|Gull-billed Tern colony (Martin Kelsey)|
I find an abrupt counterpoint by water. Making my way beside the Alcollarín Reservoir, the sound reaches me from some distance. It is incessant, a cacophonous, rubbing almost nasal chitter. Gull-billed Terns with slow, deliberate flight head towards this sound, bearing small glistening fish fry from their jet black bills. Others, empty-billed, radiate away. On a small, low-lying island, tricoloured with its bands of sandy beach, vegetation green and blond dry stems in the centre, there is sound and motion. Over eighty pairs of Gull-billed Terns have opportunistically chosen this secure but transient site to establish a colony. Crowded mainly at one end, leaving the extreme eastern end of the slither of land for loafing Great Cormorants, the terns produce that wonderful sense of bickering and neighbourly squabbling. A bird arrives with a small fish, hovering briefly over its patch as it checks the best place to land for passing this gift to its mate. Most of the birds seem to be sitting tight on nests, but along the shoreline, there are two large tern chicks begging for food, confirming what I had suspected, that this breeding opportunity had been taken up by some pioneering pairs first with others coming on board later on. The Gull-billed Terns were not alone. Dwarfed and out-numbered, Little Terns with their darting jerky flight crossed the island and I reckoned that there were at least five nesting pairs there, away from the Gull-billed hullabaloo. The beach also was liberally dotted by incubating Great Crested Grebes, looking remarkably ungainly the land, their legs set almost as far back along their bodies as could be, gingerly waddling in a slow swaying motion from the water to the pile of weeds which served as the nest. Along the strandline Little Ringed Plovers were scampering, darting between the terns and grebes.
There were Black-headed Gills too and as a Black Kite flew over, sending the terns into an immedate panic, a pair of gulls set off after the kite to mob it. This display by the gulls to ward off such a threat I had not seen here before and it meant just one thing: that the gulls too had nests. On the side of the island in view, I saw two gulls that were sitting tight at the edge of the tall grasses. On the other side another bird was sitting, clearly incubating, whilst nearby there were a pair of adults with the dark brown downy forms of three small gull chicks. Abundant though this species is most of the year in Extremadura, it is a rare breeding bird, with just a small population spread across just a few breeding colonies. This finding represented a new breeding site for the species.