Don’t forget their clever New Caledonian ‘cousins’ (Corvus moneduloides)…using
tools, pulling strings, reasoning about causality…
Robin Hide
Hunt, G.R. and Gray, R.D. 2007. “Parallel tool industries in New Caledonian crows”. Biology Letters., 3(2), 173-5
Bluff, L.A., Troscianko, J., Weir, A.A.S., Kacelnik, A., and Rutz, C. 2010. “Tool use by wild New Caledonian crows
Corvus moneduloides at natural foraging sites.” Proceedings. Biological sciences Epub 2010 Jan 6., 277(1686), 1377-85.
Taylor, A.H., Elliffe, D.M., Hunt, G.R., Emery, N.J., Clayton, N.S., et al, . 2011. “New Caledonian Crows Learn the Functional Properties of Novel Tool Types”. PLoS ONE 6(12): , 6(12), e26887. doi:10.1371/journal.pone.002688.
Taylor, A.H., Medina, F.S., Holzhaider, J.C., Hearne, L.J., Hunt, G.R., and Gray, R.D. 2010. “An investigation into the cognition behind spontaneous string pulling in New Caledonian crows.” PLoS One, 5(2), e9345
Taylor, A.H., Miller, R., and Gray, R.D. 2012. “New Caledonian crows reason about hidden causal agents”. Proceedings of the National Academy of Sciences of the United States of America 109(40), 16389-91.
Abstract: The ability to make inferences about hidden causal mechanisms underpins scientific and religious thought. It also facilitates the understanding of social
interactions and the production of sophisticated tool-using behaviors. However, although animals can reason about the outcomes of accidental interventions, only
humans have been shown to make inferences about hidden causal mechanisms. Here, we show that tool-making New Caledonian crows react differently to an observable
event when it is caused by a hidden causal agent. Eight crows watched two series of events in which a stick moved. In the first set of events, the crows observed
a human enter a hide, a stick move, and the human then leave the hide. In the second, the stick moved without a human entering or exiting the hide. The crows
inspected the hide and abandoned probing with a tool for food more often after the second, unexplained series of events. This difference shows that the crows
can reason about a hidden causal agent. Comparative studies with the methodology outlined here could aid in elucidating the selective pressures that led to the
evolution of this cognitive ability.
From: John Harris [
Sent: Monday, 16 September 2013 3:00 PM
To:
Subject: [canberrabirds] Can crows count?
To all the crow enthusiasts,
My grandfather insisted that crows could count to 5.
There was a particularly wily old crow which perched all day in a tall gumtree near his lambing paddock, causing havoc with the newborn lambs. It knew what traps were, perched on them at first but after long investigation never entered
them.
It knew also what guns were and would not let anyone with a gun anywhere within range. Grandfather built a small hide in the lambing paddock and took his gun with him into it. The crow stayed at a distance. So Grandfather got my dad to
walk with him to the hide and then walk away leaving him there. The crow stayed at a distance, eying them but partly concealed on a high branch of the gumtree on the far side of the paddock.
Not to be outwitted, Grandfather got my uncle as well and the three of them walked to the hide and then two left, leaving Grandfather there with the gun. The crow remained concealed, just occasionally peeping around the branch of the tree.
So Grandfather sent Dad on his horse to get the next-door neighbour. He came and the the four of them walked to the hide. When the three departed the crow remained stubbornly in the tree. Dad wanted to get Grandma but Grandfather reckoned the crow could tell
a woman from a man. So the next-door neighbour got his labourer.
The five of them walked to the hide, squeezed in, waited a minute, and then the four of them left Grandfather there. Everybody waited a long time but at last the crow decided it was safe and flew down to the fence near the new-born lambs.
And there Grandfather shot it. He wore five of its tail feathers in his hat for the rest of his life.
So there you have it, crows can count to 5…or wait a minute, is that actually only 4…?
