In order to establish a relevant context in which to consider California’s records, each species account starts with a brief overview of the bird’s global distribution and basic migration habits. We have attempted to provide range information that is reasonably complete, accurate, and current, with the competing goal of not getting bogged down in excessive detail. The following section, entitled “Additional Important Information,” describes the sources and methods used in assembling this book’s range descriptions. In describing species’ overall patterns of vagrancy, we have provided extra detail about occurrences in western North America, which are more relevant to the California status than are those from more distant lands. Readers seeking authoritative information on the status of birds outside of California should always refer to the original sources. The first paragraph normally also touches upon taxonomic issues, including information about the subspecies or subspecific groups involved in California’s records, following the AOU (1957, 1998) plus supplements to the AOU Check-list through the 47th (Banks et al. 2006). As discussed on page 12, however, the order of the species accounts conforms to the AOU Check-list as amended through the 46th Supplement (Banks et al. 2005).

The second paragraph summarizes the species’ history of occurrence in California, starting with the first acceptable record. If details of a first state record are published, we cite the reference, and in cases where the first record involves a specimen we have attempted to track down the institution and catalog number. We provide this information in the narrative unless it is given in the record table. For species with only one to a few records in California, there may not be much more to say about their status in the state, but for most species the accounts provide such information as the species’ typical periods of occurrence in the state, major peaks in the temporal pattern of records, patterns in the geography of records, trends in the frequency of occurrence, and mention of any particularly unusual records. These discussions normally reflect analysis of accepted records in the CBRC database as supplemented by the literature. In cases where a species’ records were reviewed for only a brief period, information presented in the narrative necessarily amounts to a summary of the relevant literature.

Maps are provided for native species recorded at least 50 times in the state, except for Murphy’s and Cook’s Petrels and the Common Redpoll, species for which the value of a map would not justify the space required. We have also mapped the records of certain other species that show interesting patterns of distribution in the state. Some accounts include one or two charts showing the temporal distribution of records. Charts may depict the pattern of occurrence in California by time of year, from year to year, or from decade to decade.

When specific California records are discussed, the location and county of occurrence are normally given. For readability, however, oft-mentioned Southeast Farallon Island is normally written without indicating that it lies within the political boundaries of San Francisco County. Identification issues are seldom addressed directly, but relevant references are normally cited for species that pose particular challenges.