sentence-transformers/squad huggingface dataset:
Passage: Migration is the regular seasonal movement, often north and south, undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat, or weather. Sometimes, journeys are not termed "true migration" because they are irregular (nomadism, invasions, irruptions) or in only one direction (dispersal, movement of young away from natal area). Migration is marked by its annual seasonality. Non-migratory birds are said to be resident or sedentary. Approximately 1800 of the world's 10,000 bird species are long-distance migrants.

Question: Why do birds migrate?

Question: What are non=migratory birds called?

Question: How many species of birds are there?

Question: How many bird species are long distance migrants?

Question: Which direction do birds primarily migrate?
Passage: Many bird populations migrate long distances along a flyway. The most common pattern involves flying north in the spring to breed in the temperate or Arctic summer and returning in the autumn to wintering grounds in warmer regions to the south. Of course, in the southern hemisphere the directions are reversed, but there is less land area in the far south to support long-distance migration.

Question: Along where do many birds migrate?

Question: What is the most common directionof migration in autumn?

Question: What is the most common pattern of migration in the spring?

Question: Why do the birds fly north?
Passage: The primary motivation for migration appears to be food; for example, some hummingbirds choose not to migrate if fed through the winter. Also, the longer days of the northern summer provide extended time for breeding birds to feed their young. This helps diurnal birds to produce larger clutches than related non-migratory species that remain in the tropics. As the days shorten in autumn, the birds return to warmer regions where the available food supply varies little with the season.

Question: What is the primary motivation for migration?

Question: Which birds will not migrate if they are well fed through winter?

Question: When do the birds return to warmer regions?

Question: what do the longer days of summer provide the birds?

Question: What do diurnal birds produce as opposed to non migratory species?
Passage: These advantages offset the high stress, physical exertion costs, and other risks of the migration. Predation can be heightened during migration: Eleonora's falcon Falco eleonorae, which breeds on Mediterranean islands, has a very late breeding season, coordinated with the autumn passage of southbound passerine migrants, which it feeds to its young. A similar strategy is adopted by the greater noctule bat, which preys on nocturnal passerine migrants. The higher concentrations of migrating birds at stopover sites make them prone to parasites and pathogens, which require a heightened immune response.

Question: What is hightened during migration?

Question: Where do Eleonora's falcon breed?

Question: What do Eleonora's falcon feed their young?

Question: What preys on nocturnal passerine migrants?

Question: What makes birds prone to parasites and pathogens?
Passage: 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.

Question: What is partial migration?

Question: Where is partial migration most common?

Question: In Australia, what percent of non-passerine birds are partially migratory?

Question: In Australia, what percent of passerine species are partially migratory?

Question: What is leap frog migration?
Passage: Within a population, it is common for different ages and/or sexes to have different patterns of timing and distance. Female chaffinches Fringilla coelebs in Eastern Fennoscandia migrate earlier in the autumn than males do.

Question: Which sex of the chaffinches Fringilla coelebs migrate earlier?

Question: Where are chaffinches Fringilla coelebs from?

Question: When do the chaffinches Fringilla coelebs migrate?
Passage: Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes termed flyways. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often different. A common pattern in North America is clockwise migration, where birds flying North tend to be further West, and flying South tend to shift Eastwards.

Question: How do most migrations begin?

Question: What to the migrating birds usually follow?

Question: What obsticals will migrating birds avoid?

Question: What is a common pattern in North America migration?

Question: What are the preferred routes for migration called?
Passage: Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 12–20% of the energy they would need to fly alone. Red knots Calidris canutus and dunlins Calidris alpina were found in radar studies to fly 5 km/h (3.1 mph) faster in flocks than when they were flying alone.

Question: How do most birds migrate?

Question: How much energy do geese conserve flying in a flock?

Question: How much faster do Red knots and dunlins fly in a flock?

Question: What does flying in flocks reduce?

Question: How do birds conserve energy?
Passage: Birds fly at varying altitudes during migration. An expedition to Mt. Everest found skeletons of northern pintail Anas acuta and black-tailed godwit Limosa limosa at 5,000 m (16,000 ft) on the Khumbu Glacier. Bar-headed geese Anser indicus have been recorded by GPS flying at up to 6,540 metres (21,460 ft) while crossing the Himalayas, at the same time engaging in the highest rates of climb to altitude for any bird. Anecdotal reports of them flying much higher have yet to be corroborated with any direct evidence. Seabirds fly low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds. However most bird migration is in the range of 150 to 600 m (490 to 1,970 ft). Bird strike aviation records from the United States show most collisions occur below 600 m (2,000 ft) and almost none above 1,800 m (5,900 ft).

Question: What part of birds was found on an expedition to Mt. Everest?

Question: Which birds have the highest rates of climb to altitude?

Question: What kind of birds fly low over water?

Question: What altitude range is most migration recorded?

Question: Where do most in air collisions occur?
Passage: 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.

Question: How do penguins migrate?

Question: How far do penguins travel when they migrate?

Question: How do Dusky grouse migrate?

Question: How do Emus migrate long distances during droughts?

Question: Where are Emus from?
Passage: 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.

Question: Where do the pink-footed goose migrate?

Question: Where do the dark-eyed junco migrate?

Question: Where do the European pied flycatcher breed?

Question: Where does the European pied flycatcher spend the winter?

Question: How do young learn migratory routes?
Passage: Often, the migration route of a long-distance migrator bird doesn't follow a straight line between breeding and wintering grounds. Rather, it could follow an hooked or arched line, with detours around geographical barriers. For most land-birds, such barriers could consist in seas, large water bodies or high mountain ranges, because of the lack of stopover or feeding sites, or the lack of thermal columns for broad-winged birds.

Question: What route does a migrating bird usually follow?

Question: What geographical barriers to land birds try to avoid?

Question: Why do migrating land birds avoid large water bodies or mountain ranges?

Question: Why do broad winged birds avoid geographical barriers?
Passage: The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, brent geese Branta bernicla migrating from the Taymyr Peninsula to the Wadden Sea travel via the White Sea coast and the Baltic Sea rather than directly across the Arctic Ocean and northern Scandinavia.

Question: What do water birds avoid while migrating?

Question: Where do brent geese migrate from?

Question: Where do brent geese migrate to?

Question: How do brent geese migrate?
Passage: A similar situation occurs with waders (called shorebirds in North America). Many species, such as dunlin Calidris alpina and western sandpiper Calidris mauri, undertake long movements from their Arctic breeding grounds to warmer locations in the same hemisphere, but others such as semipalmated sandpiper C. pusilla travel longer distances to the tropics in the Southern Hemisphere.

Question: What are waders called in North America?

Question: Where do dunlin Calidris alpina migrate to?

Question: Where do semiplamated sandpiper C. pusilla migrate to?

Question: Where do western sandpiper Calidris migrate from?
Passage: For some species of waders, migration success depends on the availability of certain key food resources at stopover points along the migration route. This gives the migrants an opportunity to refuel for the next leg of the voyage. Some examples of important stopover locations are the Bay of Fundy and Delaware Bay.

Question: What does successful migration depend on for some waders?

Question: Where do migrants refuel?

Question: Where is an important stopover location?

Question: What is another stopover location?
Passage: Some bar-tailed godwits Limosa lapponica have the longest known non-stop flight of any migrant, flying 11,000 km from Alaska to their New Zealand non-breeding areas. Prior to migration, 55 percent of their bodyweight is stored as fat to fuel this uninterrupted journey.

Question: Which bird has the longest migration?

Question: How far do bar-tailed godwits travel to migrate?

Question: Where do bar-tailed godwits migrate from

Question: Where do bar-tailed godwits migrate to?

Question: How much of the bar-tailed godwits bodyweight is stored as fat before migration?
Passage: Seabird migration is similar in pattern to those of the waders and waterfowl. Some, such as the black guillemot Cepphus grylle and some gulls, are quite sedentary; others, such as most terns and auks breeding in the temperate northern hemisphere, move varying distances south in the northern winter. The Arctic tern Sterna paradisaea has the longest-distance migration of any bird, and sees more daylight than any other, moving from its Arctic breeding grounds to the Antarctic non-breeding areas. One Arctic tern, ringed (banded) as a chick on the Farne Islands off the British east coast, reached Melbourne, Australia in just three months from fledging, a sea journey of over 22,000 km (14,000 mi). Many tubenosed birds breed in the southern hemisphere and migrate north in the southern winter.

Question: Which seabird has the longest-distance migration?

Question: Which bird sees more daylight than any other during migration?

Question: How long did one Arctic tern take to migrate?

Question: How far did the Arctic tern chick travel?

Question: Where do tubenosed birds breed?
Passage: The most pelagic species, mainly in the 'tubenose' order Procellariiformes, are great wanderers, and the albatrosses of the southern oceans may circle the globe as they ride the "roaring forties" outside the breeding season. The tubenoses spread widely over large areas of open ocean, but congregate when food becomes available. Many are also among the longest-distance migrants; sooty shearwaters Puffinus griseus nesting on the Falkland Islands migrate 14,000 km (8,700 mi) between the breeding colony and the North Atlantic Ocean off Norway. Some Manx shearwaters Puffinus puffinus do this same journey in reverse. As they are long-lived birds, they may cover enormous distances during their lives; one record-breaking Manx shearwater is calculated to have flown 8 million km (5 million miles) during its over-50 year lifespan.

Question: Which species are great wanderers?

Question: How far did a Manx shearwater fly over it's lifespan?

Question: Which bird broke a record in how far it flew over it's life?

Question: How long did the Manx shearwater live?

Question: How far will Puffinus griseus migrate each year?
Passage: Some large broad-winged birds rely on thermal columns of rising hot air to enable them to soar. These include many birds of prey such as vultures, eagles, and buzzards, but also storks. These birds migrate in the daytime. Migratory species in these groups have great difficulty crossing large bodies of water, since thermals only form over land, and these birds cannot maintain active flight for long distances. Mediterranean and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large raptors and storks pass through areas such as the Strait of Messina, Gibraltar, Falsterbo, and the Bosphorus at migration times. More common species, such as the European honey buzzard Pernis apivorus, can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants. This is a notable factor in the Central American migratory bottleneck. Batumi bottleneck in the Caucasus is one of the heaviest migratory funnels on earth. Avoiding flying over the Black Sea surface and across high mountains, hundreds of thousands of soaring birds funnel through an area around the city of Batumi, Georgia. Birds of prey such as honey buzzards which migrate using thermals lose only 10 to 20% of their weight during migration, which may explain why they forage less during migration than do smaller birds of prey with more active flight such as falcons, hawks and harriers.

Question: What do some large broad-winged birds rely on to help them soar?

Question: When do large birds of pray migrate?

Question: What is one of the heaviest migratory funnels?

Question: How much of their body weight do honey buzzards lose during migration?

Question: How many birds funnel through Batumi, Georgia each year?
Passage: 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.

Question: When do many insectivorous birds migrate?

Question: Which kinds of birds land for a few days before resuming migration?

Question: What are smaller insectivorous birds referred to?

Question: How long do passage migrants stop and feed before resuming migration?
Passage: Nocturnal migrants minimize predation, avoid overheating, and can feed during the day. One cost of nocturnal migration is the loss of sleep. Migrants may be able to alter their quality of sleep to compensate for the loss.

Question: What is a benefit of nocturnal migration?

Question: What is a cost of nocturnal migration?

Question: How do nocturnal migrants compensate for loss of sleep?

Question: What is another benefit of nocturnal migration?
Passage: 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.

Question: What are many long distance migrants genetically programmed to do?

Question: How do species that move short distances know when to migrate?

Question: Why do mountain and moorland breeders move only altitudinally?

Question: Where do the merlin Falco columbarius migrate to?

Question: How far do British chaffinch more in their lives?
Passage: Short-distance passerine migrants have two evolutionary origins. Those that have long-distance migrants in the same family, such as the common chiffchaff Phylloscopus collybita, are species of southern hemisphere origins that have progressively shortened their return migration to stay in the northern hemisphere.

Question: How many evolutionary origins do short distance passerine migrants have?

Question: Which species have long-distance migrants in the same family?

Question: Why have some specied progressively shortened their return migration?
Passage: Species that have no long-distance migratory relatives, such as the waxwings Bombycilla, are effectively moving in response to winter weather and the loss of their usual winter food, rather than enhanced breeding opportunities.

Question: What species has no long-distance migratory relatives?

Question: What are the waxwings Bombycilla moving in response to?

Question: Why are the waxwing Bombycilla not migrating for?
Passage: In the tropics there is little variation in the length of day throughout the year, and it is always warm enough for a food supply, but altitudinal migration occurs in some tropical birds. There is evidence that this enables the migrants to obtain more of their preferred foods such as fruits.

Question: Where is there little variation in the length of day throughout the year?

Question: Why does altitudinal migration occur in some tropical birds?

Question: What are tropical birds preferred foods?

Question: Where is it always warm enough for food supply?
Passage: Sometimes circumstances such as a good breeding season followed by a food source failure the following year lead to irruptions in which large numbers of a species move far beyond the normal range. Bohemian waxwings Bombycilla garrulus well show this unpredictable variation in annual numbers, with five major arrivals in Britain during the nineteenth century, but 18 between the years 1937 and 2000. Red crossbills Loxia curvirostra too are irruptive, with widespread invasions across England noted in 1251, 1593, 1757, and 1791.

Question: For what reason would birds mor far beyond the normal range?

Question: How many times did Bohemian waxwings come to Britain in the nineteeth century?

Question: How many times did Bohemian waxwings come to Britain between 1937 and 200?

Question: What years did Red crossbills invade England?
Passage: Bird migration is primarily, but not entirely, a Northern Hemisphere phenomenon. This is because land birds in high northern latitudes, where food becomes scarce in winter, leave for areas further south (including the Southern Hemisphere) to overwinter, and because the continental landmass is much larger in the Northern Hemisphere. In contrast, among (pelagic) seabirds, species of the Southern Hemisphere are more likely to migrate. This is because there is a large area of ocean in the Southern Hemisphere, and more islands suitable for seabirds to nest.

Question: In which hemisphere does bird migration primarily happen?

Question: Where do birds from high northern latitutes migrate to?

Question: Why do birds migrate south in winter?

Question: Which species of seabirds are more likely to migrate?

Question: Why are seabirds from the southern hemisphere more likely to migrate?
Passage: The control of migration, its timing and response are genetically controlled and appear to be a primitive trait that is present even in non-migratory species of birds. The ability to navigate and orient themselves during migration is a much more complex phenomenon that may include both endogenous programs as well as learning.

Question: What controls a birds migration?

Question: How do birds navigate and orient themselves during migration?

Question: What is a primitive trait present even in non migrating birds?

Question: What is a complex phenomenon in regards to migration?
Passage: The primary physiological cue for migration are the changes in the day length. These changes are also related to hormonal changes in the birds. In the period before migration, many birds display higher activity or Zugunruhe (German: migratory restlessness), first described by Johann Friedrich Naumann in 1795, as well as physiological changes such as increased fat deposition. The occurrence of Zugunruhe even in cage-raised birds with no environmental cues (e.g. shortening of day and falling temperature) has pointed to the role of circannual endogenous programs in controlling bird migrations. Caged birds display a preferential flight direction that corresponds with the migratory direction they would take in nature, changing their preferential direction at roughly the same time their wild conspecifics change course.

Question: What is the primary cue for migration?

Question: How do birds act in the period before migration?

Question: What does Zugunruhe mean in English?

Question: What do caged birds display that corresponds with migratory direction in nature?

Question: When do caged birds change their preferential direction?
Passage: In polygynous species with considerable sexual dimorphism, males tend to return earlier to the breeding sites than their females. This is termed protandry.

Question: What is it called when males return earlier to the breeding sites than females?

Question: What happens in polygynous species with sexual dimophism?

Question: Why do males in polygynous species return before the females?