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A Day at the Concord Marshes Important Bird Area ? the search for Tricolored Blackbirds
-account by Mike Perlmutter

Balmy and bright, conditions on this mid February day seemed auspicious for birding, although Mt. Diablo Audubon member Mike Robertson and I would need some extra luck for our task of the day: to find and census rare Tricolored Blackbirds along the Concord shoreline.  This survey, coordinated by Dr. Bob Meese, a Tricolored Blackbird researcher from UC Davis, under contract with CA Fish and Game and US Fish & Wildlife, was an attempt to identify evening roosts of Tricolored Blackbirds.

The Tricolored Blackbird is a Bird Species of Special Concern in California, and is one of three priority conservation species for Audubon California (the other two being California Condor and Western Snowy Plover).  Tricolored Blackbird also bears the unfavorable distinction of inclusion on the Audubon Watchlist (red-listed in California and yellow-listed nationwide).  These distinctions call attention to conservation of threatened, declining, or even state-extirpated species that may not receive protections under state and/or federal endangered species laws.

California supports 99% of the world?s estimated 250,000-300,000 Tricolored Blackbirds.  The species nests colonially, leaving large portions of the population vulnerable to localized disturbance and sudden land use changes.  Indeed, loss of wetland habitat has shifted nesting sites to agricultural fields, where massive nest failure can result if crop harvest precedes fledging of chicks.  Nest failure of large colonies can prove devastating to the long-term recovery of Tricolored Blackbirds.  Last year this real threat was narrowly abated on a 13 acre wheat field where southern California?s largest colony was breeding.  Audubon California and the San Bernardino Audubon Society paid the field?s owner to delay harvest by 30 days, allowing the Tricolored Blackbirds to complete their nesting cycle.  One year later, Audubon California is gearing up to conduct a statewide Tricolored Blackbird census on April 25-27, to come up with a contemporary population estimate for the species.  Today?s smaller survey will help further understand population and distribution patterns for this species.

Mike Robertson and I began our search in the mid-afternoon allowing for time to scan various wetlands along the Martinez and Concord shoreline.  These wetlands in part make up the Concord Marshes Important Bird Area and were once part of a sprawling network of sinewy sloughs, creeks, and marshes draining the watersheds and highlands of Diablo and Contra Costa ridges into the Carquinez Straits and Suisun Bay along the city shores of Martinez, Concord, and Pittsburg.  Now these wetlands are scattered in patchy distribution, dissected and disconnected from each other by roads, railways, neighborhoods, landfills, and industry.  Mike?s decade?s old fishing map of the area depicted many historic creeks long since channelized and sent underground in culverts and pipes, removed from light and life.  The wetlands that remain, while scattered, and tattered, are perhaps more important than ever, serving as a last refuge for biodiversity and providing other key ecological services such as water purification, and carbon sequestration.

Mike and I visited Martinez Regional Shoreline, and McNabney, Shell, and McVicar Marshes.  Scanning the shores, we focused on stands of cattails and reeds.  The wind floated fluffy cattail seeds across the marshes.  Black movements in the reeds drew our focus, but we did not see Tricolored Blackbirds, but rather blackbirds of three other sorts: Brewer?s and Red-winged Blackbirds, as well as Great-tailed Grackles.  Our next stop was the water treatment plant, whose sewage aerators were indeed teaming with blackbirds, but Red-winged only.

Driving through the network of industry, construction, and roadworks, we can make out wetlands in the distance, inaccessible through the modern concrete jungle.  As the daylight fades we make our way east along Waterfront Road until we reach an imposing security gate checkpoint at the base of the Tesoro oil refinery.  A testament to modern chemistry and plumbing, the plant is an impressive and complicated construction of pipes, cisterns and smokestacks.  The plant?s impacts to air quality however, were immediately palpable: the air stiflingly thick with petrochemical pollution.  California Proposition 65 signs warned of carcinogenic chemical exposure on site although the security guards stationed in the open air took no visible precaution.

After obtaining permits from the security guards we made our way into the heart of the plant on our way to the wetlands beyond.  We soon left industry behind us and were back amid the serenity of Pt. Edith Wildlife Area, a 760 acre marsh bordering Suisun Bay to the north, and the gated wetlands of the Concord Naval Weapons Station to the east.  Away from the oil refinery, the air quality was noticeably improved.  Mike and I drove the short distance of the road and scanned for Tricolored Blackbirds.  Reeds and cattails growing on both sides of the marsh made it hard to see far into the wetlands so we hopped up on the tailgate of Mike?s truck in order to improve our vantage point.

All was quiet on the marsh.

As light descended and shadows grew longer the marsh became increasingly active.  Isolated calls of rails beckoned from the reeds, Pacific chorus frog calls swelled en mass, and then out of the sky came the lazy lilt of the undulating flight-pattern of blackbirds.  Utility wires and poles, and tall shrubs vacant moments before, were now covered by hundreds of blackbirds.  The sharp glint of yellow in the eye marked many of these as Brewer?s Blackbirds.  Then came the chirps, trills, whirs, multiphonic whistles and clicks sounding so much like Red-winged Blackbirds.  We strained in vain to see the blazing red shoulder patches of the Red-winged Blackbirds.  We scrutinized the flock, studying each individual as we scanned down the power lines and on top of the shrubs.  There amongst the numerous Brewer?s Blackbirds, a few blackbirds stood out.  Adorned with distinctive white epaulets, the Tricolored Blackbirds, outnumbered 200 to 1 by the Brewer?s, stood out amongst the Brewer?s Blackbirds like army generals amongst mere privates.

Activity continued to pick up, now flocks were coming in from seemingly all directions.  Mike and I split up to better cover the area as sunlight waned and the winds picked up.  Within a half hour all the blackbirds had settled down, many moving out of view and deeper into the marsh to retire for the evening.  In that last flurry of crepuscular activity we observed 20 Tricolored Blackbirds.

Satisfied by both the strong finish and a generally good day of birding in the Concord Marshes Important Bird Area, Mike and I packed up, and like blackbirds, headed home for the night.


Volunteers are needed for Audubon California?s 2008 statewide Tricolored Blackbird survey.  The colony locations and numbers of Tricolored  Blackbirds change from year to year, making it impossible to track  without the help of volunteers across the state. The survey will take  place over one full day that is convenient for you between April 25th  and 27th, 2008. Additional days of survey following this will also be  welcomed and of great value. If you are interested in participating, please contact Rodd Kelsey (530) 795-0660 or rkelsey at audubon.org.


Mike Perlmutter
Bay Area Conservation Coordinator
Audubon California
4225 Hollis Street
Emeryville, CA 94608
Tel: 510-601-1866 ext. 231
Fax: 510-601-1954
MPerlmutter at audubon.org