Here are the most important museums and institutions holding major ornithology collections, especially research collections of skins, skeletons, eggs, nests, fluid specimens, tissues, and type material.

Museum / Institution Location Why it matters
American Museum of Natural History — AMNH New York, USA One of the world’s great bird collections: nearly one million specimens, representing nearly 99% of avian species, with extensive skins, skeletons, eggs, nests, tissues, rare/extinct species, and many types.

Natural History Museum — NHM / Tring Tring & London, UK Among the largest and most comprehensive bird collections in the world, with over one million specimens and about 95% of bird species represented. Historically essential because of the Rothschild, Hartert, Sharpe, and British imperial-era collections.

Smithsonian National Museum of Natural History — USNM Washington, D.C., USA The Smithsonian’s Division of Birds holds over 600,000 specimens, about 85% of world bird species, and roughly 4,000 type specimens. Especially strong for North America, Pacific, Neotropics, and government-expedition material.
Field Museum of Natural History Chicago, USA One of the largest U.S. bird collections, with over 480,000 specimens, including about 600 holotypes, 70,000 skeletons, and major global holdings. Strong in Neotropical, African, Asian, and evolutionary-systematics work.

Museum of Comparative Zoology, Harvard — MCZ Cambridge, USA Nearly 400,000 ornithological specimens, representing nearly every genus and over 85% of bird families/species-level diversity depending on measure. Historically important through Louis Agassiz, William Brewster, Outram Bangs, and early American ornithology.

Muséum national d’Histoire naturelle — MNHN Paris, France One of Europe’s historically richest bird collections: about 130,000 study skins, 2,500 types, 30,000 mounted specimens, and specimens from about 75% of extant species. Especially important for early exploration, colonial-era material, and extinct/endangered species.

Naturalis Biodiversity Center Leiden, Netherlands About 400,000 bird specimens, with strong representation from the Netherlands, Indonesia, Suriname, and former Dutch colonial regions. Particularly important for Southeast Asian and historical type material.

Academy of Natural Sciences of Drexel University — ANSP Philadelphia, USA One of the 10 largest bird collections in the world, with over 215,000 study skins, more than 8,000 species, and extensive type, extinct/endangered, and Neotropical material. Historically tied to John Cassin and early American ornithology.

Yale Peabody Museum New Haven, USA More than 152,000 specimens, representing nearly 7,200 species and about 70% of global bird diversity. Especially significant for long historical series and Western Hemisphere material.

Burke Museum, University of Washington Seattle, USA Smaller than the giants but unusually modern and important: about 100,000 records, with strong tissue, spread-wing, skeleton, and Pacific Northwest / North Pacific material. It is known for one of the world’s largest spread-wing collections and a very large bird-tissue collection.

Cornell University Museum of Vertebrates — CUMV Ithaca, USA About 57,000 bird specimens, representing nearly all bird families. Not huge by global standards, but important because of Cornell’s broader ornithological ecosystem: Lab of Ornithology, Macaulay Library, eBird, and long-running avian research.

California Academy of Sciences San Francisco, USA Major West Coast natural history institution with important ornithology and mammalogy collections, strong Pacific, western North American, and expedition material. Scientifically active, though not as enormous as AMNH, NHM, or USNM.

A few others worth knowing, depending on region or specialty:

Los Angeles County Museum of Natural History, Carnegie Museum of Natural History, Royal Ontario Museum, Australian Museum, Museum für Naturkunde Berlin, Zoological Museum Copenhagen, South African Museum / Iziko, Bishop Museum in Honolulu, and Delaware Museum of Nature & Science all hold ornithological collections of real research value.