A Parrot Learns Its Name in the Wild” on YouTube. I also explored the llanos ecosystem on a daily basis, catching snakes, chasing capuchin monkeys, and trying to identify and learn something about everything that I encountered.

Hazeva, Israel, September 2005 – December 2005.

amotz_jaffaI assisted Drs. Amotz and Avishag Zahavi (Tel Aviv University) in their studies of Arabian Babblers (Turdoides squamiceps), and learned firsthand about the Handicap Principle and their model of (costly) signal evolution. Amotz taught me how to watch and anticipate bird behavior, as we tracked numerous babbler groups through the relatively open desert landscape. For many weeks, we discussed our daily observations over meals, while I asked him many questions about evolutionary theory. He took me to the Jerusalem Bird Observatory to volunteer for an afternoon, and paid for my enrollment in a banding (ringing) course in the Hula swamp. He was an important mentor to me during my earliest years as a biologist. Amotz passed away in May 2017 (obit).

Bocas Del Toro, Panama, February 2005 – June 2005.


I assisted Dr. Adam Stein (Syracuse University) in study of signal evolution in a hybrid zone where two kinds of collared manakins (Manacus spp.) meet and interbreed. We lived in remote jungle with a small indigenous community (Guaymí), and located leks in the secondary forest along the river’s edge. We mist-netted, banded, measured, and bled adult manakins, and monitored courtship displays via infra-red video and direct observation. This study was later featured on the front cover of Evolution (2006, 60: 1476–1485).


I have prepared over 160 data-rich specimens for the bird collection at the Academy of Natural Sciences of Drexel University (ANSP), including the neotype of the Veery Catharus fuscescens (Halley 2018). I have also located missing historical manuscripts, clarified the provenance of mislabeled or misplaced artifacts in large major collections, and made sporadic contributions to the entomology collections at ANSP and the National Museum of Natural History, Smithsonian Institution.

  • 10551612_10152644866494573_3552964080124307643_o2017–present — Graduate Research Associate, Dept. of Ornithology; Academy of Natural Sciences of Drexel University (ANSP: Philadelphia, PA)
  • 2016/17 — Curatorial Assistant, Dept. of Ornithology, ANSP (Philadelphia, PA)
  • 2010-11; 2017–18— Resident Caretaker, Wyck Historic House & Garden (Philadelphia, PA; manuscripts, rare artifacts)
  • American Museum of Natural History (New York, NY; ornithology)
  • Smithsonian National Museum of Natural History (Washington DC; ornithology)
  • Delaware Museum of Natural History (Wilmington, DE; ornithology)
  • American Philosophical Society Library (Philadelphia, PA; manuscripts)
  • Haverford College Library (Haverford, PA; manuscripts)
  • Wagner Free Institute of Science (Philadelphia, PA; ornithology)


See publications page or my profile on ResearchGate.


  • 2018 — Research Excellence Award — College of Arts and Sciences, Drexel University
  • 2017 — William L. McLean III Fellowship — $27,000 — Drexel University, Dept. of Biodiversity, Earth and Environmental Science
  • 2016 — Julian Potter Award — Delaware Valley Ornithological Club (DVOC)
  • 2016 — Teaching Excellence Award (nominee) — Drexel University
  • 2016 — Travel Award — $300 — Drexel University
  • 2015 — Elected ‘Fellow of the Delaware Valley Ornithological Club (DVOC)’
  • 2015 — Dean’s Fellowship —$10,000— Drexel University, College of Arts and Sciences
  • 2015 — Carbon Footprint Cup — 32nd Annual World Series of Birding, New Jersey Audubon
  • 2012 — Best Oral Presentation — Delaware State University, Graduate Research Symposium
  • 2009 — Carbon Footprint Cup — 26th Annual World Series of Birding, New Jersey Audubon


  • 2018 — Field Ornithology Lab (ENVS 553) — TA Instructor, Drexel University
  • 2016 — Field Ornithology (ENVS 580) — TA Instructor, Drexel University
  • 2015 — Evolution & Organismal Diversity (BIO 124) — TA Lab Instructor, Drexel University
  • 2015 — Cell Biology & Genetics (BIO 122) — TA Lab Instructor, Drexel University
  • 2015 — Ornithology (ENVS 606) — Guest Lecturer, University of Pennsylvania
  • 2013 — Advanced Wildlife Biology (NTRS 684) — Guest Lecturer, Delaware State University
  • 2012 — Tropical Ecology (AGRI 548) —Guest Lecturer, Delaware State University
  • 2012 — Ornithology (NTRS 312) — Guest Lecturer, Delaware State University


Wyck at the Dawn of American Science

  • 2017 — Annual Summer Lecture of the Wyck Association; Chestnut Hill Meeting House, Philadelphia, PA

Ethology and Systematics of the genus Catharus (Aves: Turdidae)

  • 2016 — Academy of Natural Sciences of Drexel University, Philadelphia, PA
  • 2016 — Drexel University, Department of Biodiversity Earth & Environmental Science (BEES), Graduate Research Seminar, Philadelphia, PA.

Thomas Jefferson: Birder in Chief

  • 2017 — Bucks County Birders; Peace Valley Nature Center, Doylestown, PA
  • 2016 — Delaware Valley Ornithological Club (DVOC), Philadelphia, PA — at the Academy of Natural Sciences of Drexel University
  • 2015 — American Philosophical Society Museum (in Philosophical Hall), Philadelphia, PA

Two centuries of climate change and arrival dates of migratory songbirds in the cradle of American ornithology: Philadelphia, PA (1802–2012)

  • 2016 – Pennypack Environmental Center, Philadelphia, PA.
  • 2014 – Cobbs Creek Community Environmental Education Center, Philadelphia, PA.

Kin structure and mating system of the Veery (Catharus fuscescens) in the Mid-Atlantic Piedmont

  • 2016 – North American Ornithological Conference (NAOC VI), Washington DC, USA.
  • 2016 – Birding Club of Delaware Valley, Broomall, PA.
  • 2016 – Evolutionary Biology Mixer — at Leidy Hall, University of Pennsylvania, Philadelphia, PA
  • 2015 – Washington Crossing Audubon Society, Pennington, NJ
  • 2015 – Eastern Bird Banding Association, Elk Neck State Park, MD
  • 2014 – Delaware Valley Ornithological Club (DVOC), Philadelphia, PA — at the Academy of Natural Sciences of Drexel University

Origins of American Ornithology- The View from Wyck

Multiple male feeders at nests of the Veery (Catharus fuscescens)

  • 2012 – North American Ornithological Conference (NAOC V), Vancouver, B.C., Canada. *Poster Presentation*
  • 2012 – Delaware Valley Ornithological Club (DVOC), Philadelphia, PA — at the Academy of Natural Sciences of Drexel University
  • 2012 – Graduate Research Symposium, Delaware State University. *Best Oral Presentation*
  • 2012 – Sussex Bird Club, Lewes, DE

Interhemispheric migratory movements of the Veery (Catharus fuscescens) revealed by light-level geolocator technology

  • 2012 – Q.E.D. Natural Science Symposium, Delaware State Univ., Dover, DE

The evolution of altruism: a personal journey

  • 2011 – Northeast Treatment-free Beekeeping Conference, Leominster, MA


  • Delaware Valley Ornithological Club (member since 2014)
  • American Ornithological Society (member since 2017)
  • Philadelphia Botanical Club (Programs committee, 2017–present)
  • Wilson Ornithological Society (member since 2011)
  • Delmarva Ornithological Society (member 2011–2013)
  • Phi Mu Alpha Sinfonia (inducted 2001)



Shaver’s Creek Raptor Center—Petersburg, Pennsylvania, August 2003 – December 2003. Provided primary care to 15 diurnal and nocturnal raptor species, 4 snake species, and 8 turtle species. Medicated ill birds. Fed resident animals daily. Cleaned and maintained enclosures. Handled and jessed birds for public education programs.

Macaw Landing Foundation—Portland, Oregon, August 2004 – December 2004. Assisted with care of over 90 captive macaws, representing >10 species. Cleaned and maintained enclosures. Assisted in medication of ill birds.


  • 2013 – Halley/McKeever/Palko — nominated for Best Folk/Americana Artist and Best Collaboration at the Homey Awards (93.7 WSTW); Wilmington, DE.
  • 2012 – “Let There Be Snow” (Halley/McKeever) nominated for Best Collaboration at the Homey Awards (93.7 WSTW); Wilmington, DE.
  • 2012 – Halley & McKeever, Delmarva Folk Hero Contest finalists; Delaware Friends of Folk.
  • 2008 – Live solo performance on the Folk Show w/ Gene Shay (88.5 WXPN Philadelphia)
  • 2006 – Solo piano performance at the Dji Sam Soe Jazz Festival, Sukabumi, Indonesia.
  • 2004 – Moab Arts Festival, Moab, UT.


  • Dave Holland Big Band
  • Zakir Hussain
  • Niladri Kumar
  • Miguel Zenón
  • Ned Rothenberg
  • Spoken Hand Percussion Orchestra
  • Amir ElSaffar
  • Lenny Seidman
  • Adam Rudolph

GUINEA PIG: Studies in which I was a subject.

  • 2006 — Sensory deprivation — I floated ~5 times in a sensory deprivation tank at the Restricted Environmental Stimuli Technique (R.E.S.T.) Flotation Laboratory, Penn State University, University Park, PA. My longest session was ~45 minutes in duration.
  • 2006 — Genetic factors relating to sexual behavior — I donated a drop of my blood and answered a detailed survey concerning my sexual habits for my brother Andrew C. Halley’s study examining covariance between DRD4 gene expression and sexual preferences, at Pennsylvania State University, University Park, PA.
  • 2013 — Raw oyster panel — I consumed 10 raw oysters in the Food Sciences Laboratory, Department of Human Ecology, Delaware State University, Dover, DE. (They were pretty gross!)
  • 2014 — Effects of tDCS stimulation on piano jazz Improvisation — I completed three sessions in which I improvised on piano, following a jazz lead sheet, while receiving transcranial direct-current stimulation (tDCS), at the Music & Entertainment Technology Lab, Department of Psychology, Drexel University, Philadelphia, PA, Apr–July 2014.




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