Lisa Burge’s photograph of a jay in flight prompted some research; we wondered how many jays our park could support.
Jays (Garrulus glandarius) are corvids, relative of the park’s crows, rooks, jackdaws and magpies. They are the UK’s most colourful corvid with bright blue flashes on their wings and a distinctive white rump that shows best in flight. They are shy woodland birds, rarely far from cover and difficult to see until they take flight; something they often announce with a loud shriek.
We have been increasing the park’s tree cover for some years now and it has become ideal territory for jays; lots of oaks in a mixture of woodland and meadow. Like magpies, jays are omnivores but they are best known for collecting and storing acorns for their winter diet. In the autumn they cache thousands of acorns which they carry away from the tree three or four at a time in a specially adapted gullet, and bury, sometimes individually, sometimes in batches. They seem to have a remarkable ability to remember where they put them.
We believe that we have at least one breeding pair of jays in the park. While Britain’s breeding population of jays is fairly sedentary, there seems to be a winter migratory population that depends on the acorn crop. Migrants are believed to come here from northern and eastern Europe when crops there have been poor.
Our acorn crop has been very poor this year; the long dry summer coupled with a knopper gall wasp population explosion was very damaging. Jays are territorial; if winter food is in short supply, they will chase away any competition for it. We don’t expect the park’s jays to increase in number this winter.