ITIS Basic Information
Common Name: Tricolored Blackbird
Scientific Name: Agelaius tricolor
Species Code: AGETRI
Management Category: SL (species at risk of loss)
Occurrence Map

Historically present
Currently present
Currently not detected
Table of Occurrences
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Species Information

MSP Species Background

Goals and Objectives

Goal: Protect, enhance, and restore Tricolored blackbird occupied and historically occupied habitat to create resilient, self-sustaining populations that provide for persistence over the long-term (>100 years).

regional NFO 2017, 2018 SL
MGT-IMP-IEX AGETRI-1

Management units: 3, 4, 5, 6, 9, 10, 11

From 2017-2018, support the existing efforts to restore the El Monte ponds and any other on-going habitat restoration projects for the benefit of nesting tricolored blackbird. This objective to be incorporated into the Tricolored Blackbird Management Plan after 2018.

Action Statement Action status Projects
IMP-1 Submit project metadata, data, and annual reports documenting project methods and results to the MSP Web Portal. Available for implementation
Criteria Deadline year
Restoration of El Monte ponds implemented for Tricolored Blackbird 2021
regional NFO 2017, 2018, 2019, 2020, 2021 SL
MON-RSUP-SPEC AGETRI-2

Management units: 3, 4, 5, 6, 9, 10, 11

From 2017 to 2021, support statewide survey efforts for Tricolored blackbird held every 3 years.

Action Statement Action status Projects
RSUP-1 Submit monitoring data and management recommendations to MSP web portal available for implementation
Criteria Deadline year
Participate in Surveys every 3 Years 2021
local NFO 2017, 2018, 2019, 2020, 2021 SL
MON-IMP-IMG AGETRI-3

Management units: 3, 4, 5, 6, 9, 10, 11

Beginning in 2017, annually inspect suitable nesting habitat at current and historically occupied sites (see occurrence table) to determine management needs (including need for additional water) taking care not to disturb nesting tricolored blackbirds, and use a regional IMG monitoring protocol to collect covariate data on human activities and other threats to determine management needs.

Action Statement Action status Projects
IMP-1 Conduct regional IMG monitoring protocol surveys to determine management needs (including need for additonal water) taking care not to disturb nesting tricolored blackbirds, available for implementation Tricolored Blackbird (Agelaius tricolor) Surveys
IMP-2 Based upon threat evaluation, determine if routine management or more intensive management is warranted. available for implementation
IMP-3 Submit monitoring data and management recommendations to MSP web portal available for implementation Tricolored Blackbird (Agelaius tricolor) Surveys
Criteria Deadline year
Annual IMG monitoring of Tricolored Blackbird completed 2021
local NFO 2017, 2018, 2019, 2020, 2021 SL
MGT-IMP-IMG AGETRI-4

Management units: 3, 4, 5, 6, 9, 10, 11

Beginning in 2017, conduct routine management actions identified through the IMG regional protocol monitoring.

Action Statement Action status Projects
IMP-1 Perform routine management activities such as protecting occurrences from disturbance through fencing, signage, and enforcement and adding additonal water to ponded sites. available for implementation
IMP-2 Submit project metadata and management data to the MSP web portal. available for implementation
Criteria Deadline year
Routine Management Completed as Needed Based Upon Monitoring Recommendations 2021
regional NFO 2018 SL
MGT-PRP-MGTPL AGETRI-5

Management units: 3, 4, 5, 6, 9, 10, 11

In 2018, prepare a management plan for tricolored blackbird that prioritizes management actions to protect nesting sites from disturbance and enhances habitat using data from annual IMG monitoring.

Action Statement Action status Projects
PRP-1 Prioritize management actions, focusing on reducing threats and expanding occurrences in areas most likely to remain viable over the long-term in the context of future land development. Available for implementation
PRP-2 Develop an implementation plan for tricolored blackbird that prioritizes management actions for the next five years. Available for implementation
PRP-3 Submit management plan to MSP web portal Available for implementation
Criteria Deadline year
Management Plan for Tricolored Blackbird prepared by 2019 2021
regional and/or local NFO 2019, 2020, 2021 SL
MGT-IMP-MGTPL AGETRI-6

Management units: 3, 4, 5, 6, 9, 10, 11

Beginning in 2019, implement the highest priority management actions for tricolored blackbird on Conserved Lands.

Action Statement Action status Projects
IMP-1 Management actions to be determined by the management plan. waiting for precedent action
IMP-2 Submit project data and management actions to MSP web portal waiting for precedent action
Criteria Deadline year
Management actions implemented for Tricolored Blackbird 2021
regional and/or local NFO 2019, 2020, 2021 SL
MON-IMP-MGTPL AGETRI-7

Management units: 3, 4, 5, 6, 9, 10, 11

Beginning in 2019, monitor the effectiveness of management actions implemented for tricolored blackbird on Conserved Lands

Action Statement Action status Projects
IMP-1 Submit monitoring data and reports to MSP web portal waiting for precedent action
Criteria Deadline year
Monitoring Completed within one year of management actions and Report Submitted 2021
Tricolored Blackbird (Agelaius tricolor) Surveys
Tricolored blackbird is a state-listed endangered species that has declined dramatically in southern California. Once abundant and widespread in San Diego County, there are few known breeding populations remaining at marshes on Conserved Lands. AECOM biologists surveyed for tricolored blackbirds in spring 2021 at historic and recently documented breeding habitats and at potentially suitable habitats. Surveys were to determine if tricolored blackbirds are present during the breeding season and to estimate population size and breeding status. AECOM biologists used a protocol developed by SDMMP to evaluate habitat quality and threats at each suitable habitat site, even those without tricolored blackbirds. These data , and data from subsequent yearly surveys, will be provided to SDMMP to develop management recommendations for tricolored blackbird. Tricolored blackbirds will be surveyed for annually.

Current Distribution Rangewide

Native to California. Small nesting colonies found in Oregon, Washington, Nevada, and coastal Baja California [1;2]. Common throughout Central Valley and in coastal districts from Sonoma County south [3]. Winter in San Francisco Bay Delta, along central California coast, San Joaquin Valley, and southern California [4].

Known Populations in San Diego County

Concentrated in two areas: north-central San Diego county from Dameron Valley and Oak Grove south to Ramona and Santa Ysabel, and the Campo Plateau from Potrero to Jacumba. In mid 1800s, one of most abundant bird species near San Diego, this species has declined significantly to a small portion of former range in the County [5].

List Status

SSC, Currently in evaluation process of State and Federal listing of Threatened and/or Endangered

Habitat Affinities

Most nesting colonies are in cattail marshes but may also be in blackberry thickets or stands of black mustard [5]. Basic requirements for breeding sites are open accessible water, a secure substrate for nesting that may include flooded or thorny or spiny vegetation, and suitable nearby foraging areas that provide adequate food sources within a few kilometers of the nesting colony [6, cited from 1]. During winter, they are associated with open rangeland. Found in lowland areas, typically less than 1000 m elevation. Open water within 500 m is a requirement for colony settlement [7]. Form “mega-colonies” in grain fields (silage), usually associated with dairy farms [1;8;9].

Taxonomy and Genetics

Diverged over 3 million years ago from its nearest relative and most common bird in North America, the Red-winged Blackbird (Agelaius phoeniceus) [10 cited from 8]. Differs from Red-Winged Blackbird because of breeding ecology; tricolored blackbirds are colonial while red-winged blackbirds defend individual territories [11].

Seasonal Activity

Flocks are nomadic during fall when seeking food [5].

Life History/Reproduction

Colonial species [1;11;12] with polygynous mating system [3;8;13]. Breeding season mid-April into late July; Clutch size usually 3-4 eggs, range 2-6 [12;13 cited from both 3;14] . Nest building takes approximately 4 days with egg laying occurring as early as 2 days after nest initiation [15 cited from 11]. One egg laid per day; Incubation lasts about 11 days; altricial young tended by female or by both parents [3;7;15 and 16 cited from 11]. Young leave nest at about 13 days [3]. May nest 2 or more times per year [11].

Diet and Foraging

Most important prey for adults provisioning nestlings include: Coleopterans (beetles), Orthopterans (grasshoppers, locusts), Hemipterans (true bugs), other larval insects, and Arachnids. Ideal foraging conditions are created when shallow flood irrigation, mowing, or grazing keeps the vegetation at optimal height (<15 cm) [1;8]. Animal matter makes up 91% of the food volume of nestlings and fledglings, 56% of the food volume of adult females, and 28% of the food volume of adult males [17]. Seed and cultivated grains are other major foods composing most of fall and winter diet. Forages on ground [3]. During breeding season, forages in nearby grassland, pastures, or agricultural fields; also forages readily in artificial habitats such as dairies, lawns, garbage dumps, and parking lots in nonbreeding season [5].

Dispersal

Year round resident in many areas but also move throughout the valleys and foothills of cismontane California and southern Oregon during breeding season [4]. Wintering populations move extensively throughout their range during the nonbreeding season [1]. In San Diego County, most of the population does not shift a great distance [5].

Threats

Primary threats include: direct loss and degradation of breeding and foraging habitats resulting from water diversions, large-scale agricultural and urban land conversions; nest predation; and loss of nests in silage due to the timing of harvests [1;8].

Literature Sources

[1] Beedy, E. C. 2008. Tricolored Blackbird. In California Bird Species of Special Concern, W. D. Shuford and T. Gardali, 437-443. Western Field Ornithologists, Camarillo, CA and California Department of Fish and Game, Sacramento, CA.

[2] Berg, E.C., J.P. Pollinger, and T.B. Smith. 2015. Population structure of the Tricolored Blackbird (Agelaius tricolor) in California: are northern and southern populations genetically distinct?. Report prepared for the California Department of Fish and Game, sacramento, California, and Audubon California, Emeryville, California.

[3] Granholm, S. Tricolored Blackbird. upd. 2008. Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California's Wildlife. Vol. I-III. California Department of Fish and Game, Sacramento, California.

[4] Hamilton III, W. J. 1998. Tricolored Blackbird itinerant breeding in California. Condor: 218-226.

[5] Unitt, P. 2004. San Diego County Bird atlas. Proc. San Diego Soc. Nat Hist. 39.

[6] Beedy, E.C. and W. J. Hamilton III. 1999. Tricolored Blackbird: Agelaius Tricolor. Birds of North America, Inc.

[7] Hamilton, W. J. 2004. Tricolored Blackbird (Agelaius tricolor). In The Riparian Bird Conservation Plan:a strategy for reversing the decline of riparian-associated birds in California. California Partners in Flight. Available from http://www.prbo.org/calpif/htmldocs/riparian_v-2.html. Accessed October 20, 2016.

[8] Tricolored Blackbird Working Group. 2009. Conservation Plan for the Tricolored Blackbird (Agelaius tricolor) 2.0 Update. Susan Kester (ed.) Sustainable Conservation. San Francisco, CA.

[9] Kelsey, R. 2008. Results of the Tricolored Blackbird 2008 Census. Audubon California.

[10] Yasukawa, K. and W. A. Searcy. 1995. Red-winged blackbird (Agelaius phoeniceus). In A. Poole and F. Gill (eds.), The Birds of North America, No. 184. Philadelphia, PA: Academy of Natural Sciences and Washington, DC: American Ornithologists Union.

[11] East Contra Costa County HCP/NCCP. 2006. Tricolored Blackbird Species Account.

[12] Campbell, K. F. Tricolored Blackbird:Agelaius tricolor. Pepared for the Bureau of Land Manangement.

[13] Terres, J. K. 1980. Audubon Society Encyclopedia of North American Birds. Knopf; Distributed by Random House.

[14] Solano County Water Agency. 2012. Tricolored Blackbird Species Account. Public Draft Solano HCP

[15] Payne, R.B. 1969. Breeding seasons and reproductive physiology of tricolored blackbirds and redwinged blackbirds. University of California Press.

[16] Hamilton III, W. J., L. Cook, and R. Grey. 1995. Tricolored blackbird project 1994. Report prepared for the US Fish and Wildlife Service, Portland, Oregon, and California Department of Fish and Game, Sacramento, California.

[17] Skorupa, J. P., R. L. Hothem, and R. W. Dehaven. 1980. Foods of breeding tricolored blackbirds in agricultural areas of Merced County, California. The Condor82 (4): 465-467.