This is from an email sent out 1/2/09 by Don Roberson (of fame):

Elkhorn Slough National Estuarine Research Reserve has been my CBC territory on the Moss Landing CBC since 1983. Late this afternoon I happened to be entering the 1986 totals from the Reserve into ebird [I’ve been entering old data in small bits when time permits]. Boy, how some things have changed in 23 years here!

Some examples:

Gadwall   500 in 1986,   40 in 2009,  more than 12 times fewer
N. Pintail   3400,   215   almost 16 times fewer
Green-winged Teal  1200,   135   almost 9 times fewer

ducks are generally down in California in recent years, but the totals at
ESNERR are waaaay down because the reserve has changed.  In 1986, the
water areas were a freshwater/brackish mix.  Since then the levees have
been breached and the water areas are almost entirely tidal.  Now, those
areas are heavily used by tidal mudflat waders and gulls.  Some examples

California Gull   12,   1800   150 times greater
Western Gull   3,    225   75 times greater

But some ducks may benefit with the salt water: for example, Bufflehead
numbers (126 yesterday) are double the 60 in 1986.

Back in 1986, the marsh was full of avocets (60) and a few BN Stilts (3);
none yesterday.  Because the marsh had fresh or brackish water, it was
cruised by swallows (9 Trees, 1 Violet-green) in ’86; no swallows
yesterday.  But yesterday a pair of Raven flew over — that would have
been astonishing in 1986.

Although the Reserve water areas are much changed, the land portions are
pretty much the same and are surveyed in pretty much the same way. I keep
these numbers in a notebook during the day’s walk one by one, so these are
not estimates, and the numbers are damn close:
Anna’s Hummingbird  11 in ’86, 11 yesterday [and no, they are not the same
birds . . . ahem]
CB Chickadee  27 in ’86, 21 yesterday
Oak Titmouse   4 in ’86, 10 yesterday
RC Kinglet  24 in ’86, 29 yesterday

Don’t know what it all means, but doing the same territory year after year
does give one some perspective on how things do change, and on things that
do not …..

Don Roberson