Bay Duck Behavior Questions in Emeryville

Jim Chiropolos
 

I have worked in Emeryville for 25 years and every day I park my car by Chevys and start the work day by looking at the bay.

For the past 24 years, in the winter, a large group of Greater Scalp (maybe 100 to 250 plus) has always been in the bay here to greet me when I park. This year in this location, I think the high count of scalp so far has been 25 and usually less than 5. The scalp have been replaced by lots and lots of Buffleheads! This week I have been counting 300 to 500 Buffleheads actively feeding from where I park in the morning. I do not think I have ever seen this many for so long at this area. The bay bottom here is muddy and the water is probably 2 to 4 feet deep and this is an area that is not exposed by the tides.

I am always amazed by how little we know about common birds we see all the time. I have questions that include:
1. Why have the greater scalp abandoned this area so far this year? (It seems to be a year of low scalp numbers in Emeryville)
2. Why have Buffleheads moved in this year to actively feed in this area in big numbers?
3. What do Buffleheads feed on that is different than scalp? Do Buffleheads feed underwater using a different behavior feeding behavior or action? Since they are smaller is the food items they feed on smaller?
4. (I have noticed over the years that Lessor Scalp prefer areas to feed that are exposed by low tides unlike Greater Scalp that seem to prefer deeper water).
5. Is what I am seeing a sign than the "Chevys" bay mud bottom ecology of marine invertebrates or whatever the bay ducks are feeding on is different?

I know so little of bay duck behavior despite considering them a "common" bird.
Jim Chiropolos
Orinda and Emeryville

PS - No sign of tufted duck after the spotting on Tuesday and the Bar-tailed Godwit has also been missing))

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