Animal Diversity Web

Ge­o­graphic Range

The ge­o­graphic range of fish crows (Corvus os­sifra­gus) is lim­ited to the Nearc­tic range. Fish crows are na­tive to the east coast of the United States but have been found as far west as Ne­braska, Wyoming, Kansas and Iowa (Jor­gen­son et al., 2009). Their north­ern range ex­tends to Maine and their south­ern range ex­tends to Florida (Mc­Gowan, 2001).

The mi­gra­tory habits of fish crows have not been stud­ied in depth. How­ever, Hamel (1992) sug­gests that these crows uti­lize the coastal re­gions of their range in the win­ter. They move more to the in­land por­tions of their range dur­ing the breed­ing sea­son. (Hamel, 1992; Jones, 1990; Jor­gensen, et al., 2009; Mc­Gowan, 2001; Wells and Mc­Gowan, 1991)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Fish crows are most com­monly found in tem­per­ate forests near aquatic habi­tats. These habi­tats in­clude es­tu­ar­ies, rivers, lakes, brack­ish water, lakes, ponds, the coast, and other ri­par­ian bio­mes (el­e­va­tion 0 m). Fish crows are also found in marshes and swamps. These crows have been found in urban, sub­ur­ban, and agri­cul­tural areas. In the south­east­ern part of the United States, fish crows can be found dur­ing breed­ing sea­son in pine (Pinus) forests and in oak (Quer­cus)-hick­ory (Carya) forests, while in the win­ter sea­son they can be found in oak forests close to shore­lines and in Vir­ginia pines (Pinus vir­gini­ana). (Hamel, 1992; Mc­Gowan, 2001)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• forest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal
• brackish water

• Wetlands
• marsh
• swamp

• Other Habitat Features
• urban
• suburban
• agricultural
• riparian
• estuarine

• Range elevation

  0 (low) m

  0.00 (low) ft

Phys­i­cal De­scrip­tion

Fish crows are com­pletely black in col­oration, with adults hav­ing a green-pur­ple sheen on their plumage. The feath­ers on their wings and tails tend to age over time, fad­ing to grey on the tips. Their eyes are black, and their bills are glossy and short. Their legs are black and scaled on the an­te­rior side but smooth pos­te­ri­orly. The av­er­age basal meta­bolic rate is 0.85 kcal per sec­ond. On av­er­age, adult fish crows weigh 195 to 330 g. Body lengths range from 36 to 40 cm. Av­er­age wingspan is un­known.

Fish crows go through sev­eral de­vel­op­men­tal stages. When first hatched, chicks have a drab, brown down or yel­low patches with­out down. The in­sides of ju­ve­nile mouths are pink and their eyes are closed right after hatch­ing. The ju­ve­nile stage is char­ac­ter­ized by the com­ple­tion of the pre-ju­ve­nile molt. Ju­ve­nile plumage is black on the wings and tail, with the body and head feath­ers a dark brown - al­most black. Ju­ve­nile feath­ers are looser and fluffier than adult feath­ers. Their eyes darken to a gray color. Av­er­age size and length for hatch­ling and im­ma­ture fish crows is un­known.

Adult fish crows go through two molts through­out the year, the first from July through late Oc­to­ber and the sec­ond oc­cur­ring from late June through late July a year later. There are very few dif­fer­ences be­tween the two molts. The first molt is char­ac­ter­ized by worn out feath­ers and a bluer un­der­tone to the feath­ers. The sec­ond molt gives the feath­ers on the throat a more dis­tinct rough pat­tern.

While there are no dif­fer­ences in plumage color be­tween male and fe­male fish crows, there is a slight size dif­fer­ence be­tween the sexes. Male fish crows are slightly larger than the fe­male fish crows. The exact size dif­fer­ence has not been re­ported.

Fish crows are sim­i­lar to Amer­i­can crows (Corvus brachyrhyn­chos), but fish crows are smaller than Amer­i­can crows. Fish crows also have a unique call that sounds like a more nasal ver­sion of calls Amer­i­can crows make. When mak­ing these calls, the neck feath­ers of fish crows will fluff up. (Jor­gensen, et al., 2009; Laiolo and Rolando, 2003; Mc­Gowan, 2001; Poole, 1938)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  195 to 330 g

  6.87 to 11.63 oz

• Range length

  36 to 40 cm

  14.17 to 15.75 in

• Average wingspan

  unknown mm

  in

Re­pro­duc­tion

Fish crows breed sea­son­ally and are monog­a­mous dur­ing breed­ing sea­sons. Courtship dis­plays be­tween pairs are un­com­mon, al­though Mc­Gowan (2001) sum­ma­rized mat­ing ac­tiv­i­ties for these crows. Males may ini­ti­ate mat­ing in one of two ways – males ei­ther feed po­ten­tial mates or they some­how tap the beaks of fe­males. If fe­males are re­cep­tive, they ini­ti­ate a three-step process that in­volves stiff­en­ing their bod­ies, hun­ker­ing down, and spread­ing out the feath­ers on their tails. After mat­ing, pairs will sit close to­gether and some­times pluck at nearby twigs. Mc­Gowan also sum­ma­rized one in­ci­dent of a crow dis­play­ing as it car­ried ma­te­ri­als to the nest. It was de­scribed as a “but­ter­fly” flight pat­tern.

Fish crows have been ob­served build­ing nests in mid-April in New York and Vir­ginia, and in late March through mid-April in Florida. Both males and fe­males help build nests. Nests are built dur­ing the day, and gen­er­ally take 9 or more days to com­plete. Nests are not reused each sea­son and are typ­i­cally built close to the tops of trees. These nests are made out of sticks and twigs in a cup shape. The sticks used in fish crow nests have been ob­served to have a di­am­e­ter of 4 to 8 mm. Mud or dung is also used in the outer con­struc­tion of these nests. Inner lin­ings of nests have softer ma­te­ri­als, such as bark fibers, hair, and pine nee­dles. One nest in New York was ob­served to have outer di­men­sions of 50 cm by 37 cm, with inner di­men­sions of 12.5 cm by 12.5 cm (Mc­Gowan, 2001). (Mc­Gowan, 2001)

• Mating System
• monogamous

Fish crows breed once a year from late March to mid-June. These birds only have one brood per sea­son, and if dis­turbed early enough in the sea­son, they will re-nest. Fish crows lay 2 to 6 eggs per sea­son. Eggs are el­lip­ti­cal in shape and are roughly 37.8 mm long by 27.3 mm wide. Egg masses have not been recorded, but empty eggshells have been ob­served to weigh 0.882 g. The out­side tex­ture of eggs are slightly rough and glossy. They are pale blue-green with brown speck­ling.

Only fe­male fish crows in­cu­bate eggs, which take 16 to 19 days to hatch. Birth masses for young fish crows is cur­rently un­known. Young fish crows fledge 32 to 40 days after hatch­ing and are in­de­pen­dent about a month after fledg­ing. Both males and fe­males reach sex­ual ma­tu­rity at about 15 months of age. (Hamel, 1992; Har­ri­son, 1978; Head­strom, 1970; Mc­Gowan, 2001; Reese, 2015)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• oviparous

• Breeding interval

  Fish crows breed once a year

• Breeding season

  Late March through mid-June

• Range eggs per season

  2 to 6

• Average eggs per season

  4-5

• Range time to hatching

  16 to 19 days

• Average time to hatching

  18 days

• Range fledging age

  32 to 40 days

• Range time to independence

  62 to 70 days

• Range age at sexual or reproductive maturity (female)

  15 (low) months

• Range age at sexual or reproductive maturity (male)

  15 (low) months

Both male and fe­male fish crows help build nests. After lay­ing eggs, fe­male fish crows stay at their nests to brood and keep eggs warm while males for­age for food. Male fish crows also pro­tect the nest and fe­males from preda­tors. After eggs hatch, both fe­male and male fish crows help feed young, and male fish crows con­tinue to pro­tect young from preda­tors. Both par­ents teach young how to for­age and fly. This con­tin­ues until ju­ve­niles fledge and be­come in­de­pen­dent. (Mc­Gowan, 2001)

• Parental Investment
• altricial
• male parental care
• female parental care
• pre-fertilization
  • provisioning
  • protecting
    • male
• pre-hatching/birth
  • provisioning
    • male
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifes­pan/Longevity

Fish crows in the wild are known to live for 6 to 7 years on av­er­age, with the old­est recorded age being 14.5 years. Lifes­pan lim­i­ta­tions in the wild in­clude pre­da­tion (es­pe­cially nest preda­tors), hunt­ing, ex­po­sure, and col­li­sions with cars. They are kept in cap­tiv­ity for re­search pur­poses, but lifes­pans have not been re­ported. (Clapp, 1983; Mc­Gowan, 2001)

• Average lifespan
  Status: wild

  14.5 years

• Average lifespan
  Status: wild

  6-7 years

Be­hav­ior

Fish crows are ar­bo­real, liv­ing in trees near bod­ies of water. They move around mostly by fly­ing, but have been ob­served hop­ping around on the ground while for­ag­ing. Fish crows have mi­gra­tory pat­terns, but are not true mi­gra­tory birds. Fish crows move fur­ther in­land dur­ing warmer sea­sons and move back to­wards the shores dur­ing colder sea­sons. They are ac­tive dur­ing the day and also mi­grate dur­ing the day. Fish crows leave their over­win­ter­ing ter­ri­to­ries and search for breed­ing ter­ri­to­ries from March to April, and leave their breed­ing ter­ri­to­ries in Sep­tem­ber. Tim­ing dif­fers across their ge­o­graphic range.

Fish crows scratch their heads in­di­rectly, using their feet to push their wings for­ward to­wards their heads. They bathe by putting their chest in the water, then flap­ping their wings in the water. They then throw water onto their backs. Fish crows also bathe in the rain when pos­si­ble. These birds preen each other and their nestlings. Fish crows sun­bathe on the ground or in trees with their wings slightly ex­tended and their bills slightly agape.

Out­side of breed­ing sea­son, fish crows will roost to­gether in trees or marshes. These birds will also roost with other species of birds such as Amer­i­can crows (Corvus brachyrhyn­chos), great blue herons (Ardea hero­dias), great egrets (Ardea alba), snowy egrets (Egretta thula), lit­tle blue herons (Egretta caerulea), tri­col­ored herons (Egretta tri­color), and green herons (Bu­torides virescens). Fish crows also roost with gulls in order to steal their eggs.

Fish crows are ter­ri­to­r­ial when it comes to pro­tect­ing their nests. Like other crows, fish crows will peck at other birds or try to grab their legs. Fish crows will also pull at the tails of other birds. Fight­ing fish crows will some­times fall out of trees. They chase preda­tors away from nests by div­ing down at them. Mob­bing is a com­mon be­hav­ior in fish crows. Fish crows have a spe­cific threat pos­ture where they will lower their heads and spread out their wings while walk­ing side­ways to­wards their op­po­nent. Cer­tain fish crow calls also in­di­cate ag­gres­sion, such as ag­gres­sive rat­tle calls. After a fight, an ap­pease­ment dis­play by los­ing fish crows oc­curs. In this dis­play, they do beg­ging calls and lower their bod­ies.

Fish crows nest close to one an­other but are not a colo­nial species. These birds are so­cial but have no ob­served so­cial hi­er­ar­chies. Fish crows are most so­cial dur­ing non-breed­ing sea­son. When an alarm call is sounded, fish crows will flock to­gether to mob preda­tors. Young fish crows will play with ob­jects. Fish crows com­mu­ni­cate pri­mar­ily through calls, vo­cal­iz­ing through­out the day for dif­fer­ent rea­sons. They are more vocal dur­ing breed­ing sea­son, with more beg­ging calls being used by fe­males and young. Spe­cific calls are used to in­di­cate ter­ri­tory pro­tec­tion. Tac­tile com­mu­ni­ca­tion hap­pens dur­ing shows of ag­gres­sion (mob­bing be­hav­iors and fight­ing), breed­ing, and car­ing for young.

Re­pro­duc­tive be­hav­iors in­clude find­ing a mate, build­ing nests, mat­ing, and car­ing for young. Courtship dis­plays be­tween pairs are un­com­mon, but there was an in­ci­dent de­scribed by Mc­Gowan (2001) where a crow flew in a pat­tern sim­i­lar to a "but­ter­fly" while car­ry­ing ma­te­ri­als to the nest. Both males and fe­males build nests dur­ing the day, which take about 9 days to build on av­er­age. Males ini­ti­ate mat­ing by ei­ther feed­ing po­ten­tial mates or touch­ing their beaks. If fe­males are re­cep­tive they stiffen their bod­ies, bend down, and spread their tail feath­ers out. After mat­ing, pairs sit close to­gether and some­times pluck at nearby twigs. Males pri­mar­ily pro­tect the nests, young, and fe­males. After eggs hatch, males will bring food back to the nest for fe­males and young, and both fe­males and males will take care of fecal sacs pro­duced by young. Both males and fe­males help raise hatch­lings. (Hamel, 1992; Laiolo and Rolando, 2003; Mc­Gowan, 2001; Mon­tevec­chi, 1978; Reese, 2015; San­tis­te­ban, et al., 2002; Shields and Par­nell, 1986; Zerega, 1880)

• Key Behaviors
• arboreal
• flies
• glides
• diurnal
• motile
• migratory
• territorial
• social

Home Range

Home ranges for fish crows have not been re­ported, but Mc­Gowan (2001) states that these crows travel at least 500 m from their nests. They de­fend ter­ri­tory within a small range of their nests, but exact mea­sure­ments have not been re­ported. (Mc­Gowan, 2001)

Com­mu­ni­ca­tion and Per­cep­tion

Fish crows have a repet­i­tive set of vo­cal­iza­tions. Fe­male fish crows have a higher pitched call than males. They do not use songs to com­mu­ni­cate but have a very dis­tinct call. This is a more nasal ver­sion of calls Amer­i­can crows (Corvus brachyrhyn­chos) make, de­scribed as "uh-uh" or "cawk." Fish crows vo­cal­ize daily and through­out the day.

Mc­Gowan (2001) states that "awwr" calls are used in pro­tect­ing or claim­ing ter­ri­tory from other fish crows. In­traspe­cific com­mu­ni­ca­tion calls such as a drawn-out "awwr" calls are used as a mob­bing call in re­la­tion to po­ten­tial preda­tors. Ag­gres­sive rat­tles are also used to show ag­gres­sion.

Fish crows tend to be more vocal dur­ing breed­ing sea­son. Beg­ging calls are used by nestlings, fledg­lings, and breed­ing fe­males, and is de­scribed as a higher pitched "awwr" call. Par­ents use feed­ing calls to wake up their young to give them food.

As for tac­tile com­mu­ni­ca­tions, most in­stances occur dur­ing shows of ag­gres­sion (such as mob­bing), breed­ing, or in­ter­ac­tion with young. Fish crows have been ob­served at­tack­ing other fish crows by peck­ing, grab­bing, or pulling their tails. There are no known courtship dis­plays. Be­fore breed­ing, male fish crows ei­ther touch or feed their fe­male mates. Dur­ing breed­ing, males step on the backs of fe­males. After breed­ing, pairs sit close to­gether. While brood­ing, males feed the fe­males. Fecal sacs are pre­sented by the young each time they defe­cate and are ei­ther eaten or re­moved by the par­ents.

While no sources on fish crows specif­i­cally state that they can see in color, it is as­sumed that they can see in color. Some vi­sual dis­plays of ag­gres­sion can occur (a threat pos­ture where crows will arch their necks, spread their wings, and walk side­ways to their op­po­nent), as well as ap­pease­ment dis­plays (beg­ging calls with half ex­tended wings and a low­ered body). They use vi­sual cues to track down bird and tur­tle nests in ad­di­tion to using vi­sual cues to for­age.

There are no spe­cific sources on the use of pheromones in fish crows but other birds do use pheromones to com­mu­ni­cate. Fish crows are as­sumed to have a sense of smell, as other closely re­lated crow species have a sense of smell. (Hardy, 1990; Laiolo and Rolando, 2003; Mc­Gowan, 2001; Zerega, 1880)

• Communication Channels
• visual
• tactile
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Fish crows are om­ni­vores with highly var­ied food habits. These birds are gen­er­ally ob­served steal­ing eggs from bird nests, and stud­ies have ob­served these crows steal­ing shore­bird eggs and tur­tle eggs (like Florida soft­shell tur­tles [Apalone ferox]). Some bird species preyed upon in­clude white ibises (Eu­docimus albus), Vir­ginia rails (Ral­lus lim­i­cola), and com­mon terns (Sterna hirundo). San­tis­te­ban et al. (2002) re­ported that vis­i­bil­ity is a key fac­tor in whether the crows prey upon a nest or not. They will also prey upon chicks, but will not ac­tively hunt them down.

Fish crows also con­sume fish, crabs, and in­ver­te­brates usu­ally found along the shore­line. Goren­zel et. al. (1994) ob­served fish crows prey­ing upon fish grown in aqua­cul­ture fa­cil­i­ties.

In agri­cul­tural areas, fish crows con­sume waste grain and ticks found on cat­tle. They will search for grubs in plowed fields. They will also hunt fly­ing in­sects and spi­ders.

Mc­Gowan (2001) ob­served fish crows drink­ing nec­tar from a tiger's claw tree (Eryn­thia). They also con­sume fruit like mul­ber­ries (Morus) and seeds.

In urban areas, fish crows eat garbage and there­fore search for food in dump­sters and at garbage dumps. Fish crows also con­sume car­rion, and have been ob­served in­gest­ing dead fish and birds. (Goren­zel, et al., 1994; Hamel, 1992; Mc­Gowan, 2001; Mon­tevec­chi, 1978; San­tis­te­ban, et al., 2002; Shields and Par­nell, 1986)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • piscivore
  • eats eggs
  • insectivore
  • eats non-insect arthropods
  • scavenger
• herbivore
  • frugivore
  • granivore
  • nectarivore
• omnivore

• Animal Foods
• birds
• fish
• eggs
• carrion
• insects
• terrestrial non-insect arthropods
• other marine invertebrates

• Plant Foods
• seeds, grains, and nuts
• fruit
• nectar

Pre­da­tion

Pre­da­tion on fish crows com­monly oc­curs dur­ing nest­ing sea­son. Rac­coons (Pro­cyon lotor), rat snakes (Pan­therophis), and east­ern gray squir­rels (Sci­u­rus car­o­li­nen­sis) prey upon fish crow eggs. Owls, red-tailed hawks (Buteo ja­maicen­sis), Cooper's hawks (Ac­cip­iter cooperii), broad-winged hawks (Buteo platypterus), and Amer­i­can kestrels (Falco sparverius) prey upon fish crow young and adults. Mc­Gowan (2001) states that hu­mans (Homo sapi­ens) are a com­mon nest preda­tor.

Both male and fe­male fish crows at­tempt to scare off preda­tors through mob­bing be­hav­iors, such as swoop­ing down at preda­tors. They will also make warn­ing calls. When an alarm call is sounded, fish crows flock to­gether to mob preda­tors. (Mc­Gowan, 2001)

• Known Predators

  • American kestrel (Falco sparverius)
  • broad-winged hawk (Buteo platypterus)
  • Cooper's hawk (Accipiter cooperii)
  • eastern gray squirrel (Sciurus carolinensis)
  • raccoon (Procyon lotor)
  • rat snakes (Pantherophis)
  • red-tailed hawk (Buteo jamaicensis)
  • humans (Homo sapiens)

Ecosys­tem Roles

Fish crows are nest preda­tors and seed dis­trib­u­tors (seeds have been found in their feces). Fish crows are eaten by preda­tory birds like Amer­i­can kestrels (Falco sparverius). Their young and eggs are preyed upon by squir­rels and rac­coons (Pro­cyon lotor).

Fish crows are hosts to ec­topar­a­sites such as chew­ing lice (Myr­sidea amer­i­cana) and crow lice (Philopterus corvi). Dusek and For­rester (2002) ob­served sev­eral blood par­a­sites af­fect­ing fish crows in­clud­ing pro­to­zoans that cause Avian Malaria (Haemo­pro­teus danilewskii and Haemo­pro­teus picae). They also ob­served the bac­terium Plas­mod­ium re­lic­tum, which causes My­cobac­terium Avian Com­plex in­fec­tions. Fish crows are also sus­cep­ti­ble to West Nile Virus in­fec­tions. (Dusek and For­rester, 2002; Mc­Gowan, 2001)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Hu­mans ben­e­fit from fish crows in re­search and ed­u­ca­tion fields, as they can be used to re­search how nest preda­tors can find nests on which to prey (San­tis­te­ban et al., 2002). Fish crows are also used in West Nile virus re­search.

His­tor­i­cally, fish crows were pop­u­lar with bird watch­ers. In Arkansas, peo­ple can hunt fish crows from Sep­tem­ber 1 through Feb­ru­ary 21 (on Mon­days through Thurs­days only) and there is no bag or pos­ses­sion lim­its for fish crows. They are hunted for sport, not food. (Hardy, 1990; Mc­Gowan, 2001; Reese, 2015; San­tis­te­ban, et al., 2002)

• Positive Impacts
• ecotourism
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Goren­zel et al. (1994) re­port that fish crows are fre­quent pests at aqua­cul­ture fa­cil­i­ties and have also been ob­served eat­ing crops in rural areas. Fish crows can also trans­fer West Nile Virus to hu­mans. (Goren­zel, et al., 1994; Mc­Gowan, 2001; Turell, et al., 2003)

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Con­ser­va­tion Sta­tus

Fish crows are listed as a species of "Least Con­cern" on the IUCN Red list, and their pop­u­la­tions are grow­ing. They are listed as pro­tected from being hunted in most states by the United States Mi­gra­tory Bird Treaty Act. They are not men­tioned in the United States Fed­eral list, CITES, or the State of Michi­gan list.

Threats to fish crows in­clude hunt­ing in some states (like Arkansas) where they are con­sid­ered to be pests. Hunt­ing is con­sid­ered to be the num­ber one cause of death in fish crows. In the early 2000s, there was an out­break of West Nile Virus in fish crows, but their num­bers have since re­cov­ered and in­creased since the out­break.

While fish crows can be hunted, there are rules in place to pro­tect pop­u­la­tions as a whole. States are not to allow hunt­ing dur­ing nest­ing sea­son, hunt­ing sea­sons are not to be longer than 124 days, and crows are only al­lowed to be killed using firearms, fal­conry, or through archery. States are al­lowed to set their own hunt­ing sea­sons, bag lim­its, and pos­ses­sion lim­its. Due to the range ex­pan­sion of fish crows, their pop­u­la­tions are ex­pected to con­tinue grow­ing. (Arkansas Game and Fish­ing Com­mis­sion, 2019; Birdlife In­ter­na­tional, 2016; Mc­Gowan, 2001)

• IUCN Red List

  Least Concern

• US Migratory Bird Act

  Protected

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Re­becca Salen (au­thor), Rad­ford Uni­ver­sity, Lau­ren Bur­roughs (ed­i­tor), Rad­ford Uni­ver­sity, Logan Platt (ed­i­tor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Galen Bur­rell (ed­i­tor), Spe­cial Pro­jects.

Ref­er­ences

Arkansas Game and Fish­ing Com­mis­sion, 2019. "Arkansas Game and Fish­ing Com­mis­sion" (On-line). Ac­cessed April 07, 2020 at https://​www.​agfc.​com/​en/​hunting/​migratory-birds/​crow/​.

Birdlife In­ter­na­tional, 2016. "Corvus os­sifra­gus." (On-line). The IUCN Red List of Threat­ened Species 2016: e.T22705993A94045235. Ac­cessed April 07, 2020 at https://​dx.​doi.​org/​10.​2305/​IUCN.​UK.​2016-3.​RLTS.​T22705993A94045235.​en.​.

Clapp, 1983. Longevity records of North Amer­i­can birds: Columbidae through Pari­dae. Jour­nal of Field Or­nithol­ogy, 54: 123-137.

Dusek, R., D. For­rester. 2002. Blood par­a­sites of Amer­i­can crows (Corvus brachyrhyn­chos) and fish crows (Corvus os­sifra­gus) in Florida, U.S.A.. Com­par­a­tive Par­a­sitol­ogy, 69/1: 92-96.

Goren­zel, W., F. Conte, T. Salmon. 1994. Bird dam­age at aqua­cul­ture fa­cil­i­ties. The Hand­book: Pre­ven­tion and Con­trol of Wildlife Dam­age, N/A: 57. Ac­cessed Feb­ru­ary 17, 2020 at https://​digitalcommons.​unl.​edu/​icwdmhandbook/​57/​.

Hamel, P. 1992. The Land Man­ager's Guide to the Birds of the South. Asheville, North Car­olina: U.S. De­part­ment of Agri­cul­ture, For­est Ser­vice, South­east­ern For­est Ex­per­i­ment Sta­tion.

Hardy, J. 1990. The fish crow (Corvus os­sifra­gus) and its Mex­i­can rel­a­tives: Vocal clues to evo­lu­tion­ary re­la­tion­ships?. Florida Field Nat­u­ral­ist, 18/4: 74-80.

Har­ing, E., B. Dāubl, W. Pinsker, A. Kryukov, A. Gamauf. 2012. Ge­netic di­ver­gences and in­traspe­cific vari­a­tion in corvids of the genus Corvus (Aves: Passerir­formes: Corvi­dae) - A first sur­vey based on mu­seum spec­i­mens. Jour­nal of Zo­o­log­i­cal Sys­tem­at­ics and Evo­lu­tion­ary Re­search, 50/3: 230-246.

Har­ri­son, C. 1978. A Field Guide to the Nests, Eggs, and Nestlings of North Amer­i­can Birds. Cleve­land, Ohio: Collins Press.

Head­strom, R. 1970. A Com­plete Field Guide to Nests in the United States (In­clud­ing those of Birds, Mam­mals, In­sects, Fishes, Rep­tiles, and Am­phib­ians). New York, New York: Van Rees Press.

Jones, J. 1990. Where the Birds Are. New York, New York: William Mor­row and Com­pany, Inc.

Jor­gensen, J., M. Panella, W. Sil­cock, K. Stoner. 2009. The fish crow (Corvus os­sifra­gus) reaches Ne­braska. Ne­braska Bird Re­view, 77/4: 155-159.

Laiolo, P., A. Rolando. 2003. The evo­lu­tion of vo­cal­i­sa­tions in the genus Corvus: Ef­fects of phy­logeny, mor­phol­ogy, and habi­tat. Evo­lu­tion­ary Ecol­ogy, 17: 111-123.

Mc­Gowan, K. 2001. Fish crow (Corvus os­sifra­gus) ver­sion 2.0. Pp. none in A Poole, F Gill, eds. Birds of North Amer­ica. Ithaca, NY: Cor­nell Lab of Or­nithol­ogy. Ac­cessed Feb­ru­ary 04, 2020 at https://​doi.​org/​10.​2173/​bna.​589.

Mon­tevec­chi, W. 1978. Corvids using ob­jects to dis­place gulls from nests. The Con­dor, 80/3: 349.

Pe­ters, H. 1938. A list of ex­ter­nal par­a­sites from birds of the east­ern part of the United States. Bird-Band­ing, 7/1: 9-27.

Poole, E. 1938. Weights and wing areas in North Amer­i­can birds. The Auk, 55/3: 511-517.

Reese, J. 2015. Fish crows (Corvus os­sifra­gus) uti­lize un­usual nest­ing lo­ca­tion and habi­tat. Mary­land Birdlife, 64/1: 42-50.

Reese, J., P. Mc­Gowan, L. Staver, C. Calla­han. 2015. Fish crows (Corvus os­sifra­gus) prey on eggs of Vir­ginia rail (Ral­lus lim­i­cola) and com­mon tern (Sterna hirundo). Mary­land Birdlife, 64/1: 51-57.

San­tis­te­ban, L., K. Siev­ing, M. Avery. 2002. Use of sen­sory cues by fish crows Corvus os­sifra­gus prey­ing on ar­ti­fi­cial bird nests. Jour­nal of Avian Bi­ol­ogy, 33/3: 245-252.

Shields, M., J. Par­nell. 1986. Fish crow pre­da­tion on eggs of the white ibis at Bat­tery Is­land, North Car­olina. The Auk, 103/3: 531-539.

Turell, M., M. Bun­ning, G. Lud­wig, B. Ort­man, J. Chang, T. Speaker, A. Spiel­man, R. McLean, N. Komar, R. Gates, T. Mc­Na­mara, T. Creek­more, L. Far­ley, C. Mitchell. 2003. DNA vac­cine for West Nile Virus in­fec­tion in fish crows (Corvus os­sifra­gus). Emerg­ing In­fec­tious Dis­eases, 9: 1077–1081. Ac­cessed April 07, 2020 at https://​www.​ncbi.​nlm.​nih.​gov/​pmc/​articles/​PMC3016768/​.

Wells, J., K. Mc­Gowan. 1991. Range ex­pan­sion in fish crow (Corvus os­sifra­gus): The Ithaca, NY, colony as an ex­am­ple. The King­bird, 41/2: 73-81.

Zerega, L. 1880. Notes on the north­ern range of the fish crow (Corvus os­sifra­gus), with some ac­count of its habits. Bul­letin of the Nut­tall Or­nitho­log­i­cal Club, 5/4: 205-208.