The image of a chirpy robin perched on snow-capped spade handle has become such a festive season cliché that few people can imagine any other contender for the title of Christmas bird. Yet a lesser-known song bird has actually a far greater claim to the midwinter throne…
To glimpse the true king of the winter garden, first find a well-adorned holly tree or big bunch of mistletoe and then look for a dumpy brown sentinel perched above. If he proves difficult to spot, you should hear him bursting into song in the otherwise silent heart of winter. Indeed, as bad weather approaches, far from battening down the hatches he becomes noisier still – aware that cold and wet will only increase the lure of his precious food. This noisy display meant that to generations of countrymen he was known as the ‘storm cock’, but to modern bird lovers he is a mistle thrush.
The bird’s fierce behaviour is motivated not just by hunger, but by sex. When others are thinking purely of survival, the mistle thrush is planning for the breeding season ahead. Birds with the biggest food supplies emerge strongest from winter and end up with bigger clutches. They can also start breeding as early as March, allowing some to raise up to four clutches each season. Little wonder, therefore, that the owners of good fruiting territories drive off not only rival thrushes, but dive bomb redwings, fieldfares – and even wood pigeons and squirrels.
The link with the season is also reflected in the common and scientific (Turdus viscivorus) names. Both derive from mistletoe (Turdus means thrush; viscum – mistletoe and voro – to devour), but the associations with mid-winter run far deeper. When this is scarce, it readily adopts other Christmas plants such as yew or ivy: all pagan fertility symbols thanks to their lush foliage and heavy crops of berries when all else seems dead.
Mistletoe berries may keep our thrush population healthy through the winter, but it is by no means a one-way relationship. The birds help move this primitive parasite to new trees by wiping their beaks clean after dining on the sticky juice and seeds.
Although the noisy Christmas thrushes may already be thinking of sex and starting to establish breeding territories near their precious stash of berries, reproduction only begins in earnest as the supplies run out in February. By now it will have paird up and started to build an untidy nest, usually high in a tree, often adorned with scraps of litter, but always lined with mud and layered with soft grass. Here the hen lays four or five eggs which hatch a fortnight later. The chicks will fledge barely two weeks after this and a few days later the pair begins the cycle again. Two to three clutches a year are therefore normal – and even four is frequent.
They are true omnivores and rely on invertebrates to rear their hungry broods, proving their worth in the garden by devouring caterpillars, snails and slugs. The fondness for the last explains their recent decline, for they often fall victim to secondary poisoning when they eat slugs dying from pellets. When their last brood has fledged, however, their protein needs drop and they switch to hedgerow fruit.
The mistle thrush superficially resembles its more smaller relative, the song thrush, but is significantly larger and its breast is covered with larger, darker, spots rather than mottled brown streaks. More importantly, however, it seems much more confident because it stands very upright, forcing its chest out. It flies with the same bravado, taking on longer, higher, flights and where its wings undersides flash white rather than brown and as it flies it chatters with calls like tiny football rattles.