The New Sacramento Area Checklist
Great-tailed Grackle ©Dr. Corina Logan
The Sacramento Audubon Society has long produced checklists of the birds of the region. The checklist covers the area from State Highway 12 in the south to about State Highway 20 in the north, and extends east and west to the thousand-foot elevation. Thus, it covers all of Yolo County except the higher ridges and peaks of the Blue Ridge. The checklist is available on the Sac Audubon website.
Like the similar Yolo County checklist, it is revised from time to time. I have versions going back to 1951. The 1963 edition came out just as I got serious about birding in this area. I wondered how the checklists showed changes in bird abundance over that span. This column discusses the species that have increased in numbers. Next month’s will cover the birds that have declined.
Some of the winners are several divers, including common goldeneye, hooded and common merganser, western and eared grebe, and double-crested cormorant. Redhead now occurs in summer, and ruddy duck has become common at that season. The reasons for all this are obscure.
There have been big increases in numbers of white-faced ibis, black-crowned night heron, green heron, snowy egret and black-necked stilt, probably helped by large increases in wetland acreage. The expansion of alfalfa farms, with abundant mice, likely helped the herons, and boosted Swainson’s hawk numbers greatly.
Other species also gained from unintentional human intervention. Herring gull numbers exploded as local landfill acreage grew. Canada goose was absent in summer until the species discovered that the grass on irrigated parks and golf courses was a reliable food source. It established a toehold in the 1980’s, and was a common breeder twenty years later. Dark-eyed junco first appeared as a rare nester in about 2000. Now it breeds sparingly in urban forests, especially where there are conifers. It is remarkable that these two species overcame their migratory urge.
Osprey and bald eagle had been absent as nesting birds, probably as a result of widespread chemical poisoning. Bans on certain pesticides are at least partly responsible for their small but significant comeback in this century, here and around the country.
It may be hard to imagine, but the 1963 checklist had Anna’s hummingbird as uncommon, and white-throated swift was absent in winter and rare otherwise. Swifts have benefited both from the construction of highway overpasses for roosting and from the disappearance of tule fog in winter. Two other species that likely increased as a result of sunnier winters are turkey vulture and Townsend’s warbler.
Some wetland species are now present in winter, including white-faced ibis, black-necked stilt and Forster’s tern. The ibis was a rare passage migrant in 1963, and became regular year-round by about 2000. It makes sense that ibis and stilt responded to warmer winters, since their headquarters are in the tropics. The tern is more of a puzzle.
Finally, there are four species that were entirely absent fifty years ago. Wild turkey was released in our area for sport hunting in the 1980’s and was tolerably common by about 2000. Collared-dove, first introduced to the eastern seaboard, quickly spread west, arriving here about twenty years ago, and is now common. Great-tailed grackle spread to southern California from Arizona in the 1980’s and became noticeable here by the 2009 checklist. It is now fairly numerous.
Common raven was absent in 1963 and rated as very rare, mainly in winter, in the 1980’s. A few were present in summer by the time of the 2009 checklist. Now it is common all year. As I noted (December 2022), to escape persecution by shooters, the species took refuge in the mountain wilderness on either side of the valley in the early twentieth century. They slowly returned to our area only after they felt safe. This year, for the first time, a pair has made a nest in a city (Davis) in Yolo County.
— Michael Perrone, Conservation Chair