- Discovery of the fossil bird Gastornis parisiensis.
- Thomas Campbell Eyton plans a large natural history museum at Eyton Hall.
- Purple-crowned fairywren discovered on Augustus Charles Gregory's northern Australian expedition.
- Birds described in 1855 include Tickell's brown hornbill, Tristan thrush, robust white-eye, sapphire quail-dove,
- William John Swainson and Louis Antoine François Baillon die.
- Howard Saunders begins bird studies in Brazil and Chile
- Gustav Radde joins the East Siberian Expedition of 1855, led by the astronomer Ludwig Schwarz.
- John Gould authors Descriptions of Eight New Species of Birds from South America. Proceedings of the Zoological Society of London 1855 Pt 23 no. 288: 67–70. online BHL
Ongoing events
- John Gould The birds of Australia; Supplement 1851–69. 1 vol. 81 plates; Artists: J. Gould and H. C. Richter; Lithographer: H. C. Richter
- John Gould The birds of Asia; 1850-83 7 vols. 530 plates, Artists: J. Gould, H. C. Richter, W. Hart and J. Wolf; Lithographers:H. C. Richter and W. Hart