As last year drew near to its close, I was surprised to see two wood pigeons – fairly large birds – making a very gentle, slow approach to a holly bush in my garden.
With skills any rescue helicopter pilot would be proud of, they made a near-vertical descent to its stems … they are not really substantial enough to be called branches … alighting on them in what one would have thought was slow-motion had one been watching a piece of film. The graceful way in which these heavy birds coped with the significant bending of the shoots as the pigeons’ weight was transferred from their wings to their legs and their acrobatic skill as they clung on to the slender, free-flexing stems came as a complete surprise to me, who is used to the noisy, wing-flapping, rapid exit these birds usually make when I surprise them in my garden. And, of course, my curiosity was aroused by their in-my-experience unexpected behaviour.
The pigeons were … as you, gentle reader, may already have guessed … in quest of the berries with which the bush was adorned as Christmas approached. I have no idea at all why I was surprised to see pigeons eating holly berries, for I know that these bright red, winter-gracing drupes … fleshy fruits with thin skins and central stones containing the seed, like plums, cherries, almonds, or olives … feature in the diet of a fair number of birds. But I was surprised; and my surprise metamorphosed into curiosity about these haws.
Holly berries, I learn, can range in colour from the most common red through brown to near black; and green and yellow versions are not unknown. Each fruit contains up to ten seeds; and it is by the spreading of these seeds by birds after the flesh of the fruit has satisfied the birds’ hunger that wild holly bushes are spread. Indeed, along the west coast of North America, from British Columbia in the north to California in the south, the spread of holly seed from woodlands … where the shrubs are grown commercially … into the neighbouring native woods is something of a problem. As so often happens, an exotic plant introduced into an area by mankind with the best of intentions has had unintended consequences.
And when I learn that holly berries contain a number of toxins … poisons of plant or animal origin … that are harmful to humans, I am not surprised that holly berries can induce nausea, vomiting, diahorrea and intestinal problems if they are eaten by people. The most important of these toxins is saponin, which is used in soaps and detergents; and other toxins in holly berries include phenolic, a compound used in plastics and high pressure laminates, and alkaloids, which are commonly used in anaesthetics. Birds are seemingly immune to these toxins, as are some grazing animals: but I hope you didn’t encourage the family pets to treat themselves to holly berries during the festive season, and I trust that you made sure that the children understood not to eat these tempting little fruits.
I have referred, in the past, to that wonderfully comprehensive tome A Modern Herbal by Margaret Grieve, first published in 1931. And it is in its informative pages that I read that the berries are “violently emetic and purgative, a very few occasioning excessive vomiting soon after they are swallowed, though thrushes and blackbirds eat them with impunity. They have been employed in dropsy; also, in powder, as an astringent to check bleeding. … Roasted English Holly fruit was once used as a coffee substitute, but only when exercising extreme precaution.” And the very best precaution against mishaps with holly berries is: DON’T EAT THEM!