Diving into the world of ducks
As winter proceeds, we’re seeing record low numbers of migratory ducks in Marin.
Have you noticed that lately? As a wildlife observer who finds reassurance in abundance, I’m disquieted. Maybe it’s avian flu. Maybe it’s something more subtle or more complex or a combination of factors. Bottom line: My sightings this winter have been down — way down. My morning counts for the past 13 winters, conducted from my deck on the South Fork of Las Gallinas Creek, a mile east of the Marin Civic Center in San Rafael, show a precipitous drop in both numbers of individual migratory ducks and variety of species. Other experienced observers report fewer ducks at locations such as the Las Gallinas Wildlife Ponds in San Rafael, Corte Madera’s Shorebird Marsh and San Francisco’s Heron’s Head Park.
Yes, this may be a temporary and possibly reversible condition or a matter of natural cycles or recurring correctives in nature — or maybe not. It’s simply a data point from this time at a particular place.
As reported by Reuters on March 13, 2025, citing research by various scientific surveys, there are alarming declines in United States bird populations, even among ducks, which have, until now, been considered a conservation success story. Locally, a recent report by the San Francisco Bay Joint Venture and Point Blue Conservation Science found that shorebirds are facing rapid decline in the Bay Area.
I consulted an expert, Nils Warnock, director of conservation science at Audubon Canyon Ranch in West Marin, who has been monitoring waterbird numbers on Tomales Bay since 1989. Warnock reports a 65% decline in wintering shorebirds in that time, and since 2010 a decline in waterbirds, with some of the lowest numbers recorded last winter. A shorthand way to distinguish between shorebirds and waterbirds is that the former patrol and probe the edges, usually wading; examples: whimbrels and sanderlings, while the latter are the floaters, dabblers and divers; examples: canvasbacks and teals. He mentioned that in winters of either too much or too little rain, numbers can be depressed. He adds, however, that factors such as warmer temperatures, more and more people and less habitat make it tough being a bird.
Three duck species have been emblematic of winter life on Las Gallinas Creek — canvasbacks, gadwalls and green-winged teals. During the past decade, it was not unusual to see 20 to 40 canvasbacks from the vantage point of my deck. When the tide subsided, the craters they had excavated while feeding in the submarine mud were revealed. In sharp contrast, this winter the highest number of canvasbacks seen has been four. Gadwalls have suffered a steeper decline. In past years, as many as 80 regularly arrived. Only four have been seen this winter. As these two species dwindled, there was a pickup in the number of sightings of green-winged teal, which peaked at around 80. This year, there are usually fewer than two dozen.
Backing up to last few months of 2025, the scenario was as follows. After nesting in relatively undisturbed habitats on tundra, taiga, boreal wetlands and prairie ponds, waterfowl and shorebirds arrived here to be confronted with shopping centers, vast parking lots, clamorous freeways, housing tracts and all the congested tangles of human infrastructure covering over former wetlands. What marshes remained were largely channelized and diked and transformed into hayfields and cattle pastures. While diminished from historical numbers, the ducks and shorebirds somehow cope with this fundamental alteration of their habitats. This is surprising and even reassuring.
If Marin’s remnant wetlands provide a waystation and destination, it’s because local citizens cared enough to set aside these areas for protection. The Corte Madera Shorebird Marsh, the various marshes protected by the Marin Audubon Society, the Las Gallinas watershed and sanitation ponds, Hamilton’s restored wetlands, the Point Reyes National Seashore and our complex of state and federal lands are destinations for the winter migrants while serving as year-round habitats for an array of herons, egrets, rails, bitterns, geese, ducks, stilts, grebes and avocets.
The good news is that since 2017 more than 7,800 acres of San Francisco Bay habitat have been restored, thanks to voter-approved funding from Measure AA. Much of this restoration is in tidal marshes, critical habitat for many species.
More than 20 types of duck make up the local winter roster if you add in the three year-round resident species — wood duck, common merganser and mallard. Canada geese fly low in formation from night roosts along the bay to San Rafael’s Lagoon Park each morning. Less familiar to many are the brants — sea geese, which winter in considerable numbers at Limantour Beach in West Marin. I have spotted a solitary greater white-fronted goose in a gaggle of Canada geese at the recently restored wetlands in Corte Madera. More usually, this species winters in the Central Valley. This individual goose looked to me to be more lesser than greater, seemingly petite when compared with its companions, the towering Canada geese. But the lesser species occurs in the Eastern Hemisphere, nesting in such places as Siberia.
In winter, shorebirds, each species showing its unique feeding adaptations, populate the mudflats. The stately long-billed curlews stalk the water’s edge accompanied by an array of probers, sifters, spearers, stalkers and pokers, including nine migrants and a year-round community of dozens of shoreline specialists. The curlew will soon be nesting in such places as the wet meadows of the Ruby Valley in northeast Nevada. Its fellow travelers will go as far as Alaska’s North Slope.
To visualize the vast migrations undertaken by these winter visitors is to be awestruck. Once in a while, the wonder comes sharply into focus as the flash of 80 synchronized wings cuts the air as it did one morning in spring. On March 31, 2025, approximately 40 short-billed dowitchers wheeled a few feet above the creek surface before landing among another couple dozen of their kind on the mudflats.
It took me a while to distinguish this species from the similar long-billed variety. Guides recommend concentrating on their vocalizations, described as a soft “tu-tu-tu” in contrast to the alarm call — a loud “keek” uttered by the long-billed. These descriptions fall far short of capturing the complexity of their calls. Dowitchers are large sandpipers, which winter in coastal Mexico and California and migrate to nesting grounds in southern Alaska. We are likely to see them in winter plumage, more gray than brown.
Sometimes helpful in telling the difference between the two dowitcher species is that the long-billed tend to prefer fresh-water habitats, while the short-billed favor saltier zones like the Las Gallinas Creek, which wends its way through tidal marshes to its denouement in San Pablo Bay.
All of this identifying data amplifies the scientific part of birding. Knowledge increases appreciation. But the primary experience of being out there in nature is really about the unfiltered experience of beauty and the miraculous.
An artist, whose paintings are held in many museum collections, Marin resident Jeffrey Long has backpacked the mountains of the West and hosts the blog Konocti Post. His art can be seen at Jeffreylongstudio.com. He can be reached at jefflong@jefflong.com.