1993 RCAHMS Aerial Survey

As all readers will no doubt remember, the summer of 1993 was the dullest, coolest and most unsettled of recent years. May produced the highest rainfall for that month yet recorded at Edinburgh, and, although this record was fortunately not equalled in the following months, the rainfall remained at or above normal, until, belatedly in August, it dipped below the monthly average. These wet conditions were unfavourable to the formation of cropmarks which require dry weather in late spring and summer in order to create the necessary crop stress. The surprising fact about this summer was that the season was as productive as it proved to be. In addition to the unfavourable conditions with regard to cropmark formation, the immediate cause of the all-prevading dullness was low cloud - so low that, for a large proportion of June and July, it prevented flying or at least the ability to see the ground, if a plane were in the air. Only 7 hours were flown in June and 18 in July, contrasting with the 25 and 60 of June and July 1992. when the weather, though hardly spectacular, permitted regular reconnaissance. August, however, did produce suitable conditions for 15 flights, totalling 39 hours in the air. flying later in the month than is normally productive, since, in general, the crops were harvested later than usual. A particularly regrettable consequence of the poor flying weather was the limited opportunity to survey the west and the north. The summer months yielded some 420 sites. The proportion of previously recorded material to new sites has been maintained at about 30%; there is a bias in favour of larger types of site. The season has produced its share of particularly interesting features, among which may be mentioned the extending of the series of pit-alignments adjacent to forts and settlements around the fringes of the Lammermuirs suggesting both an intensive and extensive system of land management. The identification of major new features in the ceremonial landscape at Balnaguard, not far from the confluence of the River Tay and the River Tummel. The identification of new forts and settlements was mainly confined to the eastern part of the country. The promontory fort at Castle Dykes on the south side of Dunglas Dean, Borders Region, not visible since its demolition earlier this century, was recorded along with a smaller, previously unknown, promontory fort.

Reconnaissance in the first half of the year also suffered from unfavourable weather conditions, with periods of high winds alternating with calmer intervals which were accompanied by extensive cloud or poor visibility and lasted for weeks at a time The aerial survey of the Mar Lodge Estate was completed in March, and further reconnaissance was carried out in the Commission's ground survey areas of Braes of Doune and Strathbraan where extensive areas of prehistoric and pre-improvement settlements were photographed, with a flight over Bute in support of the work of the local society.

RCAHMS (DES 1993, 117-8)