The Luck of the Bay Saver! Save The Bay Educator and Girl Scouts See Rare, Endangered Mouse

by Jill Jacobson

What does a Bay Area resident have to do to find the luck-bringing creature, the Salt Marsh Harvest Mouse? For years, I have read the tales of ecologists spotting these tiny creatures in the wee hours of the night and imagined it happening to me. Up until this past Saturday, the only mouse I had ever spotted was the one stuffed in an exhibit at the Palo Alto Baylands Nature Preserve. As one must conclude, I was skeptical and wary of the possibility that I may one day be lucky enough to see one of these elusive creatures.



My luck has changed! Finally after five years leading over 450 educational programs in the San Francisco tidal marshes for Save The Bay, I have successfully spotted a Salt Marsh Harvest Mouse! I am honored to be one of the first with Save The Bay to see this rare and tiny creature that is endemic to the San Francisco Bay.

The mouse was first spotted by a few Girl Scouts this past Saturday at 11:42 a.m. during a Save the Bay Girl Scouts volunteer planting day at the Palo Alto Baylands. One of the girls tugged on my sleeve and said "Jill, there is a mouse in the water, over here! Look!" The other girls were exclaiming all at once "How cuuuuttttee!" Sure enough, there was the Salt Marsh Harvest Mouse swimming at the water's edge. Cautiously, I signaled to the girls to step back to observe the mouse silently from a distance so as not to scare it away.

What makes spotting the Salt Marsh Harvest Mouse so lucky?
To start with, this creature is incredibly tiny, said to fit on the tip of your thumb and weigh about as much as a nickel or quarter. In addition to being small in size, this creature is endemic to the San Francisco Bay wetlands. With only 10 percent of the Bay wetlands remaining, the population of the Salt Marsh Harvest Mouse has declined over the past century, putting it on the endangered species list with a population under 2000. Finally, this mouse is nocturnal, making it nearly impossible to see the mouse under the sunlight.

So, why did we spot this mouse?
This mouse lives primarily in the pickleweed, a low zone tidal marsh plant that is often submerged under the brackish water during high tide. During the high tide, the mouse usually finds shelter in the mid zone plant species, like alkali heath or gumplant. During extreme high tide events, like this past Saturday, this mouse must find shelter in the higher zone plant species which sometimes do not exist, due to the development of roads, trails and parking lots. Over the past few years, Save The Bay has been working in partnership with the Palo Alto Baylands to restore these high or “transition” zone plant species to provide shelter and habitat for species like the Salt Marsh Harvest Mouse.

What does a Bay Area resident have to do to see a Salt Marsh Harvest Mouse?
Become a Bay Saver and join Save The Bay as a volunteer to protect and restore the habitat for the Salt Marsh Harvest and the hundreds of other animals that call our wetlands home! We cannot guarantee you will be lucky enough to spot this creature, but we can guarantee you will see wildlife and have a great day out on the beautiful San Francisco Bay!