Jays on the move

There appears to be a definite shortage of acorns this autumn, something that is not just restricted to the county of Norfolk and which is already having an effect on some of our bird species. Most notable among these is the jay, one of our most resplendent birds and so beautifully described by Mark Cocker and Richard Mabey in Birds Britannica. With its “… electric blue patch on the pied wings and a body colour of warm greyish-pink, set off by bold moustaches, black crown freckles and a striking white rump” this is a stunning, though secretive bird. Such is the beauty of the blue wing feathers that jays were targeted by milliners, the feathers often gracing the hats of well-to-do ladies.

Over recent days I have seen or heard any number of jays, and many of these have been in open country which suggests that they are having to work hard to find the acorns that they favour. The acorn crop would normally form a key part of the diet for many months, with individual jays caching some 5,000 or so acorns in a normal year. The bird will collect three or four acorns in one go, transporting them to favoured locations to be stored in natural cavities or in damp ground. Amazingly, the jay is able to memorize the locations of most of the buried acorns, with those missed contributing to the regeneration and spread of oak woodland. A shortage of acorns in one area will prompt the jays to move elsewhere and this leads to periodic irruptions, with individuals from some northerly populations moving en masse into south-eastern Britain or the near Continent. Although one of the largest movements took place in the autumn of 1964, when 35,000 birds were counted moving over Gdansk in a four-week period, other significant irruptions have taken place more recently. For example, some 173 were noted passing Titchwell in October 1983 and smaller numbers have been noted arriving in off the North Sea since then.

A lack of other tree seeds, most notably beech mast and conifer seed, may well signal the arrival of greater than usual numbers of other bird species, including brambling, chaffinch and siskin. This is likely to lead to busier than usual bird tables and those monitoring garden bird populations are predicting a good winter for garden birdwatchers. No doubt, some of our rural gardens will be visited by jays, arriving early in the morning to feed on peanuts, bread and other scraps. Although not welcomed by everyone – jays are still controlled on many game estates – they are great fun to watch, full of character and brimming with a mischievous intelligence.