A fleeting glimpse of a garish jay is a common sight on a autumn mushroom foray…
The jay is one of our most striking birds. Resplendent in its gaudy pink, blue, black and white plumage, you would think it would be obvious, but a fleeting glimpse is as much as we can normally expect. Generally its presence is only betrayed by a distinctive cackle from the dense foliage of the tree tops.
These elusive qualities seem to disappear in late autumn, however, when it suddenly becomes conspicuous. As the leaves fall, this colourful small crow becomes miraculously visible, flying purposefully from wood to copse and veteran oak to ancient neighbour with a characteristic bouncing flight. It is easy to link this with a particularly good breeding season, but in fact it is due to its winter survival strategy – and one which has great significance for foresters.
For most of the year the jay follows the omnivorous eating habits of the rest of its clan. Woodland insects, fruit, carrion, eggs and nestlings form the bulk of the diet, but as migrant songbirds depart and insect numbers dwindle, it switches its attention to acorns and beechmast. Every year each will stash literally thousands in caches across its territory. The bird gathers these frantically, cramming them into a specially adapted pouch in its gullet, before finally grabbing the final one into its beak. Then it is off to a secluded spot where it stabs a hole in the soil to push in one or two. Up to 3,000 may be stored in this fashion every month.
This is where the jay becomes of serious interest to the tree lover. Unlike downy birch seeds or winged ash keys which can be carried long distances by the wind, acorns and beechmast have no in-built means of moving from the immediate vicinity of their parent tree. Helped by a jay, however, they can be transported as much as half a mile before being carefully planted in soft soil.
The jay is no mug, of course. It has no interest in arboriculture. It is simply storing food as a guard against the long winter. Moreover, in one of the great feats of animal behaviour, it memorises the exact position of every cache. In some studies the birds have recovered literally every one of its thousands of secreted acorns. No memory is totally infallible, however, and usually at least a few escape detection. In other cases cold or predators claim the guardian before recovery. In the case of a December sparrowhawk strike, for example, this could leave thousands of buried acorns and beechmast spread over a square kilometre.
Naturally many of these germinate the next spring. This explains how oaks and beech can emerge in wasteland scrub and patches of ‘non-intervention’ forestry: making the jay an important conservation tool.
Their reliance on tree seeds (but acorns in particular) is also an interesting natural indicator of conditions further afield. Occasionally the failure of Continental oaks to fruit can lead to ‘irruptions’ of the normally solitary jay fleeing west in groups as they search for better foraging. During the autumn of 1993, for example, large influxes arrived in East Anglia with 90 counted heading west at Sherringham on just one day. But the biggest recent irruption was in 1983 when vast numbers moved from Poland and Scandinavia. This time the most impressive totals were recorded in the south-west with a flock of 1,000 reported near Land’s End and 3,000 counted near Plymouth.
Jays are also on the up. Because of their fondness for eggs and chicks, they used to be strictly controlled by gamekeepers – even though this was more a case of guilt by association. Certainly their cousins, crows and magpies, are serious threats to game bird nests. Jays generally prefer to forage high in the oak canopy for caterpillars, however, thus are much less of an issue.
As intensive gamekeeping has declined and attitudes become more enlightened, persecution has dropped (although they remain one of just 13 British birds which can be shot at any time). This has allowed a growth of numbers in their natural wooded habitat and even an expansion into suburbia where proximity to man seems to be whittling away at their natural timidity. Certainly their bright plumage and undoubted intelligence (they can learn to upend feeders to disgorge the peanuts) make them a popular visitor at many bird tables.
Their value to genuine tree- and nature lovers is much higher, however. Not only do they act as unpaid gardeners, unintentionally spreading some of our mightiest native trees, but they act as safari guides too. These are nature’s trackers, with keener eyes than any Kikuyu game warden. No sooner than their keen eyes spot an owl, fox, stoat or polecat than off goes the harsh alarm call (as reflected in its scientific name). Follow this quietly for a priceless sighting of some even more secretive resident – surely ample reward for the jay’s minor songbird indiscretions?