|Stone Curlew (David Palmer)|
Once you have seen one, nearby shapes also metamorphose into Stone Curlews, some sitting on the ground, others like the first standing hunch-backed, a few taking a few paces walk. Ten birds..twelve...fifteen.. in view. But it takes a passing danger, perhaps a Marsh Harrier drifting overhead to get a true estimate of the numbers there. Seventy or eighty take flight, descending soon afterwards on a glide with their rather long gull-like wings.
I often wonder where they all come from. I know of two other roosts of similar size not more than a few kilometres away. Together the number of wintering Stone Curlew in these three roosts must exceed the breeding population within a similar radius. We do know that birds from northern Spain move further south in the winter and the Spanish population is supplemented by wintering birds from places like France and England. But until a bird turns up bearing a coloured-ring, I will only be able to guess the origin of them at this roost, although I can more safely assume that this communal roost will comprise the same birds from one year to the next, showing a site faithfulness or philopatry, which offers survival advantages drawn from familiarity with a particular area, its resources and risks.
On last Friday evening I was in Trujillo, undertaking parental duties waiting to collect our teenage son Patrick from a classmate's birthday party. As I sat in the car, I could hear the continuous sound of Spotless Starlings, still making a racket a couple of hours after nightfall from their communal roost site in a stand of trees in a town park. After a day feeding out on the plains, hundreds upon hundreds arrive at dusk. One theory about the function of such communal roosts is that they offer means for hungry starlings to obtain information about the best local food sources, presumably they follow well-fed birds out to the pastures the following morning hoping that they will be led to the right places. And I could only imagine the type of communication going on between these garrulous birds, well past their bed-time. In fact so much noise was coming from the roost that it took me a few minutes to register a different sound altogether. Trying to block out the starlings I could now recognise the unmistakeable sonorous deep hoot of an Eagle Owl. I walked along the street in the direction of the sound, looking upwards. And there, perched on top of a tower, seemingly oblivious to the sight and sound of traffic and people was the Eagle Owl, the street lamps catching, as it turned its face, its caramel-coloured eyes. I could even see the pale bases of the throat feathers each time it hooted. It sat there for half an hour, calling two or three times a minute, before silently gliding off on its broad wings to hunt. The nocturnal predator was on the move over the rooftops, as the diurnal starlings at last settled down in their roost.