About halfway into my 25th year at the Bufferlands, participation in the Rio Cosumnes Christmas Bird Count (CBC) and looking at our historical data provides an occasion to assess what's going on at the Bufferlands and in the region. On January 3, 2022, seven Bufferlands staff and four volunteers participated in the 26th running of the count. It was great to resume this tradition, with precautions, after last year's count was canceled because of Covid-19. The Bufferlands is at the northwestern portion of the 15-mile diameter CBC circle that includes Stone Lakes National Wildlife Refuge, Cosumnes River Preserve, western Elk Grove, northwestern Galt, and a portion of Merritt Island in Yolo County. We recorded 109 species on the Bufferlands and the Sacramento Regional Wastewater Treatment Plant (totaling about 3,500 acres), within a historical range of 90 to 120, and counted 77,094 birds (60,000 were European Starlings), within a historical range of 7,723 to 811,644 (again, mostly starlings). The cumulative total is 163 species found on the Bufferlands over the count’s 26 years. New for us this time were a Western Grebe and a Semipalmated Plover.
Semipalmated Plover, image by Chris Conard
Large numbers of Snow Geese and Greater White-fronted Geese have been increasing in the past ten years and that trend continued. Diving ducks on Upper Beach Lake have long been a Bufferlands hallmark, though numbers have been pretty modest in recent years. For the first time since 2008, we had 2,000 Canvasbacks as well as a count record of 7,002 Ring-necked Ducks. Wild Turkeys were first recorded on our portion of the count in 2003, but are now up to an impressive 463, just down from last count's record high. We had only four Ring-necked Pheasants, down from a staggering high of over 400 in 1996; this species is declining throughout the region. Perhaps an echo of the recent drought years, we missed several species that have been declining on the property: American Bittern, Green Heron (found count week), and Common Gallinule. Raptor numbers were low, with some species (White-tailed Kite and Northern Harrier) alarmingly so. Some of this may relate to the evolving character of the landscape. Open space has been lost surrounding the property, but the Bufferlands has changed significantly too. It is much more forested than it was 20 years ago, which is a good thing to a large extent, but there are winners and losers when it comes to localized habitat needs. Despite steep declines in Sacramento County and the region, Burrowing Owls are (barely?) holding on, with four recorded on count day.
Varied thrush, image by Chris Conard
Other notable observations included an impressive 422 Mourning Doves, with an early morning flyout from a roost in sandbar willows of over 250. We missed Black-bellied Plovers for the tenth count in a row; gone are the days when we could find up to 1,000 roosting. Loss of foraging in the surrounding areas as ag lands fill in might be the cause. Two species that have declined since 2005 when West Nile Virus arrived in our area, Yellow-billed Magpie (60 this year) and Loggerhead Shrike (eight), showed encouraging and somewhat surprising increases. Common Ravens (7) and Say's Phoebes (17) both set count records. The latter is one of the few open country/grassland species that is not declining regionally, and it also bred on the property for the first time in 2021. Western Bluebirds were way up, with 24 being a new record; they have only been regular on the property since 2014. Golden-crowned Sparrows (202) outnumbered White-crowned Sparrows (190) for the first time; maturing habitat may favor Golden-crowned Sparrows. Lastly, a single Golden-crowned Kinglet and a single Varied Thrush were both unexpected in a winter season when these somewhat irruptive species have been scarce.
More background on the Rio Cosumnes CBC and other counts in the Central Valley can be found at the Central Valley Bird Club webpage.
Golden-crowned Kinglet, image by Dan Brown