Flamingos are regularly visible from El Calafate congregating in the waters of Lago Argentino. A group of birds congregating for rest is called a communal roost. Males form reproductive aggregations, congregating and collectively give off a pheromone that attracts reproductive females. This allows waiting passengers to be dispersed along the platform rather than congregating. The department advises travellers against congregating in areas popular with Western tourists. In this incident, security agents had opened fire on protesters congregating outside the Alay Hotel. Artillery fire discouraged the Sioux from congregating in large numbers. To prevent any black conspiring, the Democrats forbade blacks from congregating anywhere. White residents began congregating at and near the Tulsa County Courthouse. This was to cut down on congregating outside of liquor stores. Large numbers are often seen congregating on houses seeking an entry point. On August 21, Katipuneros were already congregating in Balintawak in Caloocan.