Although Baja California has not experienced loss of wetlands comparable in magnitude to that in California, some habitat changes have provoked changes in the abundance and distribution of wetland avifauna. This paper document ocurrence and changes in avian composition a long the wetland complexes in Baja California. Threats to the wetlands are primarily from resort and industrial developments being planned by international companies. Conservation of these vital avian habitats is a matter of concern to all ornithologist.

Waterbirds and raptors were recorded in this paper. Between November 1^st 1974 to April 3, 1975. A total 128 days of field observations plus additionals sightings were made in January 1972, 1976 and November 1979. Birds was conted from a 25 km road that begins at the motels and makes a complete loop of the central peninsula, most observations were made from 12 points along the route, the observations takes 2 to 4 hours. Twelve species was recorded ten waterbirds and two raptors. Some additions to the avifaunal informations on this area previously published in Grinell (1928) and Friedmannn et al. (1950).

A 93 water and terrestial bird list, sites observed were around the bay, Old Mill area, Punta Azufre and along de road between Ensenada- Camalú- San Quintín.

A discover of two or three calling Black Rails (Laterallus jamaicensis) at Bahía San Quintín on February 19, 1991. In the southeastern portion of the estuary in the pickleweed (Salicornia spp.) marsh near to house. The California Black Rail (Laterallus jamaicensis coturniculus) is known only from California, Arizona and northwestern Baja California. The California Black Rail is listed as threatened by the State of California, Endangered by the State of Arizona, and a Category 1 Candidate for threatened or endangered status by the U.S. federal government. In Baja California there have been no other Black Rail reports since early in the century. Grinnell (1928) listed all previous records: specimen taken on the San Simón River at Bahía de San Quintín. Two specimens taken at San Telmo, specimen taken from a "tule swamp" at San Ramón, at least one heard at Sangre de Cristo. It is hoped that a population is still resident in the extensive estuary at San Quintín.

This is an annotated list of known avifaunal records of Baja California, México with an introductory section an habitat and conservation, a bibliography of Baja California ornithology, and an appendix of place names, a checklist, and an additional reference section. It summarizes current distributional knowledge on Baja California avifauna (and the nearby Gulf of California) and provides future workers a baseline against which future expected changes in avian habitat and bird distribution can be compare.

Field work was conducted between the international border and El Rosario. A 40 specimens were collected from 19 localities between 16 January and 27 February and again in December 1991. The gnatcatchers were collected with a mist net. Captured birds were sacrified or released. The California Gnatcatchers of Northwestern Baja California represent a previously undescribed subspecies, hitherto included under Polioptila californica californica, for which we propose the name Polioptila californica atwoodi. Ranging from about Ensenada and Valle de las Palmas south to El Rosario, it differs from nominate californica in the paler, grayer (less brownish) back, flanks, and crissum of females. Males differ in only rarely having faint brown tinge to the back frequent in nominate californica . From Polioptila californica pontilis, the subspecies of central Baja California, both sexes of atwoodi differ in their darker upperparts and gray, not whitish, underparts.

In the peninsula of Baja california the only breeding colonies of Caspian Tern known so far are Scammon´s Lagoon and Laguna San Ignacio both of these colonies are located south of latitude 28° in the state of Baja California Sur. This note report an additional small breeding colony at Laguna Figueroa (30° 40´N), the first for the state of Baja California. This lagoon was visited on 7-9 May, 28 May and 22 June 1991. Results were first visit, same breeding birds reported previously, second visit one pair of Caspian Tern one individual alone, and a nest with one egg, third visit 22 individuals (10 pairs), six nest with one egg, three with two eggs, two eggs broken by predators and a few empty nest scrapes.

Even after the contributions of Wilbur (1987) and several recent reports in Western Birds, the distribution of many birds in Baja California remain poorly known. Observations report in this paper were made by the authors separately or together between 1975 and June 1994. But this paper only include data for northwestern Baja California, that is, between the international border and Río de El Rosario and west of the summits of the Sierras Juárez and San Pedro Mártir. Almost all the records are based on sight identifications only, owing to the difficulty, even for Mexican citizen, in complying with current collecting regulations in México. A total of 44 birds were sighted in 42 sites visited.

This paper report a survey of the breeding birds of Laguna Figueroa and La Pinta pond, Baja California. A total of 7 species were counted six of them were reported in both sites.

Present a listed for all previous records of Black Rails (Laterallus jamaicensis): specimen taken on the San Simón River at Bahía de San Quintín. Two specimens taken at San Telmo, specimen taken from a "tule swamp" at San Ramón, at least one heard at Sangre de Cristo. It is hoped that a population is still resident in the extensive estuary at San Quintín.