WALKING from the northern end of St David's station, I made my way via the rail crossing and the road bridge to the western bank of the River Exe.
It was a beautiful spring day, the flowers of blackthorn caught in the early morning sunshine.
The brilliant white of the blossom seemed to guide my eyes to the whites of violets, daisies and dead nettles among the grasses, a pair of mute swans swimming silently on the water and a magnificent little egret wading in the shallows.
Also conspicuous in this perfect light were the yellow-tinged catkins of a nearby willow, ready to discharge their pollen grains into the breeze.
Perched on a high branch, a chiffchaff sang loudly its "chiff chaff" song, prompting a response from another of its kind located further down river.
I continued northwards along the track which serves the flood barrier system. On reaching its end, I spotted a pair of lesser black-backed gulls, with their yellow bills and matching yellow legs, resting on top of the concrete wall which separates the river from the flood relief channel.
As they quietly surveyed their surrounds each with a wary eye kept on me, a pied wagtail searching for insects worked its "slow, slow, quick-quick-quick, slow" way along the wall. The wagtail looked so small when compared to the immovable brace of muscular giants that was stood in its path.
Taking avoiding action, it made a fluttering flight detour out from the wall and then back again to a point about a meter or two beyond the gulls. Wagtail continued to feed, gulls were unmoved.
I waited by the railings, hoping to see and to greet some old friends of mine. Had they made a safe return? How many had made it back?
Fortunately, I did not have to wait for too long. On hearing the familiar chattering, twittering, tell-tale song sounds of a sand martin flying in the blue sky overhead, I have to say I felt a great sense of both joy and relief.
This individual was joined quickly by a second and after a short while, by a third and a fourth. What a wonderful sight! Sand martins arcing above the flood barrier with their bodies tilted sideways and their wings outspread.
I attempted to follow the mesmeric flight path of one particular martin as it made another banking turn. With rapid wing beats it streaked across the air space directly in front of me before gliding and turning once again.
For a fraction of a second or two, it assumed an arrow-like posture, pulling its wings close to its body and then, in the next moment, its wings were held out again giving the martin some lift. As it glided downwards in between the walls which support the nearest of the two steel flood barrier gates, its song was amplified momentarily. Just beautiful! I am drawn to the flood barrier system throughout the spring and summer months in order to observe our Exeter sand martins. They have learned to take advantage of the steel barrier structures, constructing their simple nests within the hollow counterbalance beams. Each beam has several evenly spaced drainage holes in its lower surface. The martins use these as nest entrance holes.
The sand martin (Riparia riparia) is a species which nests in colonies. Usually established in sandy river banks or cliffs, these vary in size from several pairs to many hundreds.
The "flood barrier" colony is particularly small, numbering some 10 pairs each year and to the best of my knowledge, given the nature of the structures being used for nest sites, it is entirely unique.
Other man-made structures have been used by sand martins including quarries, gravel heaps and road cuts. Indeed, there is a history of Exeter birds using old drainage channels present in the walls of the mill streams. However, I have not come across a colony quite like this one.
Truly amazing! The four "flood barrier" birds had recently arrived back from their wintering quarters some 3,000 miles away in sub Saharan West Africa and it is probable they were all males.
Males return to their colonies before the females and using their beaks, feet and wings, they excavate metre-long burrows into the sandy bank or cliff.
The females are responsible for nest site completion. Of course, the flood barrier nest sites are prefabricated with no digging exertions required.
Perhaps not surprisingly, they have been chosen by the sand martins.
Safe, secure, shaded and with plenty of fast food insects emerging from the waters below, it is a sand martin des res par excellence.
