January did more than usher in a new year — it also brought with it higher-than-normal ocean tides that provided rare bird sightings at Palo Alto Baylands Nature Preserve. Those exploring the Baylands on Jan. 12 to witness the season’s second occurrence of a king tide were treated to a rare sighting of a Ridgway’s rail tiptoeing through the pickleweed marshland behind the Lucy Evans Baylands Nature Interpretive Center. Due to the high sea level, the near-threatened bird had been forced out of its regular hiding spot along “rail alley,” a water channel in the marshlands that birds frequent. Other birds, including great egrets, northern harriers, ducks, sparrows, black phoebes and avocets also could be spotted nearby in the marsh, unafraid of the dozens of visitors equipped with zoom lenses and binoculars.
“Birds appear to understand they only have a few periods of time each day to hunt and eat, when the tides are just right. And for shorebirds, that means wading around in the marsh and at the edges of the water, sometimes near humans,” said Palo Alto naturalist Corinne DeBra, who led a walk at the Baylands on Jan. 12 to explain why these exceptionally high tides occur and show their impact on the flora and fauna in the marsh.
DeBra estimated that more than 1,000 people came to the Baylands to see the high tides, known as king tides. These tides, which can rise 9 feet — or more than 2 feet higher than the average tide — occur only a few times each winter when the Earth, sun and moon line up in formation during orbit. The first king tide of this winter occurred on Dec. 25, and the next king tide is expected to occur on Feb. 9.
Experts say king tides are good predictors of how sea-level rise will affect coastal places in the future. As time goes by, the water level reached now during a king tide will be the water level reached at high tide on an average day, according to the California King Tides Project, a group that helps people visualize future sea level by observing the highest high tides of today.
“You’re more likely to see things you don’t normally see,” DeBra said. “It’s an exciting time to look for endangered species.”
According to DeBra, birds are among the easiest species to watch. Some birds, she said, build nests that are used to float on the water during high tide. Those species that don’t adapt to these recurring high tides are often endangered.
King tides also reveal the uneven impact of sea-level changes, she said.
“The rise in sea levels is not happening evenly everywhere, not affecting everyone the same way,” DeBra said.
Even in the Palo Alto Baylands, there are parts that are affected more than others.
“This is an opportunity to see with your own eyes what a rise of 2 feet, of 3 feet means; there’s no substitute to experiencing this yourself and getting out in nature,” DeBra said.
For those who missed the January king tide hike, DeBra and the nonprofit group Environmental Volunteers will lead a joint-guided tour at the Baylands during the next king tide on Feb. 9 to compare its flooding impacts with the high tides from December and January. For more information, go to evols.org.