Festive mistletoe makes birds go all gooey

Festive mistletoe makes birds go all gooey

Mistletoe credit Zsuzsanna Bird

Countless sprigs of mistletoe are now hanging in homes across Britain, fleshy green candelabra under which seasonal kisses are shared, in a modern interpretation of an old Norse legend. However, these sprigs – with their symmetrical waxy leaves and surprisingly sticky, milky-white berries – have their own strange story.

Mistletoe is a partially parasitic plant of deciduous trees, mostly lime, apple, poplar and hawthorn, where it grows on suitable branches, often high above the ground. Its leaves provide energy through photosynthesis, but the plant also pushes its roots under the bark of its host tree to steal nutrients and water. 

Mistletoe grows from seed, using its berries to spread from one tree to the next. Birds, such as mistle thrush, redwing, fieldfare and blackcap, enjoy eating the berries, but then find their beaks coated in a messy, glutinous pulp of berry flesh and seeds, which they clean by vigorously wiping their beaks on tree bark.

The seeds have a special coating that acts like superglue, and as it hardens, each seed adheres firmly to its host tree. Birds will also regurgitate or excrete any undigested seeds, and these too will stick to branches.

The seeds stay firmly fixed during winter storms, and are ready to germinate in February and March. They grow their first roots, but it takes a full year before they are ready to produce leaves and start the slow process of growing into a recognisable mistletoe plant.

Mistletoe is uncommon in London, but it does have a few strongholds, including Bushy Park in Hampton, and Forty Hall Park in Enfield. It may become more widespread, as more and more blackcap are now migrating from Europe to overwinter in Britain, and they are just as fond of mistletoe at this time of year as we are! 

First published in the print edition of the Evening Standard Friday 22nd December 2017