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Fish Crow

Corvus ossifragus

Summary 2

The Fish Crow (Corvus ossifragus) is a species of crow that is associated with wetland habitats in the eastern and southeastern United States.

Taxon biology 3

The Fish Crow (Corvus ossifragus) is year-round resident locally from New York and Massachusetts south along the Atlantic-Gulf Coast to southern Florida and west to southern Texas, as well as inland along major river systems. It is very common in parts of its range. Fish Crows are found around tidewater marshes, low valleys along eastern river systems, and in Baldcypress (Taxodium) swamps; in recent decades, the interior range has expanded and the northern boundary of the range has extended northward. Although in most parts of its range it is a permanent resident, in winter Fish Crows withdraw from some parts of their inland range. In the winter, Fish Crows are often seen in mixed flocks with American Crows, when they may also be found on farmland, in towns, and around garbage dumps. The Fish Crow is one of only about a dozen bird species that are endemic to the United States (i.e., found nowhere else in the world).

The Fish Crow closely resembles the American Crow (Corvus brachyrhynchos), but is smaller overall and has a smaller bill, smaller feet, and shorter legs, as well as more pointed wings and a faster wingbeat. However, it is best distinguished by its quite different common call, a nasal two-note call with the second note lower in pitch (however, juvenile and sometimes adult American Crows produce similar calls).

Fish Crows may feed on an extraordinary range of foods, including carrion, crustaceans, insects, berries, seeds, nuts, bird eggs, turtle eggs, and human garbage. They generally forage in flocks, mainly by walking, especially along the shore or in very shallow water. They may drop mollusks from the air to break open their shells. In colonies of herons and other waterbirds, if the nesting adults are frightened off their nests, Fish Crows may feast on their eggs.

Fish Crows often nest in loose colonies of a few pairs. Courtship may involve the male and female flying close together in a gliding display flight. The nest is placed in an upright fork of a tree or shrub. The nest may be placed very low at coastal sites or quite high in deciduous trees in inland swamps (1 to 21 m above the ground or even higher) The nest (which is probably built by both sexes) is a bulky platform of sticks and strips of bark lined with softer materials such as grass,rootlets, hair, feathers, paper, pine needles, and even manure. The female lays 4 to 5 dull blue-green to gray-green eggs blotched with brown and gray. Incubation is by the female (possibly assisted by the male) for 16 to 18 days. Nestlings are probably fed by both parents. The age at which young leave the nest is uncertain, but is probably around 3 to 4 weeks.

(Kaufman 1996; AOU 1998; Dunn and Alderfer 2011)

Habitat 4

Comments: Beaches, bays, lagoons, inlets, swamps, near marshes, and, less frequently, deciduous or coniferous woodland. In inland situations, primarily in baldcypress swamps and along major watercourses; also garbage dumps and towns (McNair 1989). Nests in tree, usually high, but sometimes as low as 2 m (Harrison 1978).

Habitat and ecology 5

Systems

  • Terrestrial
  • Freshwater
  • Marine

Iucn red list assessment 6


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

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 very 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
  • 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)

Sources and Credits

  1. (c) Tom Wicker, some rights reserved (CC BY-NC-ND), http://www.flickr.com/photos/49058621@N05/4608376325
  2. Adapted by Amanda Carrillo-Perez from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Corvus_ossifragus
  3. Adapted by Amanda Carrillo-Perez from a work by (c) Leo Shapiro, some rights reserved (CC BY), http://eol.org/data_objects/18624473
  4. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28846889
  5. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34398165
  6. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34398163

More Info

Range Map

(c) NatureServe, some rights reserved (CC-BY-NC)

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