This common Black-hooded Gull is found throughout the Argentine country, down to Chupat in Patagonia, and is exceedingly abundant on the pampas of Buenos Ayres, where it is simply called _Gaviota_. In the month of October they congregate in their breeding-places--extensive inland marshes, partially overgrown with rushes. The nests are formed of weeds and rushes, placed just above the water and near together, several hundreds being sometimes found within an area of less than one quarter of an acre. The eggs are four in number, large for the bird, obtusely pointed, of a pale clay-colour, thickly spotted at the big end and sparsely on the other parts with black. Every morning, at break of day, the Gulls rise up from their nests and hover in a cloud over the marsh, producing so great a noise with their mingled cries that it can be heard distinctly at a distance of two miles. The eggs are considered a great delicacy, resembling those of the Plover in taste and appearance, and are consequently much sought after, so that when the locality near which a gullery is situated becomes inhabited the birds have no chance of rearing their young, as the boys in the neighbourhood ride into the marsh every morning to gather the eggs. The Gulls are, however, very tenacious of their old breeding-places, and continue even after years of persecution to resort to them. The young birds are of a pale grey colour, mottled with dull brown, and have a whining querulous cry. The plumage becomes lighter through the autumn and winter, but it is not until the ensuing summer, when the dark brown nuptial hood is assumed, that the young birds acquire the perfect plumage--soft grey-blue above, and the white bosom with its lovely pink blush.