A unique reprint of M. A. Carriker's classic article, ‘An annotated list of the birds of Costa Rica including Cocos Island’ (1910), contains handwritten annotations by Robert Ridgway (1850–1929) that pertain to three type localities from his 1905 and 1908 expeditions with José Castulo Zeledón (1846–1923): Bonilla, Coliblanco and Guayábo. Hundreds of specimens in modern collections were taken at these localities, including the types of Zeledón’s Antbird Hafferia zeledoni (Ridgway, 1909) and eight other taxa currently treated as subspecies. The annotations also reveal discrepancies between primary and secondary sources, which cast doubt on Francisco Basulto’s role as collector of the holotypes of the northern subspecies of White-ringed Flycatcher Conopias albovittatus distinctus (Ridgway, 1908) and the south-eastern subspecies of Fawn-throated Foliage-gleaner Automolus cervinigularis hypophaeus Ridgway, 1909.