Tucking into the bog buffet

Flanders Moss NNR

On a visit to the lochan in the middle of Flanders yesterday some locals caught my eye. Above the surface of the water a spectacular flying display was going on. There was about 80 sand martins plus a few house martins zooming across the top of the lochan. Careering through this group like a BMW in rushhour were a small number of swifts – faster, bigger, dramatic and expecting everyone to get out of their way. It really was well worth watching, the birds twisting and turning, skimming the water, avoiding each other and every so often one would come close enough that you could hear the wiffle of its wings.

So what were they doing? Tucking into the insect buffet that is Flanders Moss. Flanders is a huge area of natural habitat surrounded by intensively managed bird food free farmland that is sprayed with insecticide and herbicide. It is like an insect factory, churning out millions of them, rare, common, flying, crawling, there are loads making Flanders their home. At the lochan yesterday there seemed to be a hatch of freshwater insects with lots of flying things over the water. The strong wind had helped to keep them in one place and the birds were taking advantage.

Birds living on the moss and the surrounding area were all tucking in. No swifts or house martins nest on the moss as they need buildings so they will have travelled from surrounding settlements just to feed on the moss. The sand martins might be more local and are probably from the sand pit that lies a 100 m west of the moss.

To give you an idea of how many insects are required, a sand martin can catch and eat about 60 insects an hour, 850 a day. But these birds are probably feeding young, a sand martin clutch might be between 4 and 7 chicks and they take a lot of feeding. Sand martin chicks take about 4 weeks from hatching from an egg to leaving the nest with a full set of feathers. So to feed a clutch of sand martins the parents might need to catch over 6000 insects a day. With a workload like that and hungry mouths to feed you can see why the insect buffet that Flanders provides is so important to birds across the Carse of Stirling.