Comments on the "Scope of Services" for the State Parks Waterbird Study of the North Sailing Basin
Thank you for providing me with a copy of the draft
"Scope of Services" for the North Basin rafting
waterbird study.
I have a number of comments, suggestions, and
corrections to various details in the draft. There
are two major elements missing, and one important
detail to correct:
1) Context of the Study
The study does not address the relative importance of
the North Basin to rafting birds in the context of
nearby locations.
See for example the chart of surf scoter habitat at
www.well.com/user/pk/waterfront/photo-of-the-week/Photo030623.html.
If this species is
representative, it suggests that the North Basin has
no unusual significance compared to other nearby
habitat areas, and is far less important than very
large subtidal regions to the north and south. The
WTA study that generated this chart was presumably
constructed from limited data, and one of the
purposes of the current study should be to verify or
modify this distribution of habitat, for this and
other species of concern.
The relative importance of the North Basin habitat
compared to other areas in the region is critical
information for any agency that must evaluate
possible trade-offs between habitat value and
recreational value.
2) Measurement of Population Impact
The study does not measure anything that will
directly assess the effect of non-motorized boating
on bird populations.
This is very hard to measure, but perhaps the
simplest way to analyze this effect is to expand the
geographic reach of the study to include the South
Sailing Basin, on the other side of University
Avenue. This is a sub-tidal body of water of
approximately similar size which, in addition to
major bird habitat, also supports several large-scale
year-round boating programs.
For example, the relationship of the mouth of
Strawberry Creek to the South Sailing Basin docks is
somewhat similar to the relationship of the
Schoolhouse creek outflow to the proposed boating
access facility in the North Basin. If boating
activity in the South Basin (which includes outboard-
powered support vessels) does not result in
significant degradation of the habitat at Strawberry
Creek, then it would be difficult to conclude that
less intense and less obtrusive use my non-motorized
boats in the North Basin would be damaging to
Schoolhouse Creek.
By studying the two areas together we will have a
unique set of "case" and "control" sites that might
actually lead to some useful scientific results.
Otherwise, we will only be restating what we already
know: Birds and kayaks can not occupy the same space
at the same time, and if you paddle a kayak through a
raft of ducks they will fly away and relocate nearby.
The real question is, what effect does this level of
disturbance have on the bird population? There is
nothing in the study that will really answer this
question. In fact, there is almost nothing in the
literature that answers this question. See, for
example, my January 2003 letter to the California
Dept. of Fish and Game
www.well.com/user/pk/waterfront/EastshoreStatePark/DFG-030131.html
Note especially how data on
disturbance is confused with the degree of damage to
the habitat. There are many studies that measure
disturbance, but virtually nothing that relates non-
motorized recreational uses to population decline in
non-nesting habitats like the North Basin. In fact,
the most applicable examples document thriving bird
populations coexisting with non-motorized
recreational uses.
Another example of the difficulty in relating kayaks
to bird population is found in the Brandt's cormorant
study by the Point Reyes Bird Observatory. From the
winter 2003 issue of the "Observer,"
www.prbo.org/OBSERVER/Obs131.pdf:
"In the past three years, we documented
disturbance to birds on and around Alcatraz at
some of the highest levels on record. In 2002,
nearby boat traffic caused one-third of all
recorded disturbances. Surprisingly, kayaks are
particularly potent vectors of human disturbance
because of their silence: they can sneak up to
birds and startle them more easily than can a
loud motorboat."
And yet, in the same article:
"The Brandt's Cormorant is the most numerous
breeder on Alcatraz; in fact, the number of
nesting pairs increased by 19% between 2001 and
2002, reaching the highest numbers ever
recorded."
The point is that measuring frequency of disturbance
and flushing distance does not necessarily measure a
negative impact on population. The argument is often
made that birds engaged in long migrations are
seriously energy-depleted and must rest to survive.
This is certainly true, but it is equally logical to
assert that since they are traveling hundreds or even
thousands of miles anyway, a short relocation adds an
insignificant increment to their energy budget.
Without actually demonstrating the effect of
disturbance on the success of the migration, it is
all conjecture.
3) Definition of the Study Area.
From paragraph 2 of the draft: "The North Basin is a
relatively sheltered bay, totaling roughly 220
acres."
We need to clarify the boundaries of this body of
water. The "sheltered bay" is the water to the east
(downwind) of the protection of Cesar Chavez Park,
part of the landfill that forms the Berkeley Marina.
This protected water is roughly defined by a line
from the north edge of Cesar Chavez Park to the foot
of Gilman Street on the east side of the basin. The
water area is 120 acres, not 220 as stated in the
draft. So it appears that some of the water to the
north, which is not sheltered by land, is also being
included in the study. See, for example, the
boundaries drawn on the aerial photo at
www.nasites.com/cmprojects/projects/eastshore/gallery.asp?name=gallery740.
If the boundary has been
arbitrarily moved to the north, then it is not
correct to describe the entire area as sheltered.
The water to the north is certainly used by rafting
birds, and there may be good reasons for including it
in the study. But this area is unprotected from the
prevailing westerly winds, and will presumably have
very different use patterns by birds seeking
protection from wind and waves.
This is more than an academic point: Access
improvements at the foot of Gilman St. are currently
being considered by Caltrans as part of their Bay
Bridge seismic retrofit eelgrass mitigation project.
This location is just outside the north boundary of
the sheltered water of the North Basin, and should
not be subject to operating restrictions based on the
habitat value of the more sheltered North Basin
proper.
4) Goals and Recommendations:
The draft identifies three distinct purposes. The
first is to determine the waterbird and shorebird use
of the North Basin. No problem here. But the second
purpose, "study the impacts that non-motorize boating
activities may have on rafting waterbirds" will be
difficult to achieve, for reasons outlined above. So
the third purpose, "provide recommendations and
management guidelines for boating activities…," will
necessarily be made with less then complete data. The
North Basin Rafting Waterbird Study should enable
planners to make good decisions about possible water
access restrictions on the basis of science rather
than politics. It is unlikely that this goal will be
achieved by the study as proposed.
The most critical change that needs to be made in
this proposal is an expansion of the study area to
include bird counts in the South Sailing Basin, so
that the actual impact of boating on bird populations
can be measured.
The contractor should also make an assessment of the
relative importance of the North Basin to species of
concern in comparison to other habitat areas in the
region, so that the value of this particular bit of
waterway can be realistically compared to the value
of recreational uses if it is found that they are in
conflict.
The north boundary of the North Basin should be
clearly defined as a line from the north edge of
Cesar Chavez Park to the foot of Gilman Street. The
area north of this line is outside the area of
sheltered water, does not border land areas of the
Eastshore State Park, and does not have any special
geographic characteristics compared to other large
stretches of unprotected water along the East Bay
shoreline. By any reasonable application of language
and usage it is outside of the North Basin.
Finally, I extend an invitation to all State Parks
staff and their guests to come out for one of my
"three hour tours" of the North Basin, using one of
the larger sailboats operated by the Cal Sailing
Club.
Best Regards,
Paul Kamen
510-540-7968 pk@well.com
www.BerkeleyWaterfront.org