Question: When do purple martins migrate to the continent where the river Tebicuary River is a tributary of located?

full_context: Document 1: Bermejo River: The Bermejo River (Spanish, Río Bermejo) is a river in South America that flows from Bolivia to the Paraguay River in Argentina. The river is generally called Bermejo in spite of its different names along its way, but it also has its own Native American names; in Wichí it is called Teuco, and in Guaraní it is called Ypitá. In the plains of Argentina's Gran Chaco the Bermejo forms wetlands and splits into two branches. The southern branch is the bed of the old Bermejo River, now an intermittent stream called Río Bermejito. The northern branch is now the main stem of the Bermejo and is called the Teuco River ("Río Teuco"), Bermejo Nuevo, or simply the Bermejo River. The two branches rejoin at , near Villa Río Bermejito, forming the Lower Bermejo River.
Document 2: Quiquibey River: The Quiquibey River is a river in the Pilón Lajas Biosphere Reserve and Communal Lands in the north of Bolivia. The Quiquibey River joins the Beni River south of Rurrenabaque (upstream and south of Beni's tributary the Tuichi River). The river is the border between the departments of Beni and La Paz.
Document 3: Paraguay River: The Paraguay River (Río Paraguay in Spanish, Rio Paraguai in Portuguese, Ysyry Paraguái in Guarani) is a major river in south-central South America, running through Brazil, Bolivia, Paraguay and Argentina. It flows about from its headwaters in the Brazilian state of Mato Grosso to its confluence with the Paraná River north of Corrientes and Resistencia.
Document 4: Putumayo River: The Putumayo River or Içá River (, ) is one of the tributaries of the Amazon River, west of and parallel to the Japurá River.
Document 5: Bird migration: Many of the smaller insectivorous birds including the warblers, hummingbirds and flycatchers migrate large distances, usually at night. They land in the morning and may feed for a few days before resuming their migration. The birds are referred to as passage migrants in the regions where they occur for short durations between the origin and destination.
Document 6: Tebicuary River: The Tebicuary River (Spanish: Río Tebicuary), a tributary of Paraguay River is a river in Paraguay. Located in the southwestern part of that country, it flows eastwards discharging to Paraguay River about 45 km south of Formosa and 30 km north of Pilar.
Document 7: Bird migration: Within a species not all populations may be migratory; this is known as "partial migration". Partial migration is very common in the southern continents; in Australia, 44% of non-passerine birds and 32% of passerine species are partially migratory. In some species, the population at higher latitudes tends to be migratory and will often winter at lower latitude. The migrating birds bypass the latitudes where other populations may be sedentary, where suitable wintering habitats may already be occupied. This is an example of leap-frog migration. Many fully migratory species show leap-frog migration (birds that nest at higher latitudes spend the winter at lower latitudes), and many show the alternative, chain migration, where populations 'slide' more evenly north and south without reversing order.
Document 8: Tiputini River: The Tiputini River is a tributary of the Napo River in eastern Ecuador. It is the first major, navagable river south of the Napo and forms the northern border of Yasuni National Park. Unlike the Napo, the Tiputini has a relatively deep, narrow channel carved deep into the clay of the Amazon Basin, and it often fluctuates in depth by several meters from day to day.
Document 9: Paraguay: Paraguay (; ; , ), officially the Republic of Paraguay (; ), is a country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Although it is one of only two landlocked countries in South America (the other is Bolivia), the country has coasts, beaches and ports on the Paraguay and Paraná rivers that give exit to the Atlantic Ocean through the . Due to its central location in South America, it is sometimes referred to as "Corazón de Sudamérica" ("Heart of South America").
Document 10: Guaíra, Paraná: Guaíra is a municipality in the state of Paraná in the Southern Region of Brazil. The population is 32,591 (2015 est.) in an area of 560 km². The elevation is 517 m. This place name comes from the Tupi language and means "place difficult to access". The city is served by Guaíra Airport.
Document 11: Purple martin: The purple martin migrates to the Amazon basin in winter. Its winter range extends into Ecuador but does not seem to ascend far up the Andean foothills.
Document 12: São Lourenço River (Mato Grosso): The São Lourenço River is a tributary of the Paraguay River within the Pantanal, an alluvial plain that spans portions of Brazil, Bolivia and Paraguay.
Document 13: Purple martin: Wintering in South America, purple martins migrate to North America in spring to breed. Spring migration is somewhat staggered, with arrivals in southern areas such as Florida and Texas in January, but showing up in the northern United States in April and in Canada as late as May. Males usually arrive at a site before females.
Document 14: Bird migration: The typical image of migration is of northern landbirds, such as swallows (Hirundinidae) and birds of prey, making long flights to the tropics. However, many Holarctic wildfowl and finch (Fringillidae) species winter in the North Temperate Zone, in regions with milder winters than their summer breeding grounds. For example, the pink-footed goose Anser brachyrhynchus migrates from Iceland to Britain and neighbouring countries, whilst the dark-eyed junco Junco hyemalis migrates from subarctic and arctic climates to the contiguous United States and the American goldfinch from taiga to wintering grounds extending from the American South northwestward to Western Oregon. Migratory routes and wintering grounds are traditional and learned by young during their first migration with their parents. Some ducks, such as the garganey Anas querquedula, move completely or partially into the tropics. The European pied flycatcher Ficedula hypoleuca also follows this migratory trend, breeding in Asia and Europe and wintering in Africa.
Document 15: Río Turbio: Río Turbio is a town and municipality in the Güer Aike Department of the Santa Cruz Province in southern Argentina.
ground_truth: winter
sub_queries: What is Tebicuary River a tributary of? Answer: Paraguay River
Which continent is Paraguay River on? Answer: South America
when do purple martins migrate to South America Answer: winter