SAN LORENZO RIVER STUDIES: Bird Populations; Pilot Project 2014 Report  

Steve Gerow, 122 Bird Species Regularly Utilizing the Lower San Lorenzo River Area in Santa Cruz  A list compiled in 2015 by Santa Cruz County birding expert Steve Gerow.  The list includes species with a regular pattern of occurrence along the San Lorenzo River from Highway 1 to the mouth (excluding rarities and species that are very irregular or marginal to the river habitat. Also excluded are a number of primarily ocean, bay and beach species that occasionally go a very short distance up the river in the vicinity of the mouth (Surf Scoter, Brown Pelican, etc.) Click Here

58 Ducks, Waders, Shorebirds, August 1-November 30  A list of waterfowl and other birds, both migratory and year long residents,  that feed directly in the estuarine stretch of the San Lorenzo River during the fall months that are proposed as appropriate for boating.    This list was compiled by Barbara Riverwoman based on data submitted by Santa Cruz birders to eBird, a bird data collection project run by the Cornell Laboratory on Ornithology (see below) Click Here

Cornell Laboratory of Ornithology, eBird Bar Charts on the San Lorenzo River,  1999 to 2014 This internationally known research center  provides rich data sources for site specific information on bird abundance and distribution utilizing  submissions from birders in local areas.  The eBird bar charts break down data by month as well as by site.  Click Here

Jane Mio, Lisa Sheridan and others, Report on the Negative Effects of Recreational Boating on Birds Created by Pilot Project 2014, April to August.  This detailed report vividly documents  the disruption to bird life caused by the original Pilot Project on Recreational Boating in 2014.  It was led by Jane Mio who has regularly birded the San Lorenzo River for over a decade and was very familiar with the bird life on the river.  Although not a scientific study, it offers a serious look at what happens when boaters enter an important bird habitat.  In addition to constant agitation of birds who were unable to feed, three birds were killed (a juvenile Green Heron that was driven from the reeds into the open where a peregrine falcon was able to capture it, and two American Coots that were driven up onto the highway and killed by collision with automobiles.)


Jane Mio, Why I Voted No

Barbara Riverwoman, No Boating On The San Lorenzo River



 San Lorenzo Urban River Plan   A twenty-year plan for the San Lorenzo River adopted in 2003 by the Santa Cruz City Council.  A must read in order to understand the current politics of the River!  According to the introduction to the Plan,  “In 1999 the Santa Cruz City Council initiated a new phase of planning for the San Lorenzo River, Jessie Street Marsh and Branciforte Creek. The City Council appointed a citizen committee, the San Lorenzo Urban River Plan Task Force (Task Force), to update plans for these waterways and asked the committee to undertake a planning process that would result in recommendations for programs and projects that would enhance the habitat, safety and aesthetics of these waterways within City limits. The City Council’s interest in providing updated plans for the River, Creek and Marsh was instigated by several significant events: the initiation of the U.S. Army Corps of Engineers flood control improvement project beginning in 1999; the listing of the steelhead trout and coho salmon as federally threatened species; and federal designation of the San Lorenzo River as critical habitat for these species.”  Click Here

Swanson Report, 2002  Officially titled the Lower San Lorenzo River & Lagoon Management Plan, this  127-page report was commissioned by the  City of Santa Cruz  to provide basic environmental data for the work of the Task Force mentioned above.  It is was produced by three consulting firms, Swanson Hydrology & Geomorphology, Native Vegetation Network and Hagar Environmental Science, and is included as an appendix and official part of the San Lorenzo ran River Plan cited above.  The goal of the study was ” based on a multi-species approach to habitat enhancement and identifies the primary physical, chemical and biological processes necessary to build a framework to support a more developed biological web.”  It  provides a list of management and restoration goals and objectives, as well as implementation and monitoring plans.  The last two thirds of the Report are a rich resource of data on everything from plant, fish and bird species found on the River to charts, drawings and detailed directions for management, including the width of trees to be cut and the natural and artificial structures needed to  enhance fish habitat.  (The Report unfortunately lists only 66 species of birds on the urban stretch of the river although a current count tops 200.) But beware!  Once you enter this document you may never find your way out.  It is fascinating if you are interested in the River. It should serve as a major resource for anyone seriously considering habitat restoration on our beloved San Lorenzo River.  Click Here


Center For Biological Diversity,  Press Release 2014: CDFW  Wins Case Against COE  This press release announces the successful result of legal action that the Center for Biological Diversity and other environmental organizations brought against the Army Corps of Engineers’ charging the COE with  irresponsible removal of vegetation from levees throughout California and elsewhere.  The decision seems to put a hold on further vegetation removal until the COE has completed a review of its policy.  Click Here


Kathi L. Borgmann, A Review of Human Disturbance Impacts on Waterbirds   This 23-page scholarly study reports on Borgmann’s review of 50 unpublished and peer-reviewed published studies that “examined the effects of human disturbance on waterfowl, diving duck, wading bird and shorebird species that occur in the San Francisco Bay area.  86% of these studies reported that human-caused disturbances impacted the study species. Human-caused disturbances such as boating and walking were shown to alter waterbird behavior, diverting time and energy away other essential behaviors such as feeding.”   She recommends that establishing set-back distances of 250 meters (820 feet) ‘may lessen the impacts to the most sensitive species.” Click Here

Monterey Bay National Marine Sanctuary Recreational Boating”. Check out the 6th  paragraph of this document where it says,  “Motorized vessels and hand-powered boats (kayaks and canoes) have been shown to disturb and/or lower reproductive success in a range of pinniped, whale, and bird species when operated too closely to these animals. Studies in Three Arch Rocks National Wildlife Refuge in Oregon, in Glacier Bay National Park, in Muir Inlet, Alaska, and in other areas have reported behavioral disturbance and reproductive disruption and depression in a wide variety of marine species. These effects include birds fleeing nesting sites leaving chicks and eggs exposed to weather and predators; orcas and minke whales changing swimming speed and direction; and hauled-out harbor seals crushing and abandoning pups when scrambling back into the water (see review in Dornbusch & Co. 1994).”  Click Here

Christopher Solomon, Leaving Only Footsteps? Think Again  Feb. 2015  This very recent, easy-to-read New York Times article discusses the impact human activity (including birding and hiking!) has on all kinds of wildlife.  Solomon says, “Birds get ruffled, too. Researchers who studied trails around Boulder, Colo., found that populations of several species of songbirds, including pygmy nuthatches and Western meadowlarks, were lowest near trails. ‘There’s something about the presence of humans and their pets when they go on hikes that causes a bit of a ‘death zone’ of 100 meters on either side of a trail,’said Prof. Rick Knight of Colorado State University. Running, canoeing, cycling and similar activities negatively affected birds in nearly 90 percent of 69 studies that researchers reviewed in 2011. Reductions were seen in the number of nests built, eggs laid and chicks hatched or fledged.”  Click Here

National Audubon Society Climate Change Report: 314 Bird Species on the Brink   In its 2014 September-October issue, the Audubon Society published a groundbreaking study on the impact of climate change on birds.  Audubon scientists  used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change. The work defines the climate conditions birds need to survive, then maps where those conditions will be found in the future as the Earth’s climate responds to increased greenhouse gases. Audubon says it is the  broadest and most detailed study of its kind.  The report provides a regional break down of  the birds threatened by habitat loss.  According to this report, water birds in California that will suffer severe loss of habitat include some of our beloved birds on the San Lorenzo River.  These include  the Common Merganser, Hooded Merganser, Eared Grebe, Ring-necked Duck and Black-crowned Night-heron.  Click Here

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