Hawaiian crow: Difference between revisions

The '''Hawaiian crow''' or '''{{okina}}alalā''' ('''''Corvus hawaiiensis''''') is a species of bird in the crow family, [[Corvidae]], that is currently [[extinct in the wild]], though reintroduction programs are underway. It is about the size of the [[carrion crow]] at {{convert|48|–|50|cm|in|abbr=on}} in length,<ref name=":0" /> but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage and long, bristly throat feathers; the feet, legs, and bill are black.<ref name=":3" /> Today, the Hawaiian crow is considered the most endangered of the family Corvidae.<ref name=":2">{{Cite web|title = Hawaiian crow photo – Corvus hawaiiensis – G117026|url = http://www.arkive.org/hawaiian-crow/corvus-hawaiiensis/image-G117026.html|website = www.arkive.org|publisher = [[Arkive|Wildscreen Arkive]]|access-date = 30 October 30, 2015|archive-url = https://web.archive.org/web/20151120023237/http://www.arkive.org/hawaiian-crow/corvus-hawaiiensis/image-G117026.html|archive-date = 2015-11-November 20, 2015|url-status = dead}}</ref> They are recorded to have lived up to 18 years in the wild, and 28 years in captivity. Some [[Native Hawaiians]] consider the Hawaiian crow an ''[[Aumakua|{{okina}}aumakua]]'' ([[Household deity|family god]]).<ref>{{cite encyclopedia |last1name=":3">Banko, |first1=PaulP. C., |last2=Ball |first2=DonnaD. L. |last3=BankoBall, |first3=Winstonand W. E. |editor-last=PooleBanko |editor-first=A(2020). |date=2002 |title=Hawaiian Crow (''Corvus hawaiiensis''), version 1.0. In |encyclopedia=[[Birds of Norththe AmericaWorld (book)|TheA. BirdsF. ofPoole Northand AmericaF. Online]]B. Gill, Editors). |publisher=Cornell Lab of Ornithology, |url=httpIthaca, NY, USA. <nowiki>https://bnadoi.birdsorg/10.cornell.edu2173/bna/species/648bow.hawcro.01</articles/introduction |access-date=2009-03-20}}nowiki></ref>

The species is known for its strong flying ability and resourcefulness, and the reasons for its various [[Local extinction|extirpations]] are not fully understood. It is thought that introduced diseases, suchintroduced as ''[[Toxoplasma gondii]]''predators, [[avianand malaria]]habitat (''Plasmodium relictum''), and [[fowlpox]],loss were probably significant factors in the species' decline.<ref name="FactSheet">{{citeNational reportResearch |last1=MitchellCouncil |first1=Christen(US) |last2=OguraCommittee |first2=Christineon |last3=Meadowsthe |first3=DwayneScientific |last4=KaneBases |first4=Austinfor |last5=Strommerthe |first5=LauriePreservation |last6=Fretzof |first6=Scottthe |last7=LeonardHawaiian |first7=DavidCrow. |last8=McClungScientific |first8=AndrewBases |date=Octoberfor 1, 2005 |chapter=7:the SpeciesPreservation of Greatestthe ConservationHawaiian NeedCrow. |title=Hawaii'sWashington Comprehensive(DC): WildlifeNational ConservationAcademies StrategyPress |publisher=Department(US); of1992. Land andExecutive NaturalSummary. ResourcesAvailable |location=Honolulu,from: Hawaiʻi |page=c.189 |chapter-url=http<nowiki>https://dlnrwww.hawaiincbi.nlm.nih.gov/wildlifebooks/filesNBK235935/2013</09/CWCS-Full-Document-2005Oct01.pdf |access-date=2009-03-20}}, 16 MB file. Pages are largely unnumbered but entry for "{{okina}}Alalā or Hawaiian Crow" is roughly on page 189.nowiki></ref>

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.<ref>{{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 = 2015-10-October 30, 2015}}</ref> ''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 ''[[Hawaiian hawk|{{okina}}io]]'' (''Buteo solitarius).'' Nesting sites of the ʻalalā received {{convert|600|-|2500|mm|in}} of annual rainfall.<ref name="Recovery">{{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 }}</ref> 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.<ref name=":1" />

The Hawaiian crow was also preyed on by rats and the small Asian mongooses (''[[Urva auropunctata]]''). [[Feral cat]]s 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.<ref>{{Cite web|title = Alala – The Hawaiian Crow {{!}} BirdNote|url = http://birdnote.org/show/alala-hawaiian-crow|website = birdnote.org|access-date = 2015-10-October 30, 2015}}</ref>

The [[Omnivore|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 [[invertebrate]]s such as [[Isopoda|isopods]], [[land snail]]s, and [[arachnid]]s. They feed in a [[woodpecker]] fashion, flaking bark and moss from trunks or branches to expose hidden insects, foraging mostly on ohia and [[Acacia koa|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 [[Ceodes umbellifera|kepau]] and [[Cheirodendron trigynum|olapa]] fruit clusters. Although [[Pittosporum hosmeri|hoawa]] and [[Melicope knudsenii|alani]] fruits have hard outer coverings, crows continue to exert energy prying them open. [[Passerine]] nestlingsNestlings 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]], [[‘elepaio'elepaio]], and [[ʻapapane]]. The {{okina}}alalā also commonly forages on flowers, especially from February through May. Nectar to feed the young areis 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.<ref name=":0">{{Cite journal|title = Foraging Ecology of the Hawaiian Crow, an Endangered Generalist|jstor = 1368918|journal = The Condor|date = May 1, 1986-05-01|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}}</ref>

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.<ref name="Graef">{{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}}</ref><ref name="Rutz">{{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}}</ref><ref>{{cite press release |author=<!--Staff writer(s); no by-line.--> |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, 2016-09-14|access-date=September 15, 2016-09-15}}

The Hawaiian crow has a [[Bird vocalization|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.<ref name=":1">{{Cite web|title = Hawaiian Bird Conservation Action Plan – Hawaiian Crow|url = https://www.pacificrimconservation.org/publications/|website = Pacific Rim Conservation|access-date = 2015-10-October 29, 2015|date = 2013|type = pdf}}</ref> The {{okina}}alalā has at least 24 calls in its repertoire, including [[Alarm signal|alarm calls]], [[contact call]]s, and calls signifying submission or [[Courtship display|courtship]].<ref>{{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}}</ref>

[[File:Corvus_hawaiiensis_medley Corvus hawaiiensis medley.ogg|link=|220x220px]]This is a medley of the different calls the Hawaiian Crow makes.<ref>{{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 = 2015-10-October 30, 2015}}</ref>

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

</ref> 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’aohi'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.<ref>{{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-10date = August 13, 2016|archive-30url = 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}}</ref> 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.<ref name=":1" />

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.<ref>{{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, 2012-09-01|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 }}</ref> The Hawaiian crow has become known as an [[indicator species]]; the disappearance of the {{okina}}alalā indicates serious environmental problems.<ref>{{Cite journal|title = Random Samples|jstor = 2877246|journal = Science|date = 1992-05-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}}</ref>

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 leadingleads to a higher likelihood of [[inbreeding]], which couldreduces resultthe inlikelihood lethalthat deformities.offspring Unlikewill most crows, Hawaiian crows did not adapt wellsurvive to human[[Recruitment presence(biology)|recruitment]]. Persecution by humans is another threat to their survival. Farmers have shot <ref>{{okina}}alalāCite becausejournal they|last1=Flanagan were|first1=Alison believed to disturb cropsM. Illegal|last2=Masuda hunting|first2=Bryce has|last3=Grueber continued|first3=Catherine even after legal protection was granted to the crowsE. |last4=Sutton Humans|first4=Jolene have also caused habitat degradation and [[deforestation]] through agriculture, ranching, logging, and non-native [[ungulate]]sT. Loss|date=August of2021 canopy|title=Moving coverfrom exposes the {{okina}}alalātrends to dangerousbenchmarks predators.by Chicksusing are vulnerable toregression tree-climbing rats and, after they leave their nests,analysis to cats,find dogs,inbreeding andthresholds [[mongoose]]s.<ref>{{Citein web|titlea =critically 'Alalāendangered –bird Pacific Islands Fish and Wildlife Office|url = httphttps://wwwconbio.fwsonlinelibrary.govwiley.com/pacificislandsdoi/fauna10.1111/alalacobi.html13650 |websitejournal=Conservation Biology |language=en www.fws.gov|access-datevolume=35 |issue=4 2015-|pages=1278–1287 |doi=10-29}}<.1111/ref>cobi.13650 Deforestation|pmid=33025666 also increases soil erosion and the spread of [[Invasive species|invasive]] plants and mosquitoesbibcode=2021ConBi.<ref.35.1278F name|s2cid=":1"222182269 |issn=0888-8892}}</ref> This directly relates to the primary cause of the Hawaiian crow's extinction, [[disease]].

=== AvianHabitat malarialoss and hunting ===

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 [[Endangered Species Act of 1973|U.S. federal law]].<ref>{{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}}</ref> By 1994, the populationsoverall population had dwindled to 31 individuals; 8 to 12 were wild and 19 held in captivity.<ref name=":2" /> The only wild-born juvenile produced between 1992–2003 was last seen in 1997.<ref name="Recovery" /> The last two known wild individuals of the Hawaiian crow disappeared in 2002,<ref name=dnh>{{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, 2007-01-08 |archive-url=https://web.archive.org/web/20070927035408/http://www.conbio.org/cip/article74har.cfm |archive-date=2007-09-September 27, 2007 |url-status=dead }}</ref> and the species is now classified as [[Extinct in the Wild]] by the [[IUCN Red List]].<ref name=IUCN/> While someSome 115 individuals remain (as of August 2014)<ref name="CBS8">{{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=2014-08-August 13, 2014}}</ref> in two [[captive breeding]] facilities operated by the [[San Diego Zoo]],. attemptsAttempts 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.<ref>{{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 = 2015-10-October 30, 2015}}</ref>

The {{okina}}alalā has been legally protected by the state of Hawaii since 1931 and was recognized as federally endangered in 1967.<ref name="Recovery" /> 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.<ref name=":1" />

==== ReintroductionCaptive breeding efforts ====

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.<ref>{{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=9781610911078978-1-61091-107-8}}