Hawaiian crow

Before the Hawaiian crow became extinct in the wild, the species was found only in the western and southeastern parts of Hawaii. It inhabited dry and mesic forests on the slopes of Mauna Loa and Hualālai at elevations of 3,000 to 6,000 feet.{{Cite web|title = 'Alalā – Pacific Islands Fish and Wildlife Office|url = http://www.fws.gov/pacificislands/fauna/alala.html|website = www.fws.gov|access-date = October 30, 2015}} Ōhi{{okina}}a lehua (Metrosideros polymorpha) and koa (Acacia koa) were important tree species in its wild habitat. Extensive understory cover was necessary to protect the ʻalalā from predation by the Hawaiian hawk, or {{okina}}io (Buteo solitarius). Nesting sites of the ʻalalā received {{convert|600|-|2500|mm|in}} of annual rainfall.{{cite report |date=October 2003 |title=Draft Revised Recovery Plan for the ʻAlalā (Corvus hawaiiensis) |publisher=United States Fish and Wildlife Service |url=http://www.fws.gov/pacific/ecoservices/endangered/recovery/documents/AlalaDraftRevisedRecoveryPlan.pdf }} Fossil remains indicate that the Hawaiian crow used to be relatively abundant on all the main islands of Hawaii, along with four other now-extinct crow species.

The Hawaiian crow was also preyed on by rats and the small Asian mongooses (Urva auropunctata). Feral cats that introduced Toxoplasma gondii to the birds can also prey on chicks that are unable to fly. As of 2012, the Hawaiian crow's current population is 114 birds, the vast majority of which are in Hawaiian reserves.{{Cite web|title = Alala – The Hawaiian Crow {{!}} BirdNote|url = http://birdnote.org/show/alala-hawaiian-crow|website = birdnote.org|access-date = October 30, 2015}}

The omnivorous Hawaiian crow is a generalist species, eating various foods as they become available. The main portion of their diet and 50% of their feeding activity is spent foraging on trunks, branches, and foliage for invertebrates such as isopods, land snails, and arachnids. They feed in a woodpecker fashion, flaking bark and moss from trunks or branches to expose hidden insects, foraging mostly on ohia and koa, the tallest and most dominant trees in their habitats. Fruits are the second most dominant component in the Hawaiian crow's diet. The crows often collect kepau and olapa fruit clusters. Although hoawa and alani fruits have hard outer coverings, crows continue to exert energy prying them open. Passerine Nestlings and eggs are consumed most frequently in April and May, during their breeding season. Other prey include red-billed leiothrix, Japanese white-eye, Hawaiʻi ʻamakihi, ʻIʻiwi, ʻelepaio, and ʻapapane. The {{okina}}alalā also commonly forages on flowers, especially from February through May. Nectar to feed the young is obtained from the ohia flower, oha kepau, and purple poka during the nestling period. Crows also foraged various plant parts, including the flower petals of kolea, koa, and mamane. The palila is the only other Hawaiian bird known to eat flower petals. The {{okina}}alalā only occasionally forages on the ground, but only for a limited amount of time for risk of predators.{{Cite journal|title = Foraging Ecology of the Hawaiian Crow, an Endangered Generalist|jstor = 1368918|journal = The Condor|date = May 1, 1986|pages = 211–219|volume = 88|issue = 2|doi = 10.2307/1368918|first1 = Howard F.|last1 = Sakai|first2 = C. John|last2 = Ralph|first3 = C. D.|last3 = Jenkins}}

{{main|Tool use by animals#Corvids}}

Captive individuals can use sticks as tools to extract food from holes drilled in logs. The juveniles exhibit tool use without training or social learning from adults, and it is believed to be a species-wide ability.{{cite web|url=http://www.care2.com/causes/scientists-discover-tool-use-in-brilliant-hawaiian-crow.html|title=Scientists discover tool use in brilliant Hawaiian crow|author=Graef, A.|date=September 16, 2016|access-date=September 18, 2016|publisher=Care2|archive-url=https://web.archive.org/web/20190711135436/https://www.care2.com/causes/scientists-discover-tool-use-in-brilliant-hawaiian-crow.html|archive-date=July 11, 2019|url-status=dead}}{{cite journal|title=Discovery of species-wide tool use in the Hawaiian crow|journal=Nature|volume=537|issue=7620|pages=403–407|year=2016|doi=10.1038/nature19103|author=Rutz, C.|display-authors=etal|pmid=27629645|bibcode=2016Natur.537..403R|hdl=10023/10465|s2cid=205250218|url=http://opus.bath.ac.uk/52301/1/Rutz_etal_2016_Nature.pdf}}{{cite press release |author= |title= Tropical crow species is highly skilled tool user|url= http://phys.org/news/2016-09-tropical-crow-species-highly-skilled.html#jCp|publisher= Phys.org|date= September 14, 2016|access-date=September 15, 2016}}

The Hawaiian crow has a call described variously as a two-toned caw and as a screech with lower tones added, similar to a cat's meow. In flight, this species has been known to produce a wide variety of calls including a repeated kerruk, kerruk sound and a loud kraa-a-a-ik sound. It also makes a ca-wk sound, has a complex, burbling song, and makes a variety of other sounds as well.{{Cite web|title = Hawaiian Bird Conservation Action Plan – Hawaiian Crow|url = https://www.pacificrimconservation.org/publications/|website = Pacific Rim Conservation|access-date = October 29, 2015|date = 2013|type = pdf}} The {{okina}}alalā has at least 24 calls in its repertoire, including alarm calls, contact calls, and calls signifying submission or courtship.{{Cite journal |last1=Tanimoto |first1=Ann M. |last2=Hart |first2=Patrick J. |last3=Pack |first3=Adam A. |last4=Switzer |first4=Richard |date=March 1, 2017 |title=Vocal repertoire and signal characteristics of 'Alalā, the Hawaiian Crow (Corvus hawaiiensis) |url=https://bioone.org/journals/the-wilson-journal-of-ornithology/volume-129/issue-1/1559-4491-129.1.25/Vocal-repertoire-and-signal-characteristics-of-Alal%c4%81-the-Hawaiian-Crow/10.1676/1559-4491-129.1.25.full |journal=The Wilson Journal of Ornithology |volume=129 |issue=1 |pages=25–35 |doi=10.1676/1559-4491-129.1.25 |s2cid=90268444 |issn=1559-4491|url-access=subscription }}

File: Corvus hawaiiensis medley.oggThis is a medley of the different calls the Hawaiian Crow makes.{{Cite web|title = U.S. Fish & Wildlife Service Endangered Species|url = http://www.fws.gov/pacific/ecoservices/endangered/recovery/Alala_Voices.html|website = www.fws.gov|access-date = October 30, 2015}}

Female crows are considered sexually mature at about 2 or 3 years of age and males at 4 years."NatureServe Explorer: Species Name Criteria – All Species – Scientific or Informal Taxonomy,

Species – Informal Names." NatureServe Explorer: Species Name Criteria – All Species – Scientific or Informal Taxonomy, Species – Informal Names. NatureServe. Web. October 29, 2015.

The Hawaiian crow's breeding season lasts from March to July; it builds a nest in March or April, lays eggs in mid-to-late April, and the eggs hatch in mid-May. Both sexes construct nests with branches from the native ohi'a tree strengthened with grasses. The crow typically lays one to five eggs (that are greenish-blue in color) per season, although at most only two will survive past the fledgling phase.{{Cite web|title = Comprehensive Report Species -|url = http://explorer.natureserve.org/servlet/NatureServe?sourceTemplate=tabular_report.wmt&loadTemplate=species_RptComprehensive.wmt&selectedReport=RptComprehensive.wmt&summaryView=tabular_report.wmt&elKey=104216&paging=home&save=true&startIndex=1&nextStartIndex=1&reset=false&offPageSelectedElKey=104216&offPageSelectedElType=species&offPageYesNo=true&post_processes=&radiobutton=radiobutton&selectedIndexes=104216:|website = explorer.natureserve.org|access-date = October 30, 2015|archive-date = August 13, 2016|archive-url = https://web.archive.org/web/20160813005902/http://explorer.natureserve.org/servlet/NatureServe?sourceTemplate=tabular_report.wmt&loadTemplate=species_RptComprehensive.wmt&selectedReport=RptComprehensive.wmt&summaryView=tabular_report.wmt&elKey=104216&paging=home&save=true&startIndex=1&nextStartIndex=1&reset=false&offPageSelectedElKey=104216&offPageSelectedElType=species&offPageYesNo=true&post_processes=&radiobutton=radiobutton&selectedIndexes=104216:|url-status = dead}} Only the females incubate the 2–5 eggs for 19–22 days and brood the young, of which only 1–2 fledge about 40 days after hatching. If the first clutch is lost, the pair will re-lay, which serves to be helpful in captive breeding efforts. Juveniles rely on their parents for 8 months and will stay with the family group until the next breeding season.

The {{okina}}alalā was one of the largest native bird populations in Hawaii. Its disappearance in the wild has had cascading effects on the environment, especially with the seed dispersal of the native plants. Many of these plants rely on the {{okina}}alalā not only for seed dispersal but also for seed germination as seeds are passed through the crow's digestive system. Without seed dispersal, the plants have no means of growing another generation. The {{okina}}alalā plays a key role in the maintenance of many indigenous plant species, which now could become a rarity in Hawaii's ecosystems, specifically the dry forests, without their main seed disperser.{{Cite journal|title = Seed dispersal by a captive corvid: the role of the 'Alalā (Corvus hawaiiensis) in shaping Hawai'i's plant communities|jstor = 41722888|journal = Ecological Applications|date = September 1, 2012|pages = 1718–1732|volume = 22|issue = 6|first1 = Susan|last1 = Culliney|first2 = Liba|last2 = Pejchar|first3 = Richard|last3 = Switzer|first4 = Viviana|last4 = Ruiz-Gutierrez|doi=10.1890/11-1613.1|pmid = 23092010| s2cid=23240239 |doi-access = free| bibcode=2012EcoAp..22.1718C }} The Hawaiian crow has become known as an indicator species; the disappearance of the {{okina}}alalā indicates serious environmental problems.{{Cite journal|title = Random Samples|jstor = 2877246|journal = Science|date = May 22, 1992|pages = 1136–1137|volume = 256|series = New Series|issue = 5060|first = Constance|last = Holden|bibcode = 1992Sci...256.1136H|doi = 10.1126/science.256.5060.1136|s2cid = 241636345}}

File:Corvus hawaiiensis in grass.jpg

The Hawaiian crow faces an ample number of threats in the wild, which are considered contributing factors to their extinction in the wild. Small population size makes the species more vulnerable to environmental fluctuations; this leads to a higher likelihood of inbreeding, which reduces the likelihood that offspring will survive to recruitment.{{Cite journal |last1=Flanagan |first1=Alison M. |last2=Masuda |first2=Bryce |last3=Grueber |first3=Catherine E. |last4=Sutton |first4=Jolene T. |date=August 2021 |title=Moving from trends to benchmarks by using regression tree analysis to find inbreeding thresholds in a critically endangered bird |url=https://conbio.onlinelibrary.wiley.com/doi/10.1111/cobi.13650 |journal=Conservation Biology |language=en |volume=35 |issue=4 |pages=1278–1287 |doi=10.1111/cobi.13650 |pmid=33025666 |bibcode=2021ConBi..35.1278F |s2cid=222182269 |issn=0888-8892|url-access=subscription }}

{{okina}}Alalā select habitat with ample cover and prefer areas with a large proportion of native plants for food and shelter.{{Cite journal |last1=Giffin |first1=Jon G. |last2=Scott |first2=J. Michael |last3=Mountainspring |first3=Stephen |date=1987 |title=Habitat Selection and Management of the Hawaiian Crow |url=https://www.jstor.org/stable/3801038 |journal=The Journal of Wildlife Management |volume=51 |issue=2 |pages=485–494 |doi=10.2307/3801038 |jstor=3801038 |issn=0022-541X|url-access=subscription }} Polynesian and European farmers removed dry, lowland forest, restricting the {{okina}}alalā to forest at higher elevation. After settlement by Europeans, the higher elevation forest was also compromised by extensive logging and ranching, and farm animals such as cattle, pigs, sheep, and goats being allowed to graze freely in these areas.

Polynesian cultures valued {{okina}}alalā feathers for use in kāhili and for decorating idols used during the Makahiki season. For this purpose, professional birdcatchers (known as kia manu) working for King Kamehameha or local priests (ali'i) were known to snare and hunt {{okina}}alalā with poles.{{Cite journal |last=Pérez |first=Francisco L. |date=December 2021 |title=The Silent Forest: Impact of Bird Hunting by Prehistoric Polynesians on the Decline and Disappearance of Native Avifauna in Hawai'i |journal=Geographies |language=en |volume=1 |issue=3 |pages=192–216 |doi=10.3390/geographies1030012 |doi-access=free |issn=2673-7086}}

{{okina}}Alalā were also shot for sport by European colonizers. Though hunting native birds was illegal at the time, {{okina}}alalā continued to be shot throughout the 1980s, according to conservationists.{{Cite journal |last1=Van Riper |first1=Charles |last2=Scott |first2=J. Michael |date=2001 |title=Limiting factors affecting Hawaiian native birds |url=https://sora.unm.edu/node/87 |journal=Studies in Avian Biology |issue=22 |pages=221–223}}

The {{okina}}alalā's known extant natural predator is the 'io (Hawaiian hawk), a hawk species endemic to Hawaii.

Several mammal species introduced to Hawaii by humans are known to prey on {{okina}}alalā eggs, nestlings, and fledglings. These include the roof rat (Rattus rattus), the small Indian mongoose, and feral cats, which have been known to attack nests, eat eggs, and kill young fledglings.

Avian malaria is a parasitic disease of birds, caused by Plasmodium relictum, a protozoan parasite passed to birds via mosquitoes of the species Culex quinquefasciatus, which was introduced to the Hawaiian islands in 1826.{{Cite journal |last1=LaPointe |first1=Dennis A. |last2=Atkinson |first2=Carter T. |last3=Samuel |first3=Michael D. |date=February 2012 |title=Ecology and conservation biology of avian malaria |url=https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.2011.06431.x |journal=Annals of the New York Academy of Sciences |language=en |volume=1249 |issue=1 |pages=211–226 |doi=10.1111/j.1749-6632.2011.06431.x |pmid=22320256 |bibcode=2012NYASA1249..211L |issn=0077-8923}} Though this disease appears in many passerine birds without much population impact, many isolated bird populations show significant mortality when introduced to this parasite, including native Hawaiian birds. Many Hawaiian bird species have shown precipitous population declines which are thought to be due to avian malaria. Though there is no direct evidence implicating avian malaria in the decline of the {{okina}}alalā, they are vulnerable to the disease. Seven captive {{okina}}alalā, housed in outdoor aviaries, were naturally infected with avian malaria over the course of a seven-week study, and two of those infected showed clinical signs of the illness.{{Cite journal |last1=Massey |first1=J. Gregory |last2=Graczyk |first2=Thaddeus K. |last3=Cranfield |first3=Michael R. |date=1996 |title=Characteristics of Naturally Acquired Plasmodium relictum capistranoae Infections in Naive Hawaiian Crows (Corvus hawaiiensis) in Hawaii |url=https://www.jstor.org/stable/3284139 |journal=The Journal of Parasitology |volume=82 |issue=1 |pages=182–185 |doi=10.2307/3284139 |jstor=3284139 |pmid=8627494 |issn=0022-3395|url-access=subscription }}

Avian pox is an infection caused by viruses in the genus Avipoxvirus. Infection causes tumor-like lesions on the exposed skin of the legs and feet and in and around the beak, trachea, and esophagus. Avian pox is also spread by mosquitos, and through contact with infected birds or objects.{{Cite journal |last1=Atkinson |first1=Carter T. |last2=LaPointe |first2=Dennis A. |date=2009 |title=Introduced Avian Diseases, Climate Change, and the Future of Hawaiian Honeycreepers |url=https://www.jstor.org/stable/27670709 |journal=Journal of Avian Medicine and Surgery |volume=23 |issue=1 |pages=53–63 |doi=10.1647/2008-059.1 |jstor=27670709 |pmid=19530408 |bibcode=2009JAvMS..23...53A |s2cid=46048652 |issn=1082-6742|url-access=subscription }} In experimental studies on other native Hawaiian birds, avian pox has been shown to cause large lesions, which often become infected, leading to tissue necrosis.{{Cite journal |last=Warner |first=Richard E. |date=April 1968 |title=The Role of Introduced Diseases in the Extinction of the Endemic Hawaiian Avifauna |url=https://doi.org/10.2307/1365954 |journal=The Condor |volume=70 |issue=2 |pages=101–120 |doi=10.2307/1365954 |jstor=1365954 |issn=0010-5422|url-access=subscription }} Infections can sometimes lead to death.{{Cite journal |last1=van Riper |first1=Charles |last2=van Riper |first2=Sandra G. |last3=Hansen |first3=Wallace R. |date=October 1, 2002 |title=Epizootiology and Effect of Avian Pox on Hawaiian Forest Birds |url=https://doi.org/10.1093/auk/119.4.929 |journal=The Auk |volume=119 |issue=4 |pages=929–942 |doi=10.1093/auk/119.4.929 |issn=1938-4254|url-access=subscription }} {{okina}}Alalā have been known to become infected with avian pox, including during reintroduction efforts,{{Cite journal |last1=Tripathy |first1=Deoki N. |last2=Schnitzlein |first2=William M. |last3=Morris |first3=Patrick J. |last4=Janssen |first4=Don L. |last5=Zuba |first5=Jeffery K. |last6=Massey |first6=Greg |last7=Atkinson |first7=Carter T. |date=April 2000 |title=Characterization of Poxviruses from Forest Birds in Hawaii |url=https://doi.org/10.7589/0090-3558-36.2.225 |journal=Journal of Wildlife Diseases |volume=36 |issue=2 |pages=225–230 |doi=10.7589/0090-3558-36.2.225 |pmid=10813603 |bibcode=2000JWDis..36..225T |issn=0090-3558}}{{Cite web |last1=Hawai'i Department of Land and Natural Resources Division of Forestry and Wildlife |last2=Hawai'i Department of Land and Natural Resources Division of Forestry and Wildlife |date=October 16, 2023 |title=Environmental Assessment for Pilot Release of ʻAlalā (Corvus hawaiiensis) on East Maui, Hawai'i |url=https://dlnr.hawaii.gov/dofaw/files/2023/10/Final-DRAFT-EA-for-Alala-Release-on-East-Maui.pdf |archive-url=https://web.archive.org/web/20231028182053/https://dlnr.hawaii.gov/dofaw/files/2023/10/Final-DRAFT-EA-for-Alala-Release-on-East-Maui.pdf |archive-date=October 28, 2023 |access-date=March 5, 2024}} but the role, if any, of the disease in their decline is unknown.

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii. It is spread by domestic cats, who can transmit eggs and parasites to practically every known warm-blooded vertebrate, including birds, in their feces.{{Cite book |last=Dubey |first=JP |url=https://onlinelibrary.wiley.com/doi/book/10.1002/9780813804620 |title=Parasitic Diseases of Wild Birds |date=December 19, 2008 |publisher=Wiley |isbn=978-0-8138-2081-1 |editor-last=Atkinson |editor-first=Carter T. |edition=1 |pages=204–222 |language=en |chapter=Toxoplasma |doi=10.1002/9780813804620 |editor-last2=Thomas |editor-first2=Nancy J. |editor-last3=Hunter |editor-first3=D. Bruce}} Though toxoplasmosis rarely causes disease and death in infected animals, infection was diagnosed in five reintroduced {{okina}}alalā in 1998–1999. One presented with clinical signs and was successfully treated, three appeared to have died from the disease, and one was diagnosed but did not appear to show clinical signs of the disease.{{Cite journal |last1=Work |first1=Thierry M. |last2=Massey |first2=J. Gregory |last3=Rideout |first3=Bruce A. |last4=Gardiner |first4=Chris H. |last5=Ledig |first5=David B. |last6=Kwok |first6=O.C.H. |last7=Dubey |first7=J.P. |title=Fatal Toxoplasmosis in Free-Ranging Endangered 'Alala from Hawaii |url=https://meridian.allenpress.com/jwd/article/36/2/205/122615/FATAL-TOXOPLASMOSIS-IN-FREE-RANGING-ENDANGERED |journal=Journal of Wildlife Diseases |date=2000 |volume=36 |issue=2 |pages=205–212|doi=10.7589/0090-3558-36.2.205 |pmid=10813600 |bibcode=2000JWDis..36..205W }} During reintroduction efforts between 2016–2020, several birds showed evidence in blood samples that they had had prior toxoplasmosis infections, though no birds tested positive for active infections. Cats are not native to the Hawaiian islands, and {{okina}}alalā are therefore naive hosts to the parasite; this is often associated with higher virulence and susceptibility.{{Cite journal |last1=Hollings |first1=Tracey |last2=Jones |first2=Menna |last3=Mooney |first3=Nick |last4=McCallum |first4=Hamish |date=December 1, 2013 |title=Wildlife disease ecology in changing landscapes: Mesopredator release and toxoplasmosis |journal=International Journal for Parasitology: Parasites and Wildlife |volume=2 |pages=110–118 |doi=10.1016/j.ijppaw.2013.02.002 |issn=2213-2244 |pmc=3862529 |pmid=24533323|bibcode=2013IJPPW...2..110H }} Whether or not toxoplasmosis has contributed to historic declines of {{okina}}alalā is unknown; however, it has been a consideration in conservation efforts for the species.{{Cite news |last1=Ball |first1=Donna |last2=Joaquin |first2=Iwikau'ikaua |last3=Ka'aha'aina |first3=Lea |last4=Laut |first4=Megan |last5=Nelson |first5=Jay |date=March 22, 2016 |title=Restoring 'alala to the Hawaiian forest |url=https://www.thefreelibrary.com/Restoring+%27alala+to+the+Hawaiian+forest-a0459723642 |url-status=live |archive-url=https://web.archive.org/web/20240301211510/https://www.thefreelibrary.com/Restoring+%27alala+to+the+Hawaiian+forest-a0459723642 |archive-date=March 1, 2024 |access-date=March 1, 2024 |work=Endangered Species Bulletin}}

File:Corvus hawaiiensis.JPG

The Hawaiian crow is the most endangered corvid species in the world and the only corvid species left in Hawaii. Like other critically endangered species, harming the Hawaiian crow is illegal under U.S. federal law.{{Cite web |last=Fisheries |first=NOAA |date=2023-06-13 |title=Endangered Species Act {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/national/endangered-species-conservation/endangered-species-act |access-date=2024-03-04 |website=NOAA |language=en}} By 1994, the overall population had dwindled to 31 individuals; 8 to 12 were wild and 19 held in captivity. The only wild-born juvenile produced between 1992–2003 was last seen in 1997. The last two known wild individuals of the Hawaiian crow disappeared in 2002,{{cite journal |last=Walters |first=Mark Jerome |date=October–December 2006 |title=Do No Harm |journal=Conservation Magazine |publisher=Society for Conservation Biology |volume=7 |issue=4 |pages=28–34 |url=http://www.conbio.org/cip/article74har.cfm |access-date=January 8, 2007 |archive-url=https://web.archive.org/web/20070927035408/http://www.conbio.org/cip/article74har.cfm |archive-date=September 27, 2007 |url-status=dead }} and the species is now classified as Extinct in the Wild by the IUCN Red List. Some 115 individuals remain (as of August 2014){{cite news |author=KFMB-TV |date=August 9, 2014 |title=Hawaiian crow breeding season a success |url=http://www.cbs8.com/story/26240475/hawaiian-crow-breeding-season-a-success/ |access-date=August 13, 2014}} in two captive breeding facilities operated by the San Diego Zoo. Attempts to reintroduce captive-bred birds into the wild have been hampered by predation by the Hawaiian hawk (Buteo solitarius), which itself is listed as Near Threatened. Breeding efforts have also been complicated due to extensive inbreeding during the crow's population decline.{{Cite web|title = Hawaiian Crow (Corvus hawaiiensis) – BirdLife species factsheet|url = http://www.birdlife.org/datazone/speciesfactsheet.php?id=5793|website = www.birdlife.org|access-date = October 30, 2015}}

The {{okina}}alalā has been legally protected by the state of Hawaii since 1931 and was recognized as federally endangered in 1967. Sites on the slopes of Mauna Loa and other natural ranges have been set aside for habitat reconstruction and native bird recovery since the 1990s. The Kūlani Keauhou area has been ranked the best spot for the crows, parts of which have been fenced and ungulate-free for 20 years, helping tremendously for habitat recovery.

The first {{okina}}alalā to be brought into captivity were two fledglings infected with avian pox in the wild in 1970 so they could receive treatment. By 1981, 12 individuals had been brought into captivity due to concerns about the viability of the wild population; 10 were housed in an endangered species breeding facility on Hawaii island. In 1986, the remaining captive {{okina}}alalā were transferred to a breeding facility on Maui. In 1996, a new captive breeding facility was completed near Volcano on Hawaii- the captive population of {{okina}}alalā was thereafter split between these two sites. In 2000, management of both captive breeding centers was taken over by San Diego Zoo Wildlife Alliance.

Initially, a majority of efforts to breed {{okina}}alalā proved unsuccessful. Between 1979 and 1991, 33 unbroken, fertile eggs were produced in captivity, but only 8 chicks hatched. Difficulties with artificial incubation, issues with males disturbing nesting females, and problems associated with inbreeding, are all thought to have contributed to this low number.{{Cite journal |last1=Harvey |first1=Nancy C. |last2=Farabaugh |first2=Susan M. |last3=Druker |first3=Bill B. |date=January 1, 2002 |title=Effects of early rearing experience on adult behavior and nesting in captive Hawaiian crows (Corvus hawaiiensis) |journal=Zoo Biology |volume=21 |issue=1 |pages=59–75 |doi=10.1002/zoo.10024}} Because few chicks were produced each year and to prevent harm to the chicks from inept parents, birds were sometimes hand-reared without any siblings nearby. These individuals grew up to exhibit more stereotypies, a negative indicator for breeding success and fitness for release in the wild.

Over time, captive breeding has become more successful; the captive population increased from 24 in 1999 to more than 100 in 2012 with improved incubation, housing, and hand-rearing techniques.{{cite web |year=2013 |title=Focal Species: Hawaiian Crow or 'Alalā (Corvus hawaiiensis) |url=https://pacificrimconservation.org/wp-content/uploads/2013/10/Hawaiian%20Crow.pdf |access-date=August 20, 2023 |publisher=Pacific Rim Conservation: Hawaiian Bird Conservation Action Plan}} With more birds in the population, practitioners are now focused on increasing the population while simultaneously producing offspring more suited to release into the wild. This is achieved by socializing breeding pairs to encourage strong pair bonding, providing options of nest-building locations and materials, encouraging females to incubate eggs to hatch, and allowing parents to rear their own chicks to adulthood.{{Cite journal |last1=Flanagan |first1=Alison M. |last2=Masuda |first2=Bryce |last3=Komarczyk |first3=Lisa |last4=Kuhar |first4=Amy |last5=Farabaugh |first5=Susan |last6=Swaisgood |first6=Ronald R. |date=November 2023 |title=Adapting conservation breeding techniques using a data-driven approach to restore the 'Alalā (Hawaiian crow, Corvus hawaiiensis ) |journal=Zoo Biology |language=en |volume=42 |issue=6 |pages=834–839 |doi=10.1002/zoo.21794 |issn=0733-3188|doi-access=free |pmid=37341388 }} Experimentation with allowing adults to incubate and rear their own chicks began in 2011, and by 2023, 17% of the living population was the product of full parent-rearing.

There have been multiple attempted reintroductions of the {{okina}}alalā.

Between 1993 and 1998, 27 juvenile {{okina}}alalā, from eggs of both wild and captive origin, were raised in captivity and released on South Kona, Hawaii, near the remaining wild population. 21 of the 27 released birds died over the course of the program, many before reaching sexual maturity. The mortality rate of the reintroduced population was about twice that of the wild population at the time. The cause of death was determined for 13 of the 21 deceased birds- 7 were killed by Hawaiian hawks ('io), 3 died of toxoplasmosis infection, 2 died of other infections, and 1 was killed by nonnative mammal predation. In 1998 and 1999, the remaining 6 birds were recaptured and reintegrated into the captive flock.

In December 2016, 5 young {{okina}}alalā were released into the Pu'u Maka'ala Natural Area Reserve on the eastern side of the island of Hawai'i. By mid-January, 3 birds had been found dead and the remaining 2 were returned to captivity.{{Cite web |title='Alalā Released Dec. 14! |url=https://dlnr.hawaii.gov/alalaproject/2016/12/15/alala-released-dec-14/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}}{{Cite web |title=Press Release: RELEASED 'ALALĀ BROUGHT BACK INTO PROTECTIVE AVIARY AFTER LOSSES |url=https://dlnr.hawaii.gov/alalaproject/2017/01/18/press-release-released-alala-brought-back-into-protective-aviary-after-losses/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}} Necropsies found that 2 of the deaths were likely due to predation by the Hawaiian hawk and 1 was due to natural circumstances stemming from poor body condition.{{Cite web |title=ʻAlalā Reintroduction Project Planning Further Releases After Recent Challenges |url=https://dlnr.hawaii.gov/alalaproject/2017/03/09/%ca%bbalala-reintroduction-project-planning-further-releases-after-recent-challenges/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}}

A program of improved predator training was implemented in response to the previous deaths, and between 2017–2019, 27 young {{okina}}alalā were released in the Pu'u Maka'ala Natural Area Reserve in 3 separate release cohorts.{{Cite web |title=Press Release: ʻAlalā Project Looks to the Next Stage of Recovery |url=https://dlnr.hawaii.gov/alalaproject/2020/03/12/press-release-%ca%bbalala-project-looks-to-the-next-stage-of-recovery/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}} Though all birds released in 2017 and 2018 survived for over a year, birds released in 2019 survived for a shorter period- most died within 5 months of their release. Accelerating mortality into 2020 caused practitioners to recapture and return 5 surviving {{okina}}alalā to captivity. 7 deaths were likely caused by Hawaiian hawk predation, 3 from poor condition, 2 by intraspecific aggression, and 1 by nonnative mammal predation.

In contrast to the reintroduction efforts during the 1990s, some birds released in the 2010s showed breeding behavior in the wild, though it was ultimately unsuccessful. In May 2019, one pair built a nest, laid eggs inside, and incubated them. However, the eggs never hatched and were presumed infertile.{{Cite web |last=WRAL |date=May 22, 2019 |title=Attempt to breed Hawaiian crows at nature reserve fails |url=https://www.wral.com/attempt-to-breed-hawaiian-crows-at-nature-reserve-fails/18403649/ |archive-url=https://web.archive.org/web/20190522181419/https://www.hawaiinewsnow.com/2019/05/22/attempt-breed-hawaiian-crows-nature-reserve-fails/ |archive-date=May 22, 2019 |access-date=May 30, 2019 |website=WRAL.com |language=en}} Another pair exhibited nest-building behavior, but did not succeed in building a full nest.{{Cite web |title=FIRST NESTING BEHAVIOR OF RELEASED ʻALALĀ, ALMOST TWO YEARS POST-RELEASE |url=https://dlnr.hawaii.gov/alalaproject/2019/05/08/first-nesting-behavior-of-released-%ca%bbalala-almost-two-years-post-release/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}}

As of February 2024, plans are underway to release {{okina}}alalā on Maui, aiming for releases to begin in spring of 2024.{{Cite web |title=Final Environmental Assessment for Release of ʻAlalā On Maui |url=https://dlnr.hawaii.gov/alalaproject/2024/02/21/final-environmental-assessment-for-release-of-%ca%bbalala-on-maui/ |access-date=2024-03-05 |website=dlnr.hawaii.gov |language=en}} Although {{okina}}alalā were known historically to exist only on the island of Hawaii, subfossil evidence has shown that {{okina}}alalā were found on Maui as recently as when humans began occupying the Hawaiian Islands. Because Maui has a similar landscape and plants to Hawaii but does not have any Hawaiian hawks, it is thought that {{okina}}alalā may be able to survive on Maui without a threat which caused the majority of deaths in prior reintroductions.

On December 4, 2024, two females and three males were reintroduced to Maui.{{Cite web |date=2024-12-05 |title=Hawaiian crow that went extinct in the wild decades ago released on Maui |url=https://apnews.com/article/hawaiian-crow-maui-alal-0f2c3ce79f68cd4b5490989f3777b495?utm_source=copy&utm_medium=share |access-date=2024-12-05 |website=AP News |language=en}}{{Cite web |title=Hawaiian crow that went extinct in the wild decades ago released on Maui |url=https://abcnews.go.com/US/wireStory/hawaiian-crow-extinct-wild-decades-ago-released-maui-116470784 |access-date=2024-12-05 |website=ABC News |language=en}}

The Hawaiian crow is a significant symbol in Hawaiian mythology. It is said to lead souls to their final resting place on the cliffs of Ka Lae, the southernmost tip on the Big Island of Hawaii. Native priests named the ʻalalā so during prayer and chants due to its distinctive call.{{cite book|last=Walters|first=Mark Jerome|title=Seeking the Sacred Raven: Politics and Extinction On a Hawaiian Island|publisher=Island Press/Shearwater Books|year=2006|isbn=978-1-61091-107-8}}

==References==

{{Reflist|25em}}

{{Commons}}

{{Wikispecies|Corvus hawaiiensis}}

{{Corvidae|2}}

{{Taxonbar|from=Q247472}}

{{Authority control}}

Category:Mauna Loa

Category:Corvus

Category:Endemic birds of Hawaii

Category:Biota of Hawaii (island)

Category:Extinct in the wild biota of Oceania

Category:Birds described in 1848

Category:ESA endangered species

Category:Taxa named by Titian Peale