Overview

Brief Summary

The Boat-tailed Grackle (Quiscalus major), a large blackbird of the southeastern United States, was not distinguished from the Great-tailed Grackle (Quiscalus mexicanus) until the 1970s, but the two forms overlap on the coasts of Texas and Louisiana without interbreeding. The Boat-tailed Grackle is generally more closely associated with water, such as around marshes and beaches, although in Florida it may be found inland. These birds eat a range of foods, mainly taken from water, such as aquatic insects, snails, crayfish, crabs, tadpoles, frogs, and small fish, but also including terrestrial insects and the eggs and young of other birds. During some seasons, seeds and grains are an important component of the diet. Nesting is in colonies, generally near water. These birds are often very common within their range, which in recent decades has extended northward along the Atlantic coast to Long Island (New York, U.S.A.). The distribution extends southward through peninsular Florida and west along the Gulf Coast to southeastern Texas. There is generally little movement between seasons, although a few northern breeders may move south in the fall. The Boat-tailed Grackle is one of only about a dozen bird species that are endemic to the United States (i.e., found nowhere else in the world). (Kaufman 1996; AOU 1998)

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The Boat-tailed Grackle (Quiscalus major) was not distinguished from the Great-tailed Grackle (Quiscalus mexicanus) until the 1970s, but the two forms overlap on the coasts of Texas and Louisiana without interbreeding. The Boat-tailed Grackle is generally more closely associated with water, such as marshes and beaches, although in Florida it may be found inland. These birds eat a range of foods, mainly taken from water, such as aquatic insects, snails, crayfish, crabs, tadpoles, frogs, and small fish, but also including terrestrial insects and the eggs and young of other birds. During some seasons, seeds and grains are an important component of the diet. Nesting is in colonies, generally near water. These birds are often very common within their range, which has extended northward along the Atlantic coast to Long Island (New York, U.S.A.) in recent decades. The distribution extends southward through peninsular Florida and west along the Gulf Coast to southeastern Texas. There is generally little movement between seasons, although a few northern breeders may move south in the fall. (Kaufman 1996; AOU 1998)

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Distribution

Global Range: RESIDENT: along Atlantic coast from Long Island and New Jersey south, throughout peninsular Florida, and west along Gulf coast to southeastern Texas (AOU 1983).

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Range Description

This species has a large range, with an estimated global Extent of Occurrence of 200,000 km. It has a large global population estimated to be 3,700,000 individuals (Rich et al. 2003). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

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endemic to a single nation

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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Physical Description

Size

Length: 42 cm

Weight: 214 grams

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Ecology

Habitat

Habitat and Ecology

Systems
  • Terrestrial
  • Freshwater
  • Marine
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Comments: Coastal salt marshes and barrier and sea islands, around ponds and streams (Florida peninsula), farmland, towns and cities. BREEDING: Nests generally near or over water, in willows, cattails, sawgrass, bulrushes; also up to 25 m in trees. See Dunham (1990) for information on nest-site selection in Florida.

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Migration

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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Trophic Strategy

Comments: Eats various invertebrates, grain, some small vertebrates; forages on ground, mudflats, shallow water (Terres 1980).

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Associations

Known prey organisms

Quiscalus major preys on:
Gallinula chloropus

This list may not be complete but is based on published studies.
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Life History and Behavior

Life Expectancy

Lifespan, longevity, and ageing

Maximum longevity: 12.9 years (wild) Observations: Considering the longevity of similar species, the maximum longevity of these animals could be significantly underestimated.
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Reproduction

Clutch size 1-5 (usually 2-3 in FL, Bancroft 1986). Two, some- times 3 broods/yr. Incubation 13-14 days, by female. Young tended by female, leave nest at 20-23 days. Nesting success varies greatly among localities & yrs. Usually colonial.

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Molecular Biology and Genetics

Molecular Biology

Barcode data: Quiscalus major

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 7 barcode sequences available from BOLD and GenBank.

Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.

See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

GGTGCATGAGCCGGGATAGTAGGTACCGCCCTA---AGCCTCCTAATTCGAGCAGAACTAGGCCAACCTGGAGCCCTTCTAGGAGAC---GACCAAGTCTACAACGTAGTTGTCACGGCCCATGCTTTCGTAATAATCTTCTTCATAGTCATACCAATCATAATCGGAGGATTCGGGAACTGACTAGTCCCCCTAATA---ATCGGGGCCCCAGACATAGCATTCCCACGAATAAACAACATGAGCTTCTGACTACTTCCCCCATCCTTCCTCCTCCTTCTAGCATCTTCCACAGTTGAAGCAGGTGCGGGTACAGGATGAACAGTATACCCCCCACTAGCAGGTAACCTAGCCCACGCCGGAGCTTCAGTCGACCTT---GCAATCTTCTCCCTACACCTAGCCGGTATCTCTTCAATCCTAGGAGCAATCAACTTCATTACAACAGCAATCAACATGAAACCCCCTGCCCTATCACAATACCAAACCCCCTTATTCGTTTGATCCGTACTAATCACCGCAGTACTACTACTCCTATCTCTTCCAGTTCTAGCCGCA---GGCATCACAATGCTTCTCACAGACCGCAACCTTAACACCACATTCTTTGACCCTGCCGGAGGAGGAGACCCA---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------GT
-- end --

Download FASTA File

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Statistics of barcoding coverage: Quiscalus major

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 7
Specimens with Barcodes: 8
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2015

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History
  • 2012
    Least Concern (LC)
  • Least Concern (LC)
  • Least Concern (LC)
  • Least Concern (LC)
  • Lower Risk/least concern (LR/lc)
  • Lower Risk/least concern (LR/lc)
  • Lower Risk/least concern (LR/lc)
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