{'fraction_non_alphanumeric': 0.0345679012345679, 'fraction_numerical': 0.0345679012345679, 'mean_word_length': 5.097744360902255, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Rediscovery of a lost type specimen of Alexander Wilson

ABSTRACT Only 2 of Alexander Wilson's (1766–1813) study skins are known to exist in modern collections with data confirming their provenance. Both are type specimens, preserved at the Academy of Natural Sciences of Drexel University (ANSP), and are among the most precious artifacts of American science. In 2018, I discovered a third Wilson type in the ANSP collection with a note from John Cassin (1813–1869) confirming its provenance. This paper describes the discovery and rediscovery of the type specimen of Wilson's “variety of the Black Hawk” (Falco niger), overlooked by ornithologists and historians for more than 150 yr. Nomenclature is unaffected because F. niger Wilson is a synonym of Buteo lagopus (Pontoppidan 1763), the Rough-legged Hawk.