Hoarders and feasters: how birds take advantage of natural food

First up are the hoarders. Jays are flamboyant members of the crow family, with jewel-like blue flashes on their wings. Far shyer than their all-black relatives, they are drawn into our gardens in autumn.

The Jay is an eye-catching visitor with a discordant call, and apt to send feeder regulars flying as it sweeps in. These are birds on a mission, determined to find acorns wherever they may be, scouting parks and gardens for as many as they can find.

From late September to early November, Jays collect acorns then hide them away to eat at a later date. Hiding places are many and varied, dug in the ground and buried under leaves, jammed between tree bark or hidden in holes in trees.

Smaller birds, too, will cache food to eat later. In the garden, keep an eye out for diminutive Coal Tits. Wary of bigger birds, they will steal away seeds from the feeders to eat at a more leisurely pace later.

Another hoarder is the Nuthatch. These pretty tree dwellers hide food for winter, wedging acorns, hazelnuts and seeds into bark fissures for safekeeping. Unlike Jays, who hide their acorns far and wide, Nuthatches keep them within a smaller area. Highly protective of these stored supplies, they will feistily defend their patch, remaining territorial over autumn and winter.

A Jay forages for acorns, storing them in its crop to cache later. Video: RSPB (rspb-images.com).

A second strategy is to feast on the autumn harvest. The first berries start fruiting from late August – blackberries and Rowan berries are two early examples. By October, this swells to a banquet with Hawthorn, Blackthorn and more all bearing fruit, soon to be followed by Ivy and Mistletoe. These berries are packed with energy that helps birds through the winter.

Birds will eat the easier to digest, ‘short shelf-life’ berries such as blackberries first. Those that stay fresher longer, or with a mild toxicity such as Ivy, are left until there’s less choice. Whether conscious or not, this is a clever strategy, ensuring the berry supply lasts as long as possible into the winter.

The sudden abundance naturally brings in a variety of birds. It’s not hard to see how the brightly coloured red, orange and yellow berries act like neon advertising hoardings, alerting birds to the harvest as they fly overhead.

It’s thought that black berries, such as Juniper and Ivy, may have an ultraviolet reflectance that is visible to some birds, although not to us.

But, of course, berry bushes aren’t here solely to feed birds. The berries contain the seeds for the next generation and the birds are a means of effective dispersal.

While most seeds are scattered after passing through a bird’s gut, one plant relies on its berries’ sheer stickiness. Mistletoe is a parasitic plant that grows in the branches of trees. Its sticky seeds fix to the bills of the birds and are ‘planted’ when the birds wipe their bills clean on a branch.

It’s not just our resident birds that reap the harvest, with a wave of migration seeing newcomers fly in from colder countries in northern Europe. Here come the hordes of hungry birds on the hunt for food. Fieldfares and Redwings are our ‘winter thrushes’, which flock to the UK from Scandinavia in autumn and feast on berries during their stay.

Another bird that may come for the berries in winter is the punky-looking Waxwing. These beautiful birds turn up only when the berries in their northern homelands of Russia and Scandinavia run dry. In such a ‘Waxwing winter’ we can enjoy sporadic flocks popping up, gorging themselves until the berries run out.

A Fieldfare feasts on berries and fruit. Video: RSPB (rspb-images.com)

Autumn also sees the arrival of large numbers of familiar species, including Blackbirds, Song Thrushes, Chaffinches and Robins. These are birds that breed in northern and colder parts of Europe but fly here for our relatively milder winter, joining our resident populations.

Birds know no borders and are motivated by the need to find adequate food and shelter wherever it may be. The number of these so-called partial migrants varies year-on-year depending on the weather. So come the colder months, it may well be that ‘your’ regular garden Robin is not a long-term resident but a visitor from overseas.