Jay Eruption

It seems almost ironic that I spent the best part of a day recently trying to photograph Jays in Dalby Forest with no success. These are after all characteristically very shy woodland birds, often all you see is a white rump flash or distant view of a bird flitting between trees. The loud horse cry is usually a clear give away. The North Yorkshire forests sustain moderately good breeding populations, which anecdotally appear to be expanding. So it came as a pleasant surprise to find three birds on the coast "fresh in off the sea" at Filey today, totalling around 8 birds by the end of the day. Jays are not commonly encountered on the coast in the Filey/Flamborough region, an area in which breeding does not occur, due to a lack of suitable woodland habitat.

Jays are a largely sedentary member of the crow family which tend to winter in close proximity to where they breed, even juveniles tend not to disperse large distances. They feed heavily on acorns, which are an important food source during the autumn and winter. During September and October jays intensively collect acorns, which are then cached in ground. However oak is prone to irregular fluctuations in the acorn crop, especially with increasing latitude. When an acorn crop failure occurs this can cause the species to make mass eruptions, in which the usual breeding sites are left as the Jays search new areas to forage. Northern European populations are particularly prone to this eruptive behaviour, especially birds from Scandinavia and Russia.

Despite these eruptions, jays tend to avoid travelling across open water meaning these movements only occur when it is absolutely necessary. It is still unknown what age class predominate these eruptions (if any) or if they are also linked to productive breeding seasons. Certainly in 2012, already large numbers have been reported moving to Britain along the South-East/East coasts. I would expect more reports to come from this region of migrant jays over the remainder of the month.

Jays may be a frequent site along the coast this autumn

In addition to the jays, a single Lapland bunting, good numbers of blackbirds, three great spotted woodpeckers and a small number of song thrush were also recorded amongst the usual species. The bay was quiet with a small number of guillemots and a male eider present.