The role of a regional bird collection in documenting avian diversity in a megadiverse country: The ornithological collection of the Natural History Museum of Universidad Industrial de Santander (UIS-AV), Colombia

Ornithological collections have long been of paramount importance in documenting the diversity and distribution of the avifauna of Colombia. Here, we summarize the taxonomic, temporal and spatial patterns of growth and coverage of the ornithological collection of the Natural History Museum of Universidad Industrial de Santander (UIS-AV) for the period 1970–2024. UIS-AV houses 3253 bird skins of 550 species, representing almost 30% of Colombia’s bird species, and 72% of the species historically collected in the Department of Santander. Most of the specimens in the collection were collected in two distinct decades: the 1970s and the 2010s. Our analyses of historical collecting efforts across 479 localities allowed us to identify regions in Santander department with high representation of specimens (e.g., swamps of the Magdalena River and around Bucaramanga), as well as poorly represented regions (e.g., Chicamocha River Canyon, highland Páramos, and the Carare-Opón lowlands). These analyses open avenues for conducting resurveys that address local changes in bird composition, and represent a roadmap for collecting efforts to fill populational and taxonomic gaps of Santander birds. UIS-AV complements historical records housed in foreign museums by adding specimen series from Santander localities originally collected by foreign collectors between the late nineteenth century and 1969. The modern methods of specimen preservation and curation now used at UIS-AV mean that 49% of the vouchers include tissue samples, as well as improved data quality for specimens. However, 83% of species housed at UIS-AV are represented by less than 10 specimens, precluding detailed biological studies, and calling for continued collecting to increase the representation of one of the richest avifaunas of northern South America.