12 Jan 1989 - Day trip to Troia

On the other side of the Sado estuary is the holi­day town of Troia, connected to Setubal via a cheap car ferry service, so we take advantage as foot passengers. A few hundred metres from the jungle of tourist facilities we found a tidal inlet with lots of wader activity. The tide is out when we get there, exposing muddy sand covered with green algae. Dunlin, kentish, ringed and grey plovers and redshank, with cattle egrets and hundreds of gulls were all settled in.

The Kentish plover are charming to watch. They use the typical plover peck and run feeding action, but seem to crouch when running, and look about to overbalance.

The ringed plover are quite aggressive towards their smaller cousins, frequently chasing them. One jumps on top of a kentish, which calls and crouches before running off with the ringed plover in hot pursuit. Another nearby kentish crouches as if to hide, then resumes feed­ing as the ring plover leaves the area. Chases can be over just a couple of metres or much longer, in which case they are less intense. Yet sometimes both species are feeding close together without any obvious aggression.

A noise like falling pebbles ‑ a Kentish plover threat call ‑ called our attention to three birds in some other kind of dispute. A rather large male kentish (with feathers fluffed up to increase his apparent size) in breeding plumage repeatedly charges at a female/first winter bird trying to get too close. Another similar bird watches quietly from nearby. Eventually the second bird gets the message and goes off to feed.

The victorious male goes into a channel to bathe, yawning frequently ‑ a sign of nervous­ness. The third bird, presumably his mate, joins him and they alternate sessions of 15 ‑ 20 seconds of just lying belly deep in the water with bouts of normal bathing. The female leaves the water first and preens close by, often jumping into the air as she shakes herself. The male comes out a few min­utes later and preens briefly before they both resume feeding a metre or two apart.
Another pair of Kentish plovers land about ten metres away and start feeding. The two pairs seem to ignore each other for a few minutes, then taking up a hunched posture with his body parallel to the ground, head sunk into his shoul­ders and feathers of back and crown erect, the first male makes a long run straight toward the second male. Then we hear the rattling pebbles call again, and the first male stops, backs off and leaves second male alone. The second male has brighter, almost orange, head colouring, perhaps an indication of greater age or domination.

A redshank stands by a puddle screaming its head off ‑ a hissing scream repeated several times - then it resumes feeding quietly. The redshank, like the Kentish plovers, spend long periods just lying still in the water in between bouts of regular bathing. Perhaps the warmer water in this climate allows them to bathe more thoroughly.

Small flocks of gulls roost on sand bars in the inlet. They include a dozen each of adult and first winter Mediterranean gulls, individuals of which are liable to march over to a black‑­headed and peck hard just once to displace it, then settle down to roost again nearby.

A male clouded yellow butterfly pauses to feed on a roadside plant. This species hiber­nates successfully in southern Europe, and migrates northwards in spring to reach the rest of Europe by June.