Written by Eric Gneckow for the Petaluma Argus-Courier.
Many hundreds of bird species have made an appearance in the expansive wetlands of southeast Petaluma, delighting birders and casual observers alike. But every now and then, one species takes the spotlight.
In what one wetlands activist described as a potentially once-in-a-generation event, a group of white-faced ibis is offering itself up for an extended viewing in the habitat around Petaluma’s Ellis Creek water treatment plant.
“This is the first time we’ve had a flock that have apparently decided to winter here, as opposed to stopping in to relax, maybe grab a quick snack and move off. It’s an unusual thing,” said Bob Dyer, senior docent with the Petaluma Wetlands Alliance.
Whether a one-time fluke or the start of a long-term shift, Dyer said the birds, which are among the 231 avian species recorded in the area, appear to be settling in for the time being. He has been observing and photographing 10 of the lanky, long-beaked birds at the wetlands around the facility since Jan. 15.
The migratory species has a range that generally only goes as far north as Southern California during the winter, part of a broader migration pattern spanning between western Canada and South America.
Adapted to shallow water and marshy environments, the white-faced ibis has a long, curved beak, sinewy legs and subtly iridescent plumage that shimmers in the sun. The birds take their name from the white plumage around the eyes that becomes far more prominent during the breeding season, meaning that Petaluma’s animals have taken a darker hue for this time of year.
The species is most common in areas around Southern California and Mexico during the winter, with many migrating north during other times of the year, according to information from the National Audubon Society. The white-faced ibis is generally uncommon in the Bay Area and North Coast regions of California.
Careful watchers may catch a glimpse of the birds in Petaluma’s skies or marshes during the migrations of a typical year, but the extended stopover in the city is turning more heads than usual, Dyer said.
“Every person that I run into at Ellis Creek who are not birders still say, ‘What are those?’” he said.
The group appears relatively comfortable with human interlopers — Dyer said he recently got within 10 feet of a small gathering of white-faced ibis, making for striking photos as the birds probe the shallow waters in search of food.
The arrival of the ibis is causing a stir among birders at a time when many are already keeping a close eye on the areas around Ellis Creek, Shollenberger Park and the Alman Marsh, said Gordon Beebe, president of the Sonoma County-based Madrone Audubon Society.
“The winter is a real time of rich diversity at the ponds, Shollenberger, the whole area, for waterfowl and shorebirds,” he said. “You get a lot of variety of species. It’s a great time of year.”
Contact Eric Gneckow at eric.gneckow@arguscourier.com. On Twitter @Eric_Reports.