Martinez Beavers and Hydrology

I was just looking up dates and realizing that this time last year we had flocks of scaup flying up over the dams to feed in Alhambra Creek. I think one morning Cheryl counted 30. I was assuming it was later in the year but this picture of mine was taken at the dam and dated February 14th (and don’t I have a romantic life!) Yesterday I did another scaup search. Where are they?

Scaup are an interesting, carnivorous duck that feed on mussels or clams and have the dubious distinction of being able to “play dead” if caught by a predator. We were never sure if they were Lesser or Greater Scaup, because the two species look very alike are are typically differentiated by the presence of absence of salt water. With Alhambra Creeks brackish tidal mixed drink it is anyone’s guess. Last years’ highwater (before the flow device was installed) and then the sudden lowering in January created a bigger mussel population, so maybe that’s why they came then and were less enticed this year. Or its possible the broad barren dredging project discouraged them.

Or maybe they just don’t like sheet pile.

Still, the increase in scaup last year was something of an estuary “coup” since the San Francisco Estuary Project’s State of the Estuary Report described declining scaup every where in the bay area, and didn’t realize the Martinez had gotten lucky!

Keep your eye out for our missing feathered friends, and write if you see anything swimming that looks like an oreo cookie.

UPDATE:

Reader CM writes “Saw one scaup swimming alone just north of starbucks on Monday”. Hear that team? Go find some others….Thanks CM!

Last night’s visit to the dam showed four rascally kits, a yearling, and a very loud chorus of Pacific Tree Frogs. I remember when they showed up last year: (January 27th) after a rain, all at once, almost as loud as traffic. These are the males who come to gather and advertise for a mate. They use “ephemeral” wetlands that temporarily hold enough water for mating, but won’t run as great a risk of their offspring getting eaten by fish.

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In the days after their population explosion we got our first scaup visitors, and oddly all the frog song got alot quieter. Turns out that scaup are carnivores, and they probably climbed this creek looking for the tastey makers of that song. I thought at the time that the song ceased because the adults been eaten, but actually the “mating advertisement” ceased because the campaign had been successful. Procreation had occurred and eggs were laid. I’m sure the Scaup enjoyed the tadpoles.

The 2008 state of the estuary report says that scaup are declining in number in practically every watershed in the Bay Area. Except Martinez, where there were flocks of 30-50 seen for the very first time.

Listen for the frogs and watch out for their predators. Apparently the females don’t make any noise and that’s how the males know who to breed with. I read that they sometimes accidentally choose a soft-spoken salamander by mistake. Keep that in mind while you enjoy them, and make a noise or two just to be on the safe side.

They seem to be farther down this year, more towards the fourth dam. I think Hess scraped away their favorite places. Hmm. Some of mine too.