Question: When do purple martins migrate to the continent where the yellow bell plant comes from?

full_context: Document 1: Bird migration: Bird migration is not limited to birds that can fly. Most species of penguin (Spheniscidae) migrate by swimming. These routes can cover over 1,000 km (620 mi). Dusky grouse Dendragapus obscurus perform altitudinal migration mostly by walking. Emus Dromaius novaehollandiae in Australia have been observed to undertake long-distance movements on foot during droughts.
Document 2: 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 3: Saint Barthélemy: Saint-Barthélemy has a marine nature reserve, known as the Reserve Naturelle that covers 1.200 ha, and is divided into 5 zones all around the island to form a network of protected areas. The Reserve includes the bays of Grand Cul de Sac, Colombier, Marigot, Petit Cul de Sac, Petite Anse as well as waters around offshore rocks such as Les Gross Islets, Pain de Sucre, Tortue and Forchue. The Reserve is designed to protect the islands coral reefs, seagrass and endangered marine species including sea turtles. The Reserve has two levels of protection, the yellow zones of protection where certain non-extractive activities, like snorkeling and boating, are allowed and the red zones of high protection where most activities including SCUBA are restricted in order to protect or recover marine life. Anchoring is prohibited in the Reserve and mooring buoys are in place in some of the protected bays like Colombier
Document 4: Bird migration: The Arctic tern holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year. Some species of tubenoses (Procellariiformes) such as albatrosses circle the earth, flying over the southern oceans, while others such as Manx shearwaters migrate 14,000 km (8,700 mi) between their northern breeding grounds and the southern ocean. Shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas.
Document 5: Saint Barthélemy: Marine mammals are many, such as the dolphins, porpoises and whales, which are seen here during the migration period from December till May. Turtles are a common sight along the coastline of the island. They are a protected species and in the endangered list. It is stated that it will take 15–50 years for this species to attain reproductive age. Though they live in the sea, the females come to the shore to lay eggs and are protected by private societies. Three species of turtles are particularly notable. These are: The leatherback sea turtles which have leather skin instead of a shell and are the largest of the type found here, some times measuring a much as 3 m (average is about 1.5 m) and weighing about 450 kg (jellyfish is their favourite diet); the hawksbill turtles, which have hawk-like beaks and found near reefs, generally about 90 cm in diameter and weigh about 60 kg and their diet consists of crabs and snails; and the green turtles, herbivores which have rounded heads, generally about 90 cm in diameter and live amidst tall sea grasses.
Document 6: 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 7: 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 8: Norfolk Island: Norfolk Island has 174 native plants; 51 of them are endemic. At least 18 of the endemic species are rare or threatened. The Norfolk Island palm (Rhopalostylis baueri) and the smooth tree-fern (Cyathea brownii), the tallest tree-fern in the world, are common in the Norfolk Island National Park but rare elsewhere on the island. Before European colonization, most of Norfolk Island was covered with subtropical rain forest, the canopy of which was made of Araucaria heterophylla (Norfolk Island pine) in exposed areas, and the palm Rhopalostylis baueri and tree ferns Cyathea brownii and C. australis in moister protected areas. The understory was thick with lianas and ferns covering the forest floor. Only one small tract (5 km2) of rainforest remains, which was declared as the Norfolk Island National Park in 1986.
Document 9: Saint Barthélemy: As the terrain is generally arid, the hills have mostly poor soil and support only cacti and succulent plants. During the rainy season the area turns green with vegetation and grass. The eastern part of the island is greener as it receives more rainfall. A 1994 survey has revealed several hundred indigenous species of plants including the naturalized varieties of flora; some growing in irrigated areas while the dry areas are dominated by the cacti variety. Sea grapes and palm trees are a common sight with mangroves and shrubs surviving in the saline coastal swamps. Coconut palm was brought to the island from the Pacific islands. Important plants noted on the island are:
Document 10: Saint Barthélemy: Agricultural production on the island is difficult given the dry and rocky terrain, but the early settlers managed to produce vegetables, cotton, pineapples, salt, bananas and also fishing. Sweet potato is also grown in patches. The islanders developed commerce through the port of Gustavia. Duty-free port attractions, retail trade, high-end tourism (mostly from North America) and its luxury hotels and villas have increased the island's prosperity, reflected in the high standard of living of its citizens.
Document 11: Saint Barthélemy: Other trees of note include the royal palm, sea grape trees in the form of shrubs on the beaches and as 5 to 7 m trees in the interior areas of the island, aloe or aloe vera (brought from the Mediterranean), the night blooming cereus, mamillaria nivosa, yellow prickly pear or barbary fig which was planted as barbed wire defences against invading British army in 1773, Mexican cactus, stapelia gigantea, golden trumpet or yellow bell which was originally from South America, bougainvillea and others.
Document 12: 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 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: Legends of the coco de mer: Nut and tree of the coco de mer, a rare species of palm tree native to the Seychelles archipelago in the Indian Ocean, is the subject of various legends and lore. Coco de mer is endemic to the Seychelles islands of Praslin and Curieuse. Before the Seychelles were discovered and settled, nuts of this species were sometimes carried by the ocean currents to distant shores, such as those of the Maldives, where the tree was unknown. These floating nuts did not germinate. The exceptional size and suggestive form of the nut, the circumstances of its discovery, and some unusual qualities of the trees have given rise to several legends.
Document 15: Bird migration: Many long-distance migrants appear to be genetically programmed to respond to changing day length. Species that move short distances, however, may not need such a timing mechanism, instead moving in response to local weather conditions. Thus mountain and moorland breeders, such as wallcreeper Tichodroma muraria and white-throated dipper Cinclus cinclus, may move only altitudinally to escape the cold higher ground. Other species such as merlin Falco columbarius and Eurasian skylark Alauda arvensis move further, to the coast or towards the south. Species like the chaffinch are much less migratory in Britain than those of continental Europe, mostly not moving more than 5 km in their lives.
ground_truth: winter
sub_queries: Where was the plant yellow bell brought from? Answer: South America
when do purple martins migrate to South America Answer: winter