Paynter's (1955a) system of vegetational zones on the peninsula is useful to ornithologists. He recognized three zones: Scrub, Deciduous Forest, and Rain Forest. The Scrub zone occupies Isla Holbox and Isla Mujeres and the arid northern coast of Yucatán. The zone extends only a few miles inland and consists of low-tropical thorn forest of mesquite (_Prosopsis_), _Mimosa_, _Yucca_, _Agave_, and mangrove (_Rhizophora_) wherever standing water occurs. Sisal in Yucatán and Isla Mujeres of Quintana Roo are in this Scrub zone. The Deciduous Forest zone is a vast area of low, semiarid, secondary forest occupying all of the state of Yucatán not in the Scrub zone, northern Campeche, and a thin strip a few kilometers wide in Quintana Roo along the Yucatán-Quintana Roo border and a similar narrow band along the eastern coast. The island of Cozumel is also included in this zone. Collections were made in the Deciduous Forest at Champotón, Campeche, Isla Cozumel and Puerto Juárez, Quintana Roo, and Pisté, Yucatán. The Rain Forest zone occupies the remainder of the peninsula and includes most of the territory of Quintana Roo, and the southern half of Campeche. Collections were made in this zone at Escárcega, Campeche, and at Felipe Carrillo Puerto and Pueblo Nuevo X-can, Quintana Roo. Isla del Carmen cannot be accurately assigned to any of these three zones because most of the island has been planted in coconut palms. It is an area of high rainfall and may once have supported rainforest. In the present report the term "second growth" refers to areas that have been recently cut over. In these areas, the forest is characteristically low and in a stage of transition. In the Rain Forest zone "second growth" areas usually contain species of deciduous trees. Paynter (1955a) has given an excellent descriptive summary of the topography, climate, and phytogeography of the Yucatán Peninsula and there is little need to go into further detail here. During summer, the rainy season, the Deciduous Forest is much more luxuriant in appearance than in winter when most of the trees have lost their leaves. Also, the numerous _cenotes_ in this zone support a limited growth of evergreen trees. For example, the large Cenote Seco about two kilometers east of Chichén-Itzá contains elephant ear (_Caladium_), mamey (_Mammea_), figs (_Ficus_), and other large trees the trunks of which are some 10 meters below the surface of the surrounding tableland. These plants project five to 10 meters above the surrounding low forest. The floor of this _cenote_ is near the watertable but not below it. GAZETTEER The specimens of birds reported herein were collected at the localities shown on the accompanying map (Fig. 1). These localities are listed below in alphabetical order according to states. Campeche