How smart are crows? - Katharina Brecht

Key Concepts:

• Corvids (crows, ravens, jays, magpies): A family of songbirds known for their intelligence.
• Cognition: Mental processes involved in knowing, learning, and understanding.
• Caching: Storing food for later retrieval.
• Tool Use: Utilizing objects to achieve a goal.
• Social Intelligence: The ability to understand and navigate complex social interactions.
• Pallium: A brain region associated with cognition, found in both birds and mammals.
• Neurons: Basic functional units of the nervous system.

Corvid Intelligence: An Overview

Corvids, including crows, ravens, jays, and magpies, are recognized for their remarkable intelligence, challenging previous assumptions about avian cognitive abilities. This intelligence manifests in various ways, from strategic food acquisition to complex social behaviors.

Food Acquisition and Storage

Corvids exhibit strategic behavior when obtaining food. They are known to ransack trash bins and steal food from other birds. A key aspect of their food-related intelligence is caching, where they store food for later consumption.

• Clark's Nutcracker: A single Clark's nutcracker can scatter approximately 30,000 pine nuts across over 2,000 cache sites and remember their locations for more than nine months.
• Scrub Jays: An experiment showed that scrub jays prioritize caching perishable food (waxworms) over non-perishable food (peanuts) and retrieve them accordingly, demonstrating memory of what they buried and when.
• Future Planning: Scrub jays will bury food when they anticipate its unavailability the next day, indicating an ability to plan for future events.

Social Cognition and Memory

Corvids possess advanced social cognitive abilities, including facial recognition and awareness of death.

• Facial Recognition: Crows can distinguish and remember individual human faces. In one experiment, crows dive-bombed a person wearing a specific mask who had previously trapped and released a crow, but ignored the same person wearing a different mask.
• "Funerals": Crows gather around the bodies of their dead companions and caw, a behavior likened to a funeral. Studies suggest they associate the location of a dead crow with risk and avoid it.

Tool Use and Problem-Solving

Corvids demonstrate impressive reasoning and tool use abilities.

• New Caledonian Crows: These crows fashion sticks into hook-shaped probes to extract food from hard-to-reach places.
• Japanese Crows: Some Japanese crows place nuts on roads for cars to crack open, then retrieve the edible contents.
• Aesop's Fable Replication: An experiment replicated Aesop's fable, showing crows dropping stones into a water-filled tube to raise the water level and reach a food reward.

Play and Development

Corvids engage in play activities, which are thought to contribute to their learning and development.

• Playful Behavior: Corvids have been observed sledding down roofs on plastic lids.
• Developmental Period: Corvids have a longer developmental period than other songbirds, and play is believed to foster learning and intelligent behavior.

Social Structure and Cooperation

Corvids exhibit complex social structures and cooperative behaviors.

• Cooperative Breeding: They breed cooperatively.
• Group Dynamics: They live and communicate in large, dynamic groups.
• Food Sharing: They share food.
• Mobbing Predators: They mob predators together.
• Lifelong Partnerships: Some corvids form lifelong partnerships, recognizing their companions and predicting their behaviors.

Challenging Previous Assumptions

Early scientific interpretations underestimated corvid intelligence.

• Ludwig Edinger's Misinterpretation: In the late 1800s, German scientist Ludwig Edinger compared primate and crow brains and incorrectly deemed the crow brain as primitive.
• Neuron Density: While a raven's brain is smaller and structurally different from a Capuchin monkey's brain, both animals have a similar number of neurons in their pallium, the brain region associated with cognition.

Conclusion

Corvids are highly intelligent animals with sophisticated cognitive abilities, including strategic food acquisition, social cognition, tool use, and problem-solving skills. Their intelligence is supported by a complex social structure and a brain with a high density of neurons in the pallium, despite its different evolutionary path compared to primate brains.