Tricolored Blackbird
Encyclopedia
The Tricolored or Tricoloured Blackbird, Agelaius tricolor, is a passerine
bird
of the family Icterid
ae. Its range is limited to the coastal areas of the Pacific
coast of North America, from Northern California
in the U.S. (with occasional strays into Oregon
), to upper Baja California
in Mexico.
This highly social and gregarious bird forms the largest colonies of any North American landbird, with a single breeding colony often consisting of tens of thousands of birds.
The common name is taken from the male bird's distinctive white stripes on bottom of their red shoulder patches, or "epaulets", which are visible when the bird is flying or displaying.
Despite the similar names, this bird is not related to the Old World Common Blackbird, which is a thrush
(Turdidae).
The species' call is a mite more nasal than that of the Red-Wing's - a nasal kip and a sharp check. The male's song is a garbled on-ke-kaaangh.
The bird migrates south during the colder seasons to Mexico and back to northern California during the warmer seasons.
By 1991, the Tricolor's breeding population had fallen to approximately thirty five thousand adults. This prompted a petition submitted by the Yolo chapter of the National Audubon Society to the California Fish and Game Commission. The petition brought the Tricolored Blackbird under consideration for endangered classification. The classification was granted until the breeding season in 1992. It was then that researchers discovered a population exceeding three hundred thousand adults. A petition to withdraw the endangered classification was submitted and accepted. Conservation measures were supposed to be developed and implemented to avoid a future decline as seen before. These measures were developed, but only very limited progress was made in preventing the future decline of the Tricolored Blackbird. Interested groups started reconvening shortly after the year 2000. Managing groups found startling results when conducting population research.
In 2006 the Tricolored Blackbird was classified as Endangered by BirdLife International
. Like the extinct Passenger Pigeon
, the colonial nature of the Tricolored Blackbird makes it particularly vulnerable to extinction. Native grassland
s once used for nesting and feeding have been lost to urban and agricultural development. Birds adapted to nesting in agricultural fields have been disturbed by harvesting during the breeding season. Once the Tricolored Blackbird was placed back on the Endangered Species list, it officially became a concern both regionally and nationally.
The U.S. Fish and Wildlife Service maintained the following "Primary conservation priorities for Tricolor habitat conservation and management" (The Tricolored Blackbird Working Group, 2007):
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of the family Icterid
Icterid
The Icterids are a group of small to medium-sized, often colorful passerine birds restricted to the New World. Most species have black as a predominant plumage color, often enlivened by yellow, orange or red. The family is extremely varied in size, shape, behavior and coloration...
ae. Its range is limited to the coastal areas of the Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coast of North America, from Northern California
Northern California
Northern California is the northern portion of the U.S. state of California. The San Francisco Bay Area , and Sacramento as well as its metropolitan area are the main population centers...
in the U.S. (with occasional strays into Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
), to upper Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
in Mexico.
This highly social and gregarious bird forms the largest colonies of any North American landbird, with a single breeding colony often consisting of tens of thousands of birds.
The common name is taken from the male bird's distinctive white stripes on bottom of their red shoulder patches, or "epaulets", which are visible when the bird is flying or displaying.
Despite the similar names, this bird is not related to the Old World Common Blackbird, which is a thrush
Thrush (bird)
The thrushes, family Turdidae, are a group of passerine birds that occur worldwide.-Characteristics:Thrushes are plump, soft-plumaged, small to medium-sized birds, inhabiting wooded areas, and often feed on the ground or eat small fruit. The smallest thrush may be the Forest Rock-thrush, at and...
(Turdidae).
The species' call is a mite more nasal than that of the Red-Wing's - a nasal kip and a sharp check. The male's song is a garbled on-ke-kaaangh.
The bird migrates south during the colder seasons to Mexico and back to northern California during the warmer seasons.
Endangered status
In 1990 the Department of Fish and Game (DFG) of California, based on significant decline in population numbers documented in the 1980's, added the Tricolored Blackbird to the published list of "Bird Species of Special Concern". This classification is an "administrative designation intended to alert biologists, land managers and others to a species declining status and encourages them to provide additional management considerations". At this time the Tricolored was added to the U.S. Fish and Wildlife Service (USFWS) list of Birds of Conservation Concern.By 1991, the Tricolor's breeding population had fallen to approximately thirty five thousand adults. This prompted a petition submitted by the Yolo chapter of the National Audubon Society to the California Fish and Game Commission. The petition brought the Tricolored Blackbird under consideration for endangered classification. The classification was granted until the breeding season in 1992. It was then that researchers discovered a population exceeding three hundred thousand adults. A petition to withdraw the endangered classification was submitted and accepted. Conservation measures were supposed to be developed and implemented to avoid a future decline as seen before. These measures were developed, but only very limited progress was made in preventing the future decline of the Tricolored Blackbird. Interested groups started reconvening shortly after the year 2000. Managing groups found startling results when conducting population research.
In 2006 the Tricolored Blackbird was classified as Endangered by BirdLife International
BirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
. Like the extinct Passenger Pigeon
Passenger Pigeon
The Passenger Pigeon or Wild Pigeon was a bird, now extinct, that existed in North America and lived in enormous migratory flocks until the early 20th century...
, the colonial nature of the Tricolored Blackbird makes it particularly vulnerable to extinction. Native grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s once used for nesting and feeding have been lost to urban and agricultural development. Birds adapted to nesting in agricultural fields have been disturbed by harvesting during the breeding season. Once the Tricolored Blackbird was placed back on the Endangered Species list, it officially became a concern both regionally and nationally.
The U.S. Fish and Wildlife Service maintained the following "Primary conservation priorities for Tricolor habitat conservation and management" (The Tricolored Blackbird Working Group, 2007):
- Maintain, enhance, and protect existing habitat suitable for nesting, foraging, and wintering activities;
- Create and restore additional protected breeding habitats to support nesting and foraging;
- Identify mechanisms for protecting nesting and foraging habitats;
- To the extent allowable by law, survey private lands and identify largest and most vulnerable colonies;
- Encourage private landowners to protect active breeding colonies; and
- Encourage and enhance active breeding colonies on public lands.
Book
- Beedy, E. C., and W. J. Hamilton III. 1999. Tricolored Blackbird (Agelaius tricolor). In The Birds of North America, No. 423 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Thesis
- Orians GH. Ph.D. (1961). THE ECOLOGY OF SOCIAL SYSTEMS IN THE RED-WINGED BLACKBIRD (AGELAIUS PHOENICEUS) AND THE TRICOLORED BLACKBIRD (AGELAIUS TRICOLOR). University of California, Berkeley, United States—California.
Articles
- (2003). Emergency protection sought for tricolored blackbird. J Wildl Rehabil. vol 26, no 3. p. 36-36.
- Academy of Natural Sciences of P. (1999). Tricolored blackbird: Agelaius tricolor. Birds of North America. vol 0, no 423. p. 1-23.
- Cook LF & Toft CA. (2005). Dynamics of extinction: population decline in the colonially nesting Tricolored Blackbird Agelaius tricolor. Bird Conservation International. vol 15, no 1. p. 73-88.
- Crase FT & De Haven RW. (1977). Food of Nestling Tricolored Blackbirds. Condor. vol 79, no 2. p. 265-269.
- Crase FT & Dehaven RW. (1976). Selected Bibliography on the Food Habits of North American Blackbirds. U S Fish & Wildlife Service Special Scientific Report Wildlife. vol 192, p. 1-20.
- Crase FT & Dehaven RW. (1978). Food Selection by 5 Sympatric California USA Blackbird Species. California Fish & Game. vol 64, no 4. p. 255-267.
- De Haven RW, Crase FT & Woronecki PP. (1975). Movements of Tricolored Blackbirds Banded in the Central Valley of California 1965-1972. Bird Banding. vol 46, no 3. p. 220-229.
- Dehaven RW, Crase FT & Miller MR. (1974). Aging Tri Colored Blackbirds by Cranial Ossification. Bird Banding. vol 45, no 2. p. 156-159.
- Dehaven RW, Crase FT & Woronecki PP. (1975). BREEDING STATUS OF TRICOLORED BLACKBIRD, 1969-1972. Calif Fish Game. vol 61, no 4. p. 166-180.
- Emlen JT. (1985). Morphological Correlates of Synchronized Nesting in Tricolored Blackbird Agelaius-Tricolor Colony. Auk. vol 102, no 4. p. 882-884.
- Hamilton WJ, III. (1998). Tricolored blackbird itinerant breeding in California. Condor. vol 100, no 2. p. 218-226.
- Holcomb LC. (1971). Nest Building and Egg Laying by Redwinged Blackbirds in Response to Artificial Manipulations. Auk. vol 88, no 1. p. 30-34.
- Kobayashi H. (1975). Absorption of Cerebro Spinal Fluid by Ependymal Cells of the Median Eminence. In Knigge, K M et al. (Ed) Brain-Endocrine Interaction Ii the Ventricular System in Neuroendocrine Mechanisms Symposium Shizuoka, Japan Oct 16-18, 1974 Ix+406p Illus S Karger: Basel, Switzerland; New York, NY, USa Isbn 3-8055-2176-6 109-122, 1975.
- Oota Y, Kobayashi H, Nishioka RS & Bern HA. (1974). Relationship between Neuro Secretory Axon and Ependymal Terminals on Capillary Walls in the Median Eminence of Several Vertebrates. Neuroendocrinology. vol 16, no 2. p. 127-136.
- Palmer TK. (1976). Pest Bird Damage Control in Cattle Feedlots the Integrated Systems Approach. Proceedings of the Vertebrate Pest Conference. vol 7, p. 17-21.
- Payne RB & Landolt M. (1970). Thyroid Histology of Tricolored Blackbirds Agelaius-Tricolor in the Annual Cycle Breeding and Molt. Condor. vol 72, no 4. p. 445-451.
- Powell GVN. (1974). Experimental Analysis of the Social Value of Flocking by Starlings Sturnus-Vulgaris in Relation to Predation and Foraging. Animal Behaviour. vol 22, no 2. p. 501-505.
- Rains MC, Mount JE & Larsen EW. (2004). Simulated changes in shallow groundwater and vegetation distributions under different reservoir operations scenarios. Ecol Appl. vol 14, no 1. p. 192-207.
- Schafer EWJ & Brunton RB. (1971). Chemicals as Bird Repellents 2 Promising Agents. Journal of Wildlife Management. vol 35, no 3. p. 569-572.
- Skorupa JP, Hothem RL & Dehaven RW. (1980). Foods of Breeding Tri Colored Blackbirds Agelaius-Tricolor in Agricultural Areas of Merced County California USA. Condor. vol 82, no 4. p. 465-467.
- Unitt P. (2004). Effect of plumage wear on the identification of female Red-winged and Tricolored Blackbirds. Western Birds. vol 35, no 4. p. 228-230.
- Vickers ML & Hanson RP. (1980). Experimental Infection and Serologic Survey for Selected Paramyxoviruses in Red-Winged Blackbirds Agelaius-Phoeniceus. Journal of Wildlife Diseases. vol 16, no 1. p. 125-130.
- http://www.fws.gov/migratorybirds/CurrentBirdIssues/Management/FocalSpecies/Plans/TCBL.pdf
External links
- Tricolored Blackbird Portal Information Center for the Environment, UCDavis
- Tricolored Blackbird photo gallery VIREO