|Swifts at Healdsburg a Remarkable Sight |
September General Meeting
Get in the Migration with Pee Wee Audubon
Message from Our President
"Audubon Adventures": Act Now!
Docent Training at Bolinas Lagoon
Costa Rica Birding
Poster Contest: Sonoma County Kids Sweep Grade 3-5 Awards
Second Annual Leveque Lecture
Welcome New Members
Awards at Festive Annual Meeting
Environmental Educators to Meet in Bay Area
Fall Sanctuary Camp-Out
Swifts at HealdsburgONE OF SONOMA COUNTY'S most exciting avian spectacles canbe seen each fall on the campus of Rio Lindo Academy near Healdsburg, whenthousands of Vaux's Swifts return at dusk to roost in a single chimney. Thisyear, for the first time, Madrone Audubon will sponsor two visits to the roost,one led by Peter Leveque on Thursday evening, September 19, and one by ConnieJoachim on Wednesday, September 25.
a Remarkable Sight
Some Vaux's Swifts are known to summer and breed in Sonoma County, but theHealdsburg roost is mostly migrants, stopping here for about a month beginningin mid-September. Most evenings, they begin circling the roost about 45 minutesbefore dusk, and arrive in ever-increasing numbers, gradually beginning tofunnel into the roost and reaching their greatest concentration about 10minutes before sunset. By dark, most of the birds have entered the two-storychimney, and are clinging tightly packed along the upper 8 or 9 feet of itsinterior walls.
The roost has been active since at least 1990, and its population seems to bedeclining, according to Gottfried Fritz, who teaches biology at the Academy.Videotape in 1990 and 1991 yielded an estimate of 14,000 to 15,000 birds at themaximum concentration, while last year Connie Joachim and Marjorie McCulley ofMadrone Audubon estimated highs of less than 10,000 birds. The population alsovaries during the roosting period, peaking around the third week ofSeptember.
Historically, Vaux's Swifts roosted in hollowed-out trees or stumps, but theyappear to be using chimneys in response to diminishing native habitat,according to the Audubon Society Encyclopedia of North American Birds.The Sonoma County Breeding Bird Atlas reports evidence of Vaux's Swiftsbreeding in 31 of the county's 105 study blocks between 1986 and 1991, some ofthem in chimneys. Editor Betty Burridge received several reports of new nestsites in chimneys during the 1996 breeding season.
The Vaux's Swift is the smallest of North America's four species of swift,about 4 1/2 inches long, with a wingspread of 11 1/2 inches, andweighing about 2/3 of an ounce. The Vaux's resembles the Chimney Swift, but astheir ranges are different most birders can rely on geographic location forprobable identification.
Swifts are most readily distinguished from swallows by a more rounded,sickle-shaped wing profile, and short tail. The strong claws and spiny,needle-like tip on the tail of the Vaux's and Chimney Swift are well adaptedfor clinging to vertical surfaces.
Rio Lindo Academy has not restricted visiting of the swifts' roost, butobservers are encouraged to car pool, to park quietly at least a block from thechimney, and to observe from the opposite side of the facing street. TheAcademy is a residential, co-educational preparatory school with 220 students,which is operated by the Seventh Day Adventist Church.
The Madrone groups will be meeting at 6:15 PM at the corner of HealdsburgAvenue (Old Redwood Highway) and Bailhache Avenue, just south of the RussianRiver bridge. Those visiting at other times, follow Bailhache to the end (itbecomes Rio Lindo Avenue), and into the Academy's main entrance. Take a left atthe first stop sign, and another left just before the dormitory. In half ablock, turn right toward the rear of the campus. The chimney is on a sidestreet west of the athletic field. -JSB