Carrion Crows

The carrion crows around where I live seem to have had a successful year. Two young now fledged, who remain close to their parents. Regular visitors to the garden, they spend time observing the area before venturing down from wherever they have perched.

Carrion crows are members of the corvid (crow) family, of which there are eight UK-based species: carrion crow, hooded crow, magpie, raven, rook, jackdaw, chough, and jay.

The carrion crow is a highly intelligent, adaptable bird. They’ve had to be, as their territories have increasingly been taken over by human developments. They often mate for life, which can be up to twenty years. Although generally quite solitary in nature, groups of crows work together to raise a brood. This starts with nesting, where up to five adult males have been observed bringing materials to a female, who takes charge of construction. Once the clutch of eggs are laid (up to four), the female does most of the incubating, using her brood patch to keep the eggs warm.

When the young hatch, parents and helpers share the feeding. Helpers are often young, male offspring of the parent birds. Carrion crows have been known to remain with their parents for up to six years of age. Although having helpers means resources are shared between more adult birds than if just the two parents fed the young, it also means there is back up if either parent comes to harm.

Once fledged, the parents continue to feed the young for a few weeks after they leave the nest. Sometimes even for several months.

Quick Facts

Carrion crows are extremely intelligent birds. Their encephalization quotient (EQ – the ratio of brain size to body size) is 4.1. This is similar to that of a chimpanzee (4.2). By comparison, a human EQ is around 7.4, a domestic dog’s is 1.2, and domestic cats have an EQ in the region of 1.7. (The EQ measure was developed to provide indications of an animal’s ability to process information.)

People who leave food out for carrion crows have reported that the corvids have left gifts in return (‘gifting’). Studies have not found a definitive explanation for this behaviour. Some research suggests that the birds might be carrying something which they drop at a feeding point when they stop to collect food. With their levels of intelligence, it is not inconceivable that carrion crows learn that if they leave something at a bird table, they may receive more food in return. As with many animals, food is a great motivator for reinforcing behaviours.

Carrion crows have excellent memories, and remember faces. Studies have shown that carrion crows can remember faces for up to five years, and have been known to attack people who have caused them significant stress in the past. They also remember people who have been kind to them, showing greater trust towards these people. This information is relayed to social groups – both in terms of people to trust, and those who might cause stress.

Contrary to popular belief, carrion crows are not known to be attracted to shiny objects. Researchers think that this myth may have arisen because carrion crows kept as pets would pick up items which they perceived as being important to their people. Such items were likely to include jewellery, coins, and keys.

Further Information

Wildlife Trusts
RSPB
Woodland Trust
British Trust for Ornithology

Finally

A short plug for my new book, ‘Feline Friends‘. A celebration of cats, presented as a beautiful collection of stunning black and white, and full colour images.

“Cats have been in my family for many years. Firstly as members of the menagerie which surrounded me as a child. Then in adulthood as part of my own independent life. Are there more contrary creatures? They are independent and loving, docile and chaotic, graceful and clumsy. Much is written of cats in myth and legend; their connection to people transcends time and location. This book includes a couple of poems, and some general information about cats. But the focus is on the photographs, which will be appreciated by any ailurophile.”