# Crow — Facts, Threats & Conservation

*Corvus*

> A crow is a medium-to-large, mostly black bird of the genus Corvus, part of the corvid family that includes ravens and jays. Found on most continents, crows are among the world's most intelligent birds — using tools, solving problems and recognising individual human faces.

**IUCN status:** Varies by species; common crows Least Concern (IUCN)  ·  **WARN range:** North America, Europe, Asia, Africa, Australia

## Quick facts
| Fact | Value |
| --- | --- |
| Common name | Crow |
| Genus | Corvus |
| Family | Corvidae (corvids) |
| Number of species | Roughly 45+ species worldwide |
| Range | All continents except South America and Antarctica |
| Diet | Omnivore — insects, seeds, fruit, carrion, scraps |
| Notable trait | Tool use, problem-solving, face recognition |
| Social behaviour | Highly social; often roost in large flocks |
| Typical status | Common species Least Concern; varies by species |
| CITES | Most crow species not CITES-listed |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Aves
- **Order:** Passeriformes
- **Family:** Corvidae
- **Genus:** Corvus

## Conservation status
- **Status:** Varies by species. The familiar common crows — including the American crow (Corvus brachyrhynchos) and the carrion crow (Corvus corone) — are assessed by the IUCN as Least Concern, with several populations stable or increasing. The genus Corvus is large, however, and some island and specialist species are threatened; the Hawaiian crow ('Alala) is among the most endangered birds in the world.
- **Population:** Common species number in the millions globally; no single figure applies to the whole genus.
- **Trend:** Stable or increasing for most common crows; declining for some rare specialist species.
- **Assessed:** Common crows assessed Least Concern in recent IUCN Red List assessments.
- **CITES:** Most crow species are not listed on the CITES appendices.
- Because "crow" spans dozens of species, broad-brush statements can mislead: abundance of common crows sits alongside genuine extinction risk for a handful of rarer relatives.

## Key facts: Crow
- "Crow" refers to birds of the genus Corvus, part of the wider corvid (crow) family.
- Crows are among the most intelligent of all birds, with brain-to-body ratios comparable to some primates.
- Several species make and use tools, plan ahead and solve multi-step problems in experiments.
- Crows recognise individual human faces and can hold a grudge — or a favour — for a long time.
- Common species such as the American and carrion crow are Least Concern and often increasing.
- A few island and specialist crows are threatened, so conservation status varies across the genus.

## What makes crows so intelligent?
Crows possess one of the highest brain-to-body ratios among birds, rivalling that of some non-human primates. This is reflected in behaviour that was once thought uniquely mammalian. In laboratory tests, crows solve multi-step puzzles, choose between tools, and appear to plan for future needs rather than acting only on immediate reward. New Caledonian crows, the most famous tool-makers, fashion hooked twigs and barbed leaf-edges to winkle grubs from crevices, and will even use one tool to obtain another. Beyond tools, crows recognise individual human faces, remember those who have threatened them, and can communicate that information to other crows, including their own offspring. They cache food, track who is watching them and re-hide stores when they suspect a thief is nearby — a behaviour linked to perspective-taking. This combination of memory, social learning and flexible problem-solving is why crows are studied so intensively by scientists interested in how intelligence evolves. Importantly, much of this cleverness is practical: it helps crows exploit an enormous range of foods and habitats, from rubbish-strewn cities to remote forests, making them one of the most adaptable bird groups on the planet.

## Where do crows live and what do they eat?
Crows occur across North America, Europe, Asia, Africa and Australasia, occupying almost every habitat from coastal cliffs and open farmland to dense woodland and busy city centres. The genus is conspicuously absent only from South America and Antarctica. This wide range reflects an unfussy, opportunistic diet: crows are omnivores that eat insects, worms, seeds, grain, fruit, eggs, small animals, carrion and human food waste. Their adaptability around people is a major reason familiar species have flourished while many specialist birds decline. Most crows are highly social. Many roost communally, sometimes in flocks numbering thousands, and species such as the rook nest in colonies. Outside the breeding season, large gatherings offer warmth, safety and shared information about where food can be found. Crows are also famously vocal, with a varied repertoire of caws, rattles and clicks used to signal alarm, defend territory and keep contact within the group. Some can even mimic sounds, including elements of human speech in captivity. This blend of dietary flexibility, sociality and intelligence allows crows to live alongside humans more successfully than almost any other wild bird.

## Are crows a single species, and are they endangered?
"Crow" is not one species but a common name for many birds in the genus Corvus, which holds roughly four to five dozen species depending on how they are classified. The same genus also contains ravens, rooks and jackdaws, so the line between a "crow" and a "raven" is more about naming tradition than strict biology. The familiar large black crows of the Northern Hemisphere — the American crow in North America and the carrion and hooded crows across Eurasia — are all assessed by the IUCN as Least Concern, and several are stable or increasing thanks to their comfort around farmland and towns. Because the genus is so large and widespread, conservation status varies considerably. While the common crows are abundant, a number of island-dwelling and habitat-specialist species are far more vulnerable: the Hawaiian crow, for example, is among the most threatened birds in the world. Most crows are not listed on CITES, reflecting that they are not generally traded at levels of concern, though the threatened specialists need targeted protection of their shrinking habitats.

## Crow vs Raven: how to tell them apart
| Feature | Crow | Raven |
| --- | --- | --- |
| Size | Smaller, pigeon-to-medium | Larger, up to buzzard-sized |
| Call | Sharp, repeated "caw" | Deep, hoarse "cronk" or croak |
| Tail in flight | Fan-shaped, rounded | Wedge or diamond-shaped |
| Bill | Slimmer, neat | Heavier, with shaggy throat feathers |
| Typical grouping | Often seen in flocks | Usually in pairs |
| Flight | Steady wingbeats | Soars and tumbles more readily |

## What WARN does
World Animal Rescue Network does not run field projects dedicated specifically to crows, which are widespread and, in their common forms, not threatened. This guide is part of WARN's free educational work to help people understand and value wildlife. The habitat loss, persecution and pollution that threaten the rarer crows of the world are the same pressures bearing down on the animals WARN does protect in its partner countries — so caring about crows is part of caring about the wider web of life.

If crows have ever made you look twice, you can help WARN keep teaching people to see wildlife with the same curiosity.

## Frequently asked questions: Crow
### What is the difference between a crow and a raven?
Both are members of the genus Corvus, so the distinction is partly traditional. In general, ravens are larger, with heavier bills, shaggy throat feathers and a deeper, croaking call, and they soar with a wedge-shaped tail. Crows are smaller, caw rather than croak, and have a fan-shaped tail in flight. Behaviourally, crows are more often seen in flocks, while ravens tend to travel in pairs.

### How intelligent are crows really?
Remarkably so. Crows have brain-to-body ratios comparable to some primates and show abilities once thought uniquely mammalian. They make and use tools, solve multi-step puzzles, plan for the future, recognise individual human faces and remember them for years, and even teach information to other crows. Some appear to understand that other individuals can see what they cannot, a hallmark of advanced social cognition.

### Do crows remember human faces?
Yes. Studies have shown that crows can learn to recognise specific human faces, particularly those of people who have threatened or trapped them. They remember these faces for a long time, scold the individuals when they reappear, and can pass the information to other crows, including their young. Crows also remember people who treat them kindly and may bring small objects in apparent return.

### What do crows eat?
Crows are opportunistic omnivores with an extremely varied diet. They eat insects, earthworms, seeds, grain, fruit and nuts, along with carrion, eggs, nestlings and small animals. In towns and cities they readily scavenge human food waste. This dietary flexibility is one of the main reasons common crows are so widespread and abundant, able to find food in farmland, forest, coastline and city centre alike.

### Are crows endangered?
Most familiar crows are not. Common species such as the American crow and the carrion crow are listed by the IUCN as Least Concern, and several are stable or increasing. However, the genus Corvus contains many species, and conservation status varies. Some island and habitat-specialist crows are threatened — the Hawaiian crow, for instance, is one of the world's rarest birds and has needed intensive recovery efforts.

### Why do crows gather in large flocks?
Crows are highly social and many roost communally, sometimes in gatherings of thousands, especially outside the breeding season. Large roosts offer safety in numbers, shared warmth on cold nights and opportunities to exchange information about good feeding sites. Some species, such as the rook, also nest together in colonies. This sociality, combined with their intelligence, helps crows thrive in a wide range of environments.

## Sources
- [Crow — Wikipedia](https://en.wikipedia.org/wiki/Crow)
- [Corvus (genus) — Wikipedia](https://en.wikipedia.org/wiki/Corvus)
- [American crow — Wikipedia](https://en.wikipedia.org/wiki/American_crow)
- [Carrion crow — Wikipedia](https://en.wikipedia.org/wiki/Carrion_crow)
- [American crow — Encyclopaedia Britannica](https://www.britannica.com/animal/American-crow)
- [IUCN Red List](https://www.iucnredlist.org/)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/crow