EXPLANATION OF COUNTY STATISTICS
COUNTY LISTS: These totals are primarily derived from the local experts who are acknowledged on each county's page. Ideally, only properly documented species are included on each county's list. For California Bird Records Committee (CBRC) review species, this means a record has been accepted by the CBRC or (for more recent reports) is currently undergoing CBRC review and the local consultant considers the record acceptable (the occasional variations are discussed below). Following a decision by ABA's Rules Committee, "supplemental list" records are also countable, as are those records "statistically accepted" in CBRC annual reports. For non-CBRC review species, local authorities have compiled their county lists from the literature (including Grinnell & Miller's classic 1944 Distribution of the Birds of California), from seasonal reports in North American Birds and predecessors, and from the notes of many local observers. Exceptional rarities should have been documented (acceptable written details, photos, specimens) or have been peer-reviewed in some other manner. Recent claims of new county records should have been published in North American Birds.
The list total is based on current AOU taxonomy. The total includes extirpated native species within a county and also includes those introduced species considered acceptable on the main California list by the CBRC and which have an established population in the county. John Sterling, who has done much to popularize county listing, recommends that county lists be compiled without such introduced species (this is known as "NIB" = no introduced birds). Many county birders (esp. in s. & nw. California) use NIB totals for county lists but include "IBs" on Big Days. While this compiler is sympathetic and his own World List is totally NIB, it seems likely that the majority of county birders include a few standard introduced species. For all counties these are Rock Dove, E. Starling, and House Sparrow. Central Valley counties include Ring-necked Pheasant; foothill counties often have established Wild Turkey; and urban southern counties have Spotted Dove. Chukars are established in a few arid regions. Finally, an established population of White-tailed Ptarmigan exists in alpine habitats from Ebbetts Pass ALP to the Ritter Range MAD. The NIB adjustment is thus 4-5 species for most counties. [The presence of pheasants or chukars which are the result of on-going releases for hunting, into habitat in which a permanent population cannot survive, does not make them countable, even if they occasionally breed. There must be a self-sustaining, long-running, and permanent population (meeting the CBRC bylaw definition) for any species outside its native habitat. Examples of small or transitory populations which should not be counted are pheasant or chukar in MTY or cardinal in LA. On the other hand, reintroduced birds into what was once their native habitat are countable once they begin breeding there again, even if their numbers are small.]
All county lists used here include offshore waters up to 200 nautical miles or half-way to the adjacent county's land, whichever is less. Offshore islands are considered "land" in determining boundaries, consistent with worldwide principles of international law. Thus an offshore birder within 200 n.miles of any part of California need only ask "what is the nearest point of land?" to determine which county should be assigned a pelagic bird observed. Often that nearest point of land is one of the Channel Islands (each is part of a specific county; see California Government Code or any good map) or the Farallones (San Francisco Co.).
The vast majority of statistics compiled rely on CBRC acceptance of exceptional rarities. Occasionally, a local authority will deviate from a CBRC decision when unique extenuating circumstances exist. An example is a Wood Thrush at Sunnybrae, Humboldt Co., 15 June 1984. It was a singing male but very difficult to observe. Nonetheless, the characteristic song was heard by numerous local observers and tape-recorded. Some glimpsed an appropriately large & red-backed thrush. Alas, since the song was taped few field notes were taken. When it came time for CBRC review, the tape-recording had been lost. Thus, some CBRC members considered the record inadequately documented [see Western Birds 26: 24 (1995)]. No one has ever raised any concern about the correctness of the i.d.; it was the adequacy of the documentation that was debated. For the local HUM observers there is no doubt a Wood Thrush was present, and it does appear on the HUM county list. However, such unusual circumstances (the loss of conclusive documentation) rarely occurs and the county lists used here do follow CBRC decisions in all but a few unique cases.
A member of a "species/pair" (e.g., White/Black-backed Wagtail) is included in the list totals until there is a record of one of the specific species.
For all these reasons, it is possible that the county list total found on these pages will differ from the total found on checklists to which we may provide links. The totals found are are the compiler's best updated effort after "vetting" other checklists against CBRC accepted records, North American Birds files, and local consultation.
TOP COUNTY LISTER: This is the highest current believable list after consulting some local experts, but it is possible that some higher lists were overlooked. We appreciate updates/corrections. In some instances, we may know who the top observer is but have been unable to obtain updated totals. On these occasions, approximately totals are given.
BIG YEARS: A "Big Year" is an effort to locate and identify as many species within a given county in a single calendar year as possible. Records of Big Years compiled here have been provided by local authorities listed in the acknowledgments. Whenever possible, the taxonomy of older efforts has been updated to current taxonomy when evidence exists that additional taxa, previously considered only subspecies, were actually identified by the lister during the year in question.
Boundaries: Sometimes questions about the boundaries of counties arise. In cases where a bird is on the border of a county (e.g., in a river that separates two counties) it is where the bird is that determines the county, not where the observer is standing. If the bird flies or swims from one bank of the river to the other, it occurs in both counties. Where rivers separate counties, it is the "thalweg" (center of the main boat or ship channel) that is the border, not the geographic "center" of the river. Borders at river mouths do not change back and forth when the river changes directions; the actual permanent borders are detailed in the California Government Code or by recorded maps in county recorder offices. See the above topic for offshore boundaries used for bird listing purposes (official Gov't Code county boundaries only extend three miles offshore).
BIG DAYS: A "Big Day" is an effort to locate and identify as many species within a given county in a single calendar day as possible. Records of Big Days compiled here have usually been provided by local authorities listed in the acknowledgments, or were published in Birding magazine or other ABA supplements. When a compiler is known, he or she is listed first followed by a semi-colon; team members are listed alphabetically.
Because there can be a wide variety of ways to undertake Big Days, and because "bird-a-thons" (fundraising Big Day-like efforts) are popular, the American Birding Association (ABA) established official ABA Big Day rules about 20 years ago. These are published annually in ABA publications. In essence, the official Big Day rules require that there be a team that travels together and stays within voice contact distance at all times (except during "time outs" when no birds may be counted). Whenever any member of the team sees or hears a new species for the day, he or she informs the team and all team members must attempt to confirm that identification. In other words, everybody tries to confirm every bird claimed by the team and, at the end of the day, 95% of all species recorded by the team must have been recorded by every team member (this assures higher accuracy by a quick-moving team). No prearranged meetings with other birders are allowed during the day (in other words, a team cannot have folks "staking out" birds for them) nor may the team receive information during the day about where a bird is (unless it happens totally by accident). Staking out birds and getting information must all take place before the effort begins.
Many "bird-a-thon" Big Day-like efforts break some or all of these rules. Sometimes team members come and go during the day, sometimes the team splits up, and during some birdathons other birders "stake out" certain species for them and take the team to the bird when the group arrives. Other teams only count up their list at lunch, or after the day is over, with no effort for every team member to confirm every bird as required by ABA rules. None of these efforts is an officially accepted Big Day, but often it is these types of efforts that have been run in many counties.
In the statistics compiled here, a Big Day which bears a double asterisk (**) is known to have not followed ABA Big Day rules. These should be thought of as "unofficial" efforts but do give some guidance about what an official Big Day might be like in that county. All single-observer Big Days are also unofficial and bear the double asterisk. If a Big Day total bears a single asterisk (*) it means we don't know whether or not ABA Big Day rules were followed; often the information comes via third parties who don't know the answer to this question.
Only the Big Day totals which are not qualified by any asterisk are known to have followed official Big Day rules. The "asterisk-free" Big Days are those that qualify for "Champion" in ABA publications. In some counties there are non-official "Big Day-like" efforts that have higher totals than official ABA Big Days, but official ABA Big Days are almost always preferred in these county statistics because they are more directly comparable to other counties.
"BEST BIRD": This is the compiler's idiosyncratic choice, often helped by the nominations received from local authorities. Birds that are common somewhere in California may often be the most exciting birds elsewhere (such as pelagic species inland). Concepts such as rarity, uniqueness, aesthetics, and that particular record's place in history were balanced in making a choice. Often there are several candidates that warrant consideration; a "close second" is often chosen; and in some very birdy counties additional "contenders" show other good possible choices (and sometimes there could be many more than are listed).
As always, for any of the information presented, corrections or comments should be forwarded to the compiler, John Sterling at email@example.com