_May 9_ (1883).--The effects of dawn over the vast desolations of the marisma were specially lovely this morning. Before sunrise the distant peaks of the Serranía de Ronda (seventy miles away) lay flooded in a blood-red light, and appearing quite twice their usual height. Half an hour later the mountains sank back in a golden glow, and long before noon had utterly vanished in quivering heat-haze and the atmospheric fantasies of infinite space. Amidst chaotic confusion of mirage effects we rode out across the wilderness: at first over dry mud-flats sparsely carpeted with dwarf scrub of marsh plants, or in places bare and naked, the sun-scorched surface cracked into rhomboids and parallelograms, and honeycombed with yawning cattle-tracks made long ago when the mud was moist and plastic; then through shallow marsh and stagnant waters gradually deepening. Here from a patch of rush hard by sprang three hinds with their fawns and splashed away through the shallows, their russet pelts gleaming in the early sunlight. Gradually the water deepened; "mucha agua, mucho fango!" groaned our companion, Felipe; but this morning we meant to reach the very heart of the marisma, and before ten o'clock were cooking our breakfast on a far-away islet whereon never British foot had trod before, and which was literally strewn with avocets' eggs, while nests of stilts, redshanks, pratincoles, and many more lay scattered around. [Illustration: STILTS DISTURBED AT THEIR NESTING-PLACE] During this day we discovered two nests of the slender-billed gull (_Larus gelastes_), not previously known to breed in Spain; also, we then believed, those of the Mediterranean black-headed gull (_L. melanocephalus_), though the latter were afterwards ascribed by oological experts (perhaps correctly) to the gull-billed tern (_Sterna anglica_), a species whose eggs we also found by the dozen.