Tag Archives: crow

The 45 Crow Species

It’s been a while…a bit over two years in fact. I completed my doctorate and had to spend a few years figuring out the next stages in my life and how I fit in the world. I’m still working on that second part, but things are a bit more stable in general. I now teach at a STEM school that I love (getting oriented with teaching secondary school took up ALL my available time) and I just got back from helping out with the Mariana Crow project on Rota/Luta this summer. I got some inspiring words there to continue with my blog, even though I often wonder if it’s having much of an impact. Thing is, corvids in general are still a passion of mine and continuing to communicate to the public about them is important to me, so I want to carry on.

Enough about my life, this is a blog post meant to help make people aware that there are ~45 species of crows (the genus Corvus). I find most people think there is a crow, raven, rook, and jackdaw, and that’s it. No, my friends, there are many different species of large, black Corvids out there and I’d like to introduce you to them by telling you what their names mean, where they are found, and their closest relatives. In an effort not to reinvent the wheel, I will link to information pages already built about each species. Some species we know a lot about and some species have only been documented a handful of times. I will also group them based on region and their closest relatives, because I’m that kind of a dork.  Note that Corvus literally means “crow/raven” so the meanings of each name will be the species designation (the second word in the scientific name). I will also list how many subspecies each species has, but will not specifically spell them out; those can be found in the associated links. Finally, the word “raven” does not actually denote a related group, it’s just a word used for some of crow species.

A few fun facts before we get started:

*Some systematics ornithologists think the two species of jackdaws should be put in their own genus apart from other crows, genus Coloeus.

*Some systematic ornithologists also want to see the thick-billed and white-necked ravens put into their own genus apart from other crows, genus Corvultur.

*The largest bird in genus Corvus, also being the largest corvid, is the thick-billed raven, weighing a whopping 1.5 kg (3.3 lbs).

*The smallest bird in genus Corvus is the Daurian Jackdaw at a mere ~120 g (0.26 lb).

*Most species of crows are found in the Asian region. This is because the genus originally evolved in this region and radiated across the world from there!

*Crows are found on all continents EXCEPT South America and Antarctica. It’s thought that they never expanded into South America because the toucans had already filled the niche that crows would have taken.

*Some of the most endangered species of birds on the planet are in genus Corvus, including the Banggai crow (<250 individuals estimated left), Mariana crow (<200 individuals estimated left), and the Hawaiian crow (extinct in the wild, with the only extant populations, around 125 individuals, in breeding/recovery facilities).

Without further ado, below are listings for the ~45 crow species currently recognized. Note that I say “currently” because with new data come new species elevations or demotions to subspecies, which may change soon after this post (for example, the Mesopotamian crow is often treated as a subspecies of hooded crow, but sometimes as its own species). Please click the photos to go to their original source.

  • Daurian Jackdaw
    • Scientific Name: Corvus dauuricus
    • Meaning: Comes from the Dauria region of Siberia, though the bird has a broader range than just Dauria.
    • Where in the World: East Asia
    • Closest Relative: Western Jackdaw
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Daurian Jackdaw photo by Sergey Yeliseev.

  • Western Jackdaw (Eurasian Jackdaw)
    • Scientific Name: Corvus monedula
    • Meaning: “to eat money” and is the literal Latin word for the jackdaw. It comes from a Greek myth where the greedy Arne of Thrace (a mythological princess) was turned into a jackdaw after betraying her country to Minos of Crete, for gold, and made to forever be attracted to gold or shiny objects.
    • Where in the World: Europe, Central Asia, and the Middle East
    • Closest Relative: Daurian Jackdaw
    • Number of Subspecies: 4
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Western jackdaw photo by “hedera.baltica”

  • Jamaican Crow
    • Scientific Name: Corvus jamaicensis
    • Meaning: “Of Jamaica”, referring to them being endemic to and only found on Jamaica.
    • Where in the World: Jamaica
    • Closest Relative: White-necked Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Jamaican crow photo found on Geocaching.com

  • White-Necked Crow
    • Scientific Name: Corvus leucognaphalus
    • Meaning: “White mouth” which may just refer to the white feather bases on the neck/throat region of the crow. The common name is misleading as the bird is entirely black, which non-visible white feather bases. The most unique thing with these crows are their beautiful red-orange eyes!
    • Where in the World: Hispaniola, now extinct on Puerto Rico
    • Closest Relative: Jamaican Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      White-necked crow photo by “ZankaM”

  • Cuban Crow
    • Scientific Name: Corvus nasicus
    • Meaning: “Large-nosed”, referring to the bill.
    • Where in the World: Cuba and Caicos Islands
    • Closest Relative: Jamaican and White-necked Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Cuban crows photo by Dubi Shapiro.

  • Black Crow (Cape Crow)
    • Scientific Name: Corvus capensis
    • Meaning: Named for the Cape of Good Hope in Africa where they are typically found.
    • Where in the World: East-central and Southwest Africa
    • Closest Relative: Not well resolved, but right now best connected to the Fish, Sinaloa, Tamaulipas, Palm, and Cuban Crow lineage.
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Black crow photo by Dave Curtis

  • Sinaloa Crow
    • Scientific Name: Corvus sinaloae
    • Meaning: Named for the Sinaloa region of Mexico.
    • Where in the World: Western Mexico
    • Closest Relative: Tamaulipas (they used to be lumped together as the “Mexican Crow”) and Fish Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Sinaloa crow photo by Petr Myska.

  • Tamaulipas Crow
    • Scientific Name: Corvus imparatus
    • Meaning: Means “unprepared or unprovided”, and I’m unsure why they got this designation.
    • Where in the World: Eastern Mexico into Southern Texas (USA).
    • Closest Relative: Sinaloa (they used to be lumped together as the “Mexican Crow”) and Fish Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Tamaulipas crow photo by Luis Enrique Andrade.

  • Fish Crow
    • Scientific Name: Corvus ossifragus
    • Meaning: “Bone breaker”, which may come from them eating carrion.
    • Where in the World: Eastern North America
    • Closest Relative: Tamaulipas and Sinaloa Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase, All About Birds

      Fish crow photo by Paul Tavares

  • Palm Crow
    • Scientific Name: Corvus palmarum
    • Meaning: “Of palm trees” relating to the trees they are often seen in.
    • Where in the World: Cuba and Hispaniola
    • Closest Relative: Fish, Sinaloa, and Tamaulipas Crows
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Palm crow photo by Dax M. and Roman E.

  • Hawaiian Crow/ʻAlalā (EXTINCT IN THE WILD)
    • Scientific Name: Corvus hawaiiensis
    • Meaning: “From Hawai’i”
    • Where in the World: Extinct in the wild, but endemic to Hawai’i. Found in captive rearing facilities on Hawai’i with ongoing efforts to re-introduce them into the wild.
    • Closest Relative: Rook (oddly enough)
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, AvibaseʻAlalā Project

      Hawaiian crow photo from San Diego Zoo Nooz.

  • Rook
    • Scientific Name: Corvus frugilegus
    • Meaning: “Crop-picking or fruit eating” from rooks commonly being found in farmland.
    • Where in the World: All across Eurasia and introduced to New Zealand.
    • Closest Relative: Hawaiian Crow (oddly enough)
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Rook photo by Brian Snelson.

  • Dwarf Raven (Somali Crow)
    • Scientific Name: Corvus edithae
    • Meaning: Named for Edith Cole, a British botanist and entomologist in Somaliland, Africa.
    • Where in the World: Eastern Central Africa
    • Closest Relative: Pied Crow (they sometimes naturally hybridize) and Brown-Necked Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Dwarf raven photo by Marco Valentini.

  • Pied Crow
    • Scientific Name: Corvus albus
    • Meaning: “White”, for the white patch prominent on the crow.
    • Where in the World: Southern Africa and parts of Central Africa.
    • Closest Relative: Dwarf Raven (they sometimes naturally hybridize) and Brown-necked Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Pied crow photo by Krzysztof Blachowiak.

  • Brown-necked Raven
    • Scientific Name: Corvus ruficollis
    • Meaning: “Red or ruddy necked” referring the the reddish-brown plumage on the head, neck, and chest in the species.
    • Where in the World: Northern Africa and the Middle East.
    • Closest Relative: Pied Crow and Dwarf Raven
    • Number of Subspecies: 2 (maybe)
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Brown-necked raven photo by Daniele Occhiato.

  • Fan-tailed Raven
    • Scientific Name: Corvus rhipidurus
    • Meaning: Literally means “fan-tailed” referring to the shape of their unusually short tail in flight.
    • Where in the World: Parts of Northern Africa and the Arabian Peninsula
    • Closest Relative: Pied Crow, Dwarf Raven, and Brown-necked Raven
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Fan-tailed raven photo by Joniec Naturalnie.

  • White-necked Raven
    • Scientific Name: Corvus albicollis
    • Meaning: Literally means “white-necked” referring to the white patch on the back of this species’ neck.
    • Where in the World: Central down through Southern Africa
    • Closest Relative: Thick-billed Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      White-necked ravens photo by buchert.

  • Thick-billed Raven
    • Scientific Name: Corvus crassirostris
    • Meaning: Meaning “thick or heavy bill” referring to this species’ unusually thick and massive bill.
    • Where in the World: Ethiopia, Africa
    • Closest Relative: White-necked Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Thick-billed raven photo by Mike Barth.

  • Chihuahuan Raven
    • Scientific Name: Corvus cryptoleucus
    • Meaning: Means “hidden white” because, like the white-necked crow, they have very white bases to their feathers, though these bases are usually hidden with the bird looking entirely black.
    • Where in the World: Mexico and the Southern Interior USA
    • Closest Relative: Northern Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, AvibaseAll About Birds

      Chihuahuan raven photo by Rick and Nora Bowers.

  • Northern Raven (Common Raven)
    • Scientific Name: Corvus corax
    • Meaning: Means “to croak”, referring to the sound they make, and is synonymous with the bird itself.
    • Where in the World: A Holarctic species, meaning they are found everywhere in nearly the entire Northern Hemisphere
    • Closest Relative: Chihuahuan Raven, Fan-tailed Raven, Pied Crow, and Brown-Necked Raven
    • Number of Subspecies: 12 (including one that had a naturally-occurring piebald morph found in the Faroe Islands, now extinct, Corvus corax varius morpha leucophaeus)
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, AvibaseAll About Birds

      Northern raven photo by Jennifer Campbell-Smith (me).

  • Hooded Crow
    • Scientific Name: Corvus cornix
    • Meaning: Another word that literally means “crow”.
    • Where in the World: Most of Europe, the Middle East, and Western Asia
    • Closest Relative: Carrion Crow (sometimes still lumped as a subspecies of Carrion Crow)
    • Number of Subspecies: 2 (maybe)
    • Info Links: Handbook of the Birds of the World, Wikipedia, Avibase

      Hooded crow photo by Luboš Mráz.

  • Carrion Crow
    • Scientific Name: Corvus corone
    • Meaning: “To croak” and also serves as another word that simply means “crow”.
    • Where in the World: Western Europe and Asia.
    • Closest Relative: Hooded Crow
    • Number of Subspecies: 5 to 6 (depending on the hooded crow’s status as species or subspecies at the time)
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Carrion crow photo by Aurélien Audevard.

  • Collared Crow
    • Scientific Name: Corvus torquatus or Corvus pectoralis
    • Meaning: Torquatus means “collar or torque” (a piece of metal neck jewelry) referring to the white markings around the neck. Pectoralis means “of the breast” referring also to the white markings that extend across the breast of the bird.
    • Where in the World: Eastern China
    • Closest Relative: Hooded and Carrion Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Collared crow photo by Charles Lam.

  • Northwestern Crow
    • Scientific Name: Corvus caurinus
    • Meaning: “Northwest wind” referring to the crows being found in the Pacific Northwest of North America
    • Where in the World: Along the coasts of the Pacific Northwest, North America.
    • Closest Relative: American Crow (used to be a subspecies of American crow; scientists still argue over this)
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, AvibaseAll About Birds

      Northwestern crow photo by “Nebrot”.

  • American Crow
    • Scientific Name: Corvus brachyrhynchos
    • Meaning: “Short bill or nose” referring to their relatively petite bill.
    • Where in the World: North America
    • Closest Relative: Northwestern Crow
    • Number of Subspecies: 3
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase, All About Birds

      American crow photo by Jennifer Campbell-Smith (me).

  • White-billed Crow
    • Scientific Name: Corvus woodfordi
    • Meaning: Named for Charles Woodford, a British naturalist.
    • Where in the World: Islands of Choiseul, Isabel, and Guadalcanal in the Northern Solomon Islands
    • Closest Relative: Bougainville and Brown-Headed Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      White-billed crow photo by Lars Petersson.

  • Bougainville Crow
    • Scientific Name: Corvus meeki
    • Meaning: Named for Albert Meek, and English explorer.
    • Where in the World: Islands of Bougainville and Shortland in the Solomon Islands
    • Closest Relative: Unknown, but likely the White-billed Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Bougainville crow illustration (no known photos of a live bird!) from the Handbook of the Birds of the World.

      Bougainville crow skin from the American Museum of Natural History photo by Jennifer Campbell-Smith (me).

  • Brown-headed Crow
    • Scientific Name: Corvus fuscicapillus
    • Meaning: “Dusky or brown head” for the dark brown feathers on their heads and necks.
    • Where in the World: Northwest New Guinea and the Aru Islands
    • Closest Relative: White-billed Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Brown-headed crow juvenile photo by Mehd Halaouate.

      Brown-headed crow adult study skin photo from the American Museum of Natural History by Jennifer Campbell-Smith (me).

  • Long-billed Crow
    • Scientific Name: Corvus validus
    • Meaning: “Strong or stout” for their unusually long bills.
    • Where in the World: Moluccan islands of Morotai, Obi, and Halmahera
    • Closest Relative: Grey Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Long-billed crow photo by Yann Muzika.

  • Grey Crow
    • Scientific Name: Corvus tristis
    • Meaning: “Sad or gloomy” possibly referring to their dingy (but unique!) grey plumage.
    • Where in the World: New Guinea
    • Closest Relative: Long-billed Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Grey crow photo by Brian J. Coates.

  • Forest Raven
    • Scientific Name: Corvus tasmanicus
    • Meaning: Found in Tasmania and though they occur elsewhere in Australia, the specimen that was originally described probably came form Tasmania.
    • Where in the World: Tasmania and southern mainland Australia
    • Closest Relative: Little and Australian Ravens
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Forest raven photo by Paul van Giersbergen.

  • Little Raven
    • Scientific Name: Corvus mellori
    • Meaning: Named for Joseph Mellor, an English chemist.
    • Where in the World: Southeast Australia
    • Closest Relative: Australian Raven
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Little raven photo by Toby Hudson.

  • Australian Raven
    • Scientific Name: Corvus coronoides
    • Meaning: “Resembling a carrion crow” likely given when British explorers first saw that it was a black corvid in Australia, so they named it according to a bird back home that they thought it looked like, the carrion crow.
    • Where in the World: South and Eastern Australia
    • Closest Relative: Little Raven
    • Number of Subspecies: 2
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Australian raven photo by Peter Strauss.

  • Torresian Crow
    • Scientific Name: Corvus orru
    • Meaning: Unsure, but likely based on a Papuan name.
    • Where in the World: Australia and New Guinea as well as surrounding islands
    • Closest Relative: Bismark and Little Crows
    • Number of Subspecies: 3
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Torresian crow photo by David Taylor.

  • Bismarck Crow
    • Scientific Name: Corvus insularis
    • Meaning: “Insula of an island” likely from them inhabiting islands.
    • Where in the World: Bismarck Archipelago
    • Closest Relative: Torresian Crow (previously a subspecies of Torresian Crow)
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Bismarck crow photo by Lars Petersson.

  • Little Crow
    • Scientific Name: Corvus bennetti
    • Meaning: Named for George Bennett, a British biologist.
    • Where in the World: Australia
    • Closest Relative: Torresian Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Little crow photo by Don Hadden.

  • Banggai Crow (CRITICALLY ENDANGERED)
    • Scientific Name: Corvus unicolor
    • Meaning: “Plain or uniform” probably referring to their all black coloration.
    • Where in the World: Island of Banggai
    • Closest Relative: Piping and Slender-Billed Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Banggai crow photo by Philippe Verbelen.

  • Piping Crow
    • Scientific Name: Corvus typicus
    • Meaning: The “type” or “typical” crow, which is interesting considering their entire torso and upper neck is white!
    • Where in the World: Island of Sulawesi
    • Closest Relative: Slender-billed and Banggai Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Piping crow photo by Pete Morris/Birdquest.

  • Violaceous Crow (Violet Crow)
    • Scientific Name: Corvus violaceus
    • Meaning: “Violet-colored” from the violet sheen on their plumage.
    • Where in the World: Philippines and Moluccas
    • Closest Relative: Slender-billed Crow (used to be a subspecies of Slender-billed Crow)
    • Number of Subspecies: 4
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Violaceous crow photo by Dubi Shapiro.

  • Slender-Billed Crow
    • Scientific Name: Corvus enca
    • Meaning: Enca is the Javanese word for “crow”.
    • Where in the World: Malaysia, Sumatra, Java, Borneo, and some other nearby islands
    • Closest Relative: Violaceous, Piping, and New Caledonian Crows
    • Number of Subspecies: 7
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Slender-billed crow photo by Rob Hutchinson.

  • New Caledonian Crow
    • Scientific Name: Corvus moneduloides
    • Meaning: “Resembling a jackdaw” because again, it reminded European explorers of a bird back home, so they just gave it a name that literally meant “kind of like that bird back home, the jackdaw”.
    • Where in the World: Island of New Caledonia and introduced to the nearby island of Maré.
    • Closest Relative: Slender-billed Crow
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      New Caledonian crow photo by “Corvus moneduloides”.

  • Flores Crow (ENDANGERED)
    • Scientific Name: Corvus florensis
    • Meaning: Named for the island of Flores in the Sundas of Indonesia.
    • Where in the World: Flores, within the Sundas of Indonesia
    • Closest Relative: Likely Slender-billed, Banggai, and Piping Crows
    • Number of Subspecies: 0
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Flores crow photo by Indonesia Tourism.

  • Large-billed Crow
    • Scientific Name: Corvus macrorhynchos
    • Meaning: “Long/large bill/nose” referring to their large bills.
    • Where in the World: Eastern Asia, Indian Himalayas, Philippines, and a number of East Indian Islands.
    • Closest Relative: House and Mariana Crows
    • Number of Subspecies: 11 (some of which may be elevated to species status soon or have been in the past, such as the jungle crow)
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      Large-billed crow photo by Tushar Bhagwat.

  • Mariana Crow (CRITICALLY ENDANGERED)
  • House Crow
    • Scientific Name: Corvus splendens
    • Meaning: “Brilliant or glittering” likely referring to the slight iridescent sheen on their black feathers.
    • Where in the World: India, but introduced to ports in the Middle East and Africa.
    • Closest Relative: Large-billed and likely Mariana Crows
    • Number of Subspecies: 4
    • Info Links: Handbook of the Birds of the World, Wikipedia, IUCN, Avibase

      House crow photo by Peter Vercruijsse.

       

Information in this post is a result of research utilizing the sources linked, but mostly the following sources:

Luta Bird Conservation

I’ve mentioned in previous posts that some crows are among the most endangered birds on the planet, such as the ʻAlalā, or Hawaiian Crow (Corvus hawaiiensis) and the Mariana crow, or Aga (Corvus kubaryi).  A colleague and friend, Sarah Faegre was kind enough to send me information on the new non-profit she and Phil Hannon have created for the conservation of Mariana crows.  I asked Sarah to please send me information so I could spread the word, especially since they are doing incredible work with the local community to spread the message of conservation and coexistence.  Here is what Sarah had to say:

______________________________________________________________________

Luta Bird Conservation Inc. (LBC) is a 501(c)3 nonprofit, created by Sarah Faegre and Phil Hannon to raise funds to conserve endangered birds and their habitats by working with the human communities surrounding them. LBC’s first project is the conservation of the Aga (Mariana Crow, Corvus kubaryi) on Rota, Commonwealth of the Mariana Islands (CNMI). Specifically, LBC’s aim is to use education and community outreach to involve local people directly in research and management of the Aga on Rota. The Aga is the only crow species in Micronesia and is endemic Rota and Guam, to the two southernmost islands of the Mariana Islands archipelago. Once common on both Guam and Rota, the Aga was extirpated from Guam by the Brown Tree Snake (Boiga irregularis). The Aga now exists on only Rota, an 86-square-kilometer island. Rota does not have snakes, but other problems, such as feral cats, human persecution and habitat changes (among other possible causes) have caused a steep decline on Rota as well. As of 2014, an estimated 130 individuals remain on this small island (and in the world) and the population is still declining.

The majority of the funding for Aga conservation comes from the US Fish and Wildlife Service and the CNMI Department of Lands and Natural Resources. However these funds are limited and, in particular, education and community involvement has been underutilized. Community outreach and education are extremely important; without the support of the local people the Aga is unlikely to survive. Currently, a high percentage of the local population has a negative view of the Aga, due to land-use conflicts and due to conflicts between federal and state-run governmental programs. LBC’s goals include working in the schools to help kids understand the value of the Aga and to encourage them to take pride in their native animals by working with biologists and educating their peers.

Sarah Faegre taught with fellow biologist Andria Kroner (and Sunny, the captive Aga) on behalf of Luta Bird conservation

Many mainland residents may think that crows are everywhere and shouldn’t need much extra help to survive alongside people. In fact, these beliefs are also common among the local population on Rota, due to the lack of education about the uniqueness of Rota’s Aga. The the appearance may be similar to the casual observer, the Aga is quite different from the crows of the mainland US. Aga do not gather in large groups, but stick to their family unit and small home range area in the jungle. They have unique foraging abilities, such as opening hard-shelled hermit crabs with their beak. Since Aga evolved without predators for thousands of years, they lost their vigilance behaviors and are now unable to protect themselves from introduced predators.

Sunny, the Aga, acting as an ambassador for his species to a classroom of children.

LBC’s recent activities include raising funds for Aga T-shirts that kids and adults can wear, in hopes that we can spread knowledge and pride about this unique crow species. The painting used for the T-shirt was created by artist, biologist and Corvid expert Jennifer Campbell-Smith. The painting depicts an adult Aga (foreground) and fledgling Aga (background). The adult is cracking open a hermit crab while the fledgling observes. The design surrounding the painting depicts some of the Aga’s common food items and also the Brown Tree Snake, the invasive species that resulted in the extirpation of the Aga (and other native birds) from Guam. Luckily the Brown Tree Snake is not present on Rota and with the help of the local community, we still have time to save the species. The Chamorro phrase at the top of the T-shirts translates to: “Make Rota Beautiful”, which a common motto of Rota island.

 

Photo copyright Jolyon Troscianko

Regarding Tool Manufacture and New Caledonian Crows

I tend to leave incidental posts, responses to Tumblr posts, and Tumblr replies to the Tumblr incarnation of this blog, trying to keep this official Coyot.es space more for original content and longer posts.  However, this reply was lengthy enough and contained enough original material beyond the initial reply that I thought it would be good to post it here.

This comment is a reply to my correction of the source page for the incorrect NowYouKno “fact” on Tumblr.

I appreciate you pointing out this distinction, though manufacture versus use is sort of a continuum, depending on how we are defining “manufacture”.  It is true that New Caledonian crows are amazing tool makers (something I give lectures about on a nearly annual basis when I talk about animal culture), but more than three species make tools.  Chimpanzees, of course, are tool makers, along with documentation of manufacture in orangutans, mandrills, and Asian elephants.  This is leaving out animals that develop tools or can be taught to develop tools in captivity (ex. bonobos, hyacinth macaws, and a Goffin’s cockatoo, just to name a few).  Also depending on how complex the manufacture, gorillas have been observed breaking off large sticks for stabilization, woodpecker finches have to break off cactus spines to use them (and more recently they are modifying non-native blackberry spines), and bottle-nosed dolphins have to select and break sponges off their substrate to use them.  I still assert that we will probably find a lot more tool use and manufacture in the wild, the more chances we get to observe different species in the wild.  There are certainly many anecdotal and incidental observations of many more species creating and using tools.  However, what you have to keep in mind is that if an animal gets along fine without making and using tools, then there’s not point in them doing so.  Tool manufacture and modification, while really cool to us, isn’t always necessary for other animals.  In chimpanzees and humans, for example, tool use is integral in how we forage and exist in the world, but for other species tool manufacture and use may only be needed on occasion, when a situation calls for it.

In the case of New Caledonian crows, they, like woodpecker finches, live in places that lack woodpeckers.  This is significant because it leaves open the niche that specializes in locating, removing, and eating wood boring insects.  Rather than spending the time to evolve physical adaptations to do this (like woodpeckers have) these two species use tools to the same ends.  Arguably, there is a distinction between woodpecker finches (which are actually most likely in the tanager family, despite the common name) and New Caledonian crows when it comes to the cognitive department.

What happens when nature takes a bird, already a part of a large-brained, cognitively complex genus of birds (Corvus) and puts it on an island that has a goldmine of a niche to fill?  You get the incredible New Caledonian crow (Corvus moneduloides).


(Photo copyright Jolyon Troscianko)

Drs. Russell Gray and Gavin Hunt observed these birds in the wild manufacturing and using tools.  The earliest documented account of tool us in NC crows was by an explorer who reported the use of anvil sites to crack open nuts and snails in 1882.  In 1909 Le Goupils observed NC crows probing a dead log with a stick-tool (reported in 1928) and Orenstein gave a more detailed report on crow tool-use in 1972, but it was Hunt (his first study published in 1996) and Gray who brought attention to these incredible corvids and who still do work on them today.  In 2000, birds were taken from New Caledonia and sent to England to be studied by Alex Kacelnik‘s Behavioral Ecology Research Group (BERG) at the University of Oxford.  Two of these birds were Betty and Abel.  Betty blew the minds of the world when she spontaneously bent a metal wire into a hook to retrieve food after Abel made off with the hooked tool.

Part of the reason the NC crows were brought into captivity by Kacelnik was to see if the tool behaviors were innate or due to complex cognition and problem solving, or even if they were cultural as Gray and Hunt suggested.  The BERG found that young NC crows, with no training or example, had a proclivity for tearing materials and probing holes with other objects.

So if the birds could manufacture and use tools completely on their own, what makes them more noteworthy than woodpecker finches or other animals that innately use tools?  What makes them rival and often exceed chimps in the cognitive department?  Tradition, the understanding of the functional properties of their tools, innovative use of tools, and cumulative tool evolution all combine to make NC crows stars in the world of animal cognition.

Gray and Hunt found that different tool types were being used by NC crows in different regions of New Caledonia.  These tool types were not reproduced by Kacelnik’s captive crows, which lends more support to those tools’ forms being based on a tradition, or culture, rather than just a genetic ability to make them (after all, humans babble as a precursor to language).  NC crows also understand the functional properties of the tools they use and make.  They use a range of materials and techniques for making tools, demonstrating that it’s the crow that decides on the tool, not the material.  Understanding of the functional properties of their tool was also demonstrated by Betty bending the wire, and again in further experiments.  One experiment even showed that the crows could determine the rigidity of tools that would be appropriate for a task.  Finally, NC crows show cumulative tool evolution, something we humans still clung to as unique to us.  Cumulative tool evolution is the ability to take a tool and modify it to a different or better function and build on previous technology.  The tools that were created by precisely snipping and tearing Pandanus spp. tree leaves (the form of which were not replicated by Kacelnik’s captive birds) showed strong evidence of enhancement over time.  Hunt and Gray found and compared tool types and their functions from all over the island, including historical records of negatives left in leaves up to four years old.  Their findings suggest that the Pandanus tools have had significant improvement on their shape and functionIf this doesn’t blow your mind, I don’t know what will!!

Researchers have since found evidence of cumulative tool evolution in chimpanzees as well.  And thus, the battle for most cognitively complex non-human tool user rages on between chimpanzees and NC crows.  In recent years, the ability to use tools to get tools (or meta-tool use) has been a focus of attention, with several studies demonstrating that NC crows can figure out what tool they need for a task, and use other tools to get the appropriate tool (here’s a video).  There have also been studies into the brains of New Caledonian crows, among other cognitive work that shows that these birds are truly complex animals that blur the line between human and non-human intelligence and understanding of the world around them.  Click here for The University of Auckland’s page on NC Crow research still run by Gray and Hunt, and here for a list of their publications which go well beyond what I’ve related to you here.  Both researchers at The University of Auckland and The University of Oxford are continuing work on these birds, so you should keep an eye out for their continued publications and findings.

I’m a huge fan of NC crows, if it wasn’t apparent.  One of my most treasured possessions is a genuine Pandanus tool made by a New Caledonian crow.  I even had one of Hunt and Gray’s papers signed (how big of a nerd can I be?), but that was sadly destroyed in a flood.  It is a life goal to make it to New Caledonia and observe these birds in the wild.  Thank you Pamela Turner for giving me an excuse to blather about NC crows and I hope all of you who read this now appreciate them as much as I do!

Australian Crows – Guest Post by Matthew Brown!

This is a special guest post by fellow corvid researcher Matthew Brown. Matt is a PhD candidate at Griffith University’s Environmental Futures Research Institute in Brisbane, Queensland and studies Torresian crows (Corvus orru).  I asked him to write about Australian crows and his research for this blog and he was kind enough to do so.  Enjoy!!
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For the past three years I have been studying one of the most common birds on the Australian continent, the Torresian crow. Crows have become extremely common in Australia over the past two decades, nowhere moreso than in the Queensland capital city of Brisbane. A subtropical city of two million people, Brisbane provides enough lawns and rubbish to support enormous populations of crows and other scavengers. Such is the abundance of crows and their interaction with humans so common that the Queensland Government Department of Environment and Heritage Protection has a “Living with Crows” page on its website.

A Torresian crow caught at Griffith University’s Nathan Campus in Brisbane. The crow, 40cm long and approximately 750g, was banded for identification and released.

Five species of corvid exist in Australia, including three sedentary species: the Torresian crow (Corvus orru), Australian raven (C. coronoides) and Forest raven (C. tasmanicus), and two smaller nomadic species, the Little crow (C. bennetti) and Little raven (C. mellori). Only the Torresian crow exists in Brisbane.

Despite having the names crows and ravens, these five species are a monophyletic clade, which means they all come from the same ancestor. So an Australian raven is more closely related to the Torresian crow than to, say the common raven (C. corax) from the Northern Hemisphere. The exception to this being that the Torresian crow also exists in Papua New Guinea, as a separate subspecies.

The five species are best identified by their geographic location, but also their calls. Each species have very distinct, though extremely complex and variable, calls which can’t really be mistaken for each other (with the possible exception of the Australian raven and little raven).

The current theory about how, after crossing over from PNG, the corvids split into five species across Australia is explained in-depth in the late Ian Rowley’s paper “Why five species?

Torresian crows, while territorial, spend the night in permanent communal roosts scattered throughout Brisbane. These vary widely in size, and can contain anything from a few dozen to 200 birds. The roosts are often also shared with rainbow lorikeets and ibis.

All Australian corvids hatch with blue eyes as chicks, then change to the juvenile brown, then the adolescent hazel before finally becoming the adult white with a blue inner ring at about 2 years old. The process is the same for all 5 species, though the exact time of each stage varies. This is the easiest method to tell the juveniles apart from the adults. Early European scientists used to consider them separate species (the brown-eyed crow and the white-eyed crow) before they finally figured it out.

Juvenile crows stay with their parents for approximately six months, though this appears to be highly variable. After leaving, they join what are known as ‘juvenile gangs’, which often congregate around shopping centres or parks, areas with a large amount of human scraps. One of the largest of these gangs permanently live in the South Bank Parklands. The Queensland Government estimates that crows have a 95% infant mortality rate, though those surviving to adulthood (2 years old) can live up to 30 years.

One of the largest permanent juvenile gang sites is the popular South Bank Parklands, likely due to the abundance of human food available.

Compared to the extensive research conducted on New Caledonian crows, American crows, common ravens etc, very little is known about the Torresian crow. Because of this, my studies are focussing predominantly on replicating Northern Hemisphere studies on this species. These include:

In addition, I have already undertaken a study comparing neophobia (a fear of novel objects) in Torresian crows with other non-corvid corvines including butcherbirds, currawongs and Australian magpies. The extreme neophobia present in crows has made working with wild birds very difficult, requiring an extensive familiarisation process. My study of the Torresian crow’s vocalisation system also revealed not only extraordinary diversity in calls, but suggested the presence of a nested hierarchy similar to that deemed present in American crows by researchers in the United States. Professor John Marzluff described crows as likely possessing a basic form of language, and on the surface at least it appears that Torresian crows can match or even surpass their American cousins in this regard.

Torresian crows have already shown some of the remarkable qualities expressed in their overseas cousins. The invasion of North-Eastern Australia by cane toads has been disastrous for all native fauna, except the crow. Crows in Eastern Queensland were first recorded to be flipping toads onto their backs, allowing them to peck at their bellies and avoid the poisonous glands on their backs. Very soon after, much sooner than one would expect, crows as far as Darwin were performing the same behaviour. How the information spread so far so quickly is unknown. Crows have also been reported unzipping school bags and stealing food from children’s lunchboxes, and working as a team to move large carrion off of rural roads, while one acts as a sentry warning of oncoming traffic.

My own observations have confirmed that Torresian crows can recognise friendly or unfriendly human faces and act accordingly, though are extremely wary of all humans that pay them any attention. The infamous crow funerals appear to be present in Brisbane as well, though crows being hit by a car or electrocuted is quite rare.

Crows are a joy to study anywhere in the world, but in Australia there is a level of mystery that makes it all the more rewarding. So little is known about the crow that everything is a new discovery, and provides an intriguing comparison with better-known species from the Northern Hemisphere and in New Caledonia.

Two crows, one banded, participating in the familiarisation process of an experiment at Griffith University’s Nathan Campus.