Where did we go?
Our last trip of the year was to Arrowhead Marsh near the Oakland Airport. This is our own "backyard" – a place to observe wildlife right here in Oakland. Arrowhead Marsh is an island of wildlife habitat surrounded by an urban landscape. The Oakland Airport is one mile west of the marsh. The passing traffic on Interstate 880 and the jets flying over the marsh creates constant noise pollution.

What did we do? Canoes and Sloughs guides led our group through the marsh in canoes. Naturalists and museum curators explained the history of Arrowhead Marsh and identified plants and animals that live in the marsh habitat.	Erik samples the marsh mud after testing the water’s salinity with a hydrometer.
What did we observe? We saw many different kinds of birds and lots of small fish swimming in schools. In early summer, you can view nesting birds, such as barn swallows and terns. A large colony of nesting terns tried to ward off our canoes as we approached their nesting sites. We spotted many herons and egrets and even a flock of white pelicans flying overhead as we paddled. Earlier in the spring, this area is full of migrating shorebirds and waterfowl.	In early summer you can observe nesting birds, such as these barn swallows.
After loading all the canoes onto the trailer, we posed for a final group photograph.	Important facts about Arrowhead Marsh Although Arrowhead Marsh looks like it has been around forever, it was accidentally created by human activity a little more than a hundred years ago. In the 1870’s Chabot Dam was built in the Oakland hills. The dam was poorly engineered and soon after its completion a heavy rain destroyed the dam’s bypass. The rain washed 22,000 cubic yards of mud (or the equivalent of 400 standard dump trucks) down the San Leandro creek. The deposition of this sediment in south Oakland bay waters led to the creation of Arrowhead Marsh. The name of the marsh is an appropriate one as the marsh looks like an arrowhead from the air.

Is this native or exotic cordgrass? It is very difficult to distinguish these two species apart.

Today, Arrowhead Marsh is an important habitat for estuary plants and animals. The salt marsh harvest mouse and the clapper rail are two endangered animals that depend on the conservation of Bay Area marsh habitats like Arrowhead Marsh. Thousands of waterfowl make pit stops at Arrowhead Marsh during their seasonal migrations. If you are lucky, you might see the small and cute burrowing owls.
Despite the tremendous efforts to preserve and rehabilitate this important marsh habitat, several problems are still unresolved. Noise pollution from overhead jets and freeway traffic may deter many birds from Arrowhead Marsh. Scientists are baffled about eradicating an exotic cordgrass plant (Spartina alterna flora) that is displacing native marsh plants at a disturbing rate. If this non-native cordgrass continues to spread unchecked, scientists worry that the ecology of the marsh may be irreparably altered. So far, no easy solution has presented itself. Removing non-native cordgrass is expensive and wrought with legal problems. Furthermore, it is hybridizing with native cordgrass species that makes it even more difficult to distinguish these two similar looking species.