Seasonal Bird Populations

Humans have hunted birds for their meat and harvested their eggs since earliest times, and therefore humans have an interest in understanding the seasonal movements of bird populations. Birds are regarded as resident when they spend all year in the same area, and migratory if they move seasonally between the breeding and nonbreeding areas. Most birds of the tropics and some temperate species(species that live in areas with moderate temperatures) are resident, but many mid- latitude species, and most which breed in high latitudes, are migratory. The most common reason for an annual migration is to allow the bird to occupy a part of the world that provides food at only one time of year. In continental North America and Eurasia, insects are available only in summer in northern forested regions, so insect-eating birds migrate south in winter. Other reasons for migration include the weather, which becomes too cold or too wet at certain times of year, and competition from other species for food or nest sites. Nearly all migratory species are from the northern hemisphere, partly because seasons there are more distinct than in the southern hemisphere. Current migration patterns of northern hemisphere birds have evolved only in the past 10,000 to 5,000 years, since the end of the last Ice Age. They are thought to have been preceded in the Pleistocene (2,500,000 to 11,700 years ago)by shorter migrations because the temperate climatic zone at that time was more compressed geographically.

Many of the waterfowl today breed in the tundra of northern Eurasia, northern Canada and Alaska, Iceland, and Greenland, where the vegetation and insect life can support the birds during what is quite a brief breeding season. Geese, which breed up to the edge of the Arctic, migrate south in winter to escape frozen water; they remain in the northern hemisphere, but in milder regions. For example, the brant(brent goose)in North America migrates from Alaska and northern Canada to the Pacific and the Atlantic coast, and in Eurasia it migrates from Siberia to the coasts around western Europe. Many of the plovers follow a similar strategy, breeding inland and north, but returning to more southerly latitudes and to coastal locations in winter. Birds of these families are most easily caught on migration or in winter. Migration in seabirds takes a different form. Many come to land to breed but spend the rest of their life cycle at sea.

 

Even birds that do not migrate change their social behavior in winter. Many of the species that congregate and breed colonially (in large groups) become solitary in winter and occupy a single territory. Others congregate in flocks at that time. They also become more mobile, and both are adaptations to less predictable food supplies: a tree that may be full of berries one winter may have few or none the next. Hunters often target flocks rather than solitary birds, so hunting of those species that congregate is often a winter activity. Some species may be both migratory and sedentary. The woodcock, for instance, has a sedentary British population, which is enhanced in winter by migrants from Scandinavia.

From the point of view of humans who live in one place, certain birds are present in one season only, either in summer to breed or in winter; or they are passage migrants, appearing for a short time in spring and autumn during temporary stops to feed and rest while en route between summer and winter territories. Migratory birds can be a reliable seasonal source of food for people because they return each year at a predictable time but then leave, thus preventing numbers from being reduced too much by predation. In the main, migration routes are fairly fixed. For instance, many ducks follow the shoreline, and other species follow major rivers. Some avoid crossing wide expanses of water, so they concentrate at narrow crossing points such as Gibraltar at the entrance to the Mediterranean and Falsterbo at the mouth of the Baltic. Migrating birds store fat reserves under the skin, an adaptation to the journey to be taken, so many are at their most desirable from the point of view of human hunters as they start the migration.

1

Humans have hunted birds for their meat and harvested their eggs since earliest times, and therefore humans have an interest in understanding the seasonal movements of bird populations. Birds are regarded as resident when they spend all year in the same area, and migratory if they move seasonally between the breeding and nonbreeding areas. Most birds of the tropics and some temperate species(species that live in areas with moderate temperatures) are resident, but many mid- latitude species, and most which breed in high latitudes, are migratory. The most common reason for an annual migration is to allow the bird to occupy a part of the world that provides food at only one time of year. In continental North America and Eurasia, insects are available only in summer in northern forested regions, so insect-eating birds migrate south in winter. Other reasons for migration include the weather, which becomes too cold or too wet at certain times of year, and competition from other species for food or nest sites. Nearly all migratory species are from the northern hemisphere, partly because seasons there are more distinct than in the southern hemisphere. Current migration patterns of northern hemisphere birds have evolved only in the past 10,000 to 5,000 years, since the end of the last Ice Age. They are thought to have been preceded in the Pleistocene (2,500,000 to 11,700 years ago)by shorter migrations because the temperate climatic zone at that time was more compressed geographically.

The phrase “more compressed” in the passage is closest in meaning to

Amilder

Bmore varied

Ccooler

Dsmaller

 

2

Humans have hunted birds for their meat and harvested their eggs since earliest times, and therefore humans have an interest in understanding the seasonal movements of bird populations. Birds are regarded as resident when they spend all year in the same area, and migratory if they move seasonally between the breeding and nonbreeding areas. Most birds of the tropics and some temperate species(species that live in areas with moderate temperatures) are resident, but many mid- latitude species, and most which breed in high latitudes, are migratory. The most common reason for an annual migration is to allow the bird to occupy a part of the world that provides food at only one time of year. In continental North America and Eurasia, insects are available only in summer in northern forested regions, so insect-eating birds migrate south in winter. Other reasons for migration include the weather, which becomes too cold or too wet at certain times of year, and competition from other species for food or nest sites. Nearly all migratory species are from the northern hemisphere, partly because seasons there are more distinct than in the southern hemisphere. Current migration patterns of northern hemisphere birds have evolved only in the past 10,000 to 5,000 years, since the end of the last Ice Age. They are thought to have been preceded in the Pleistocene (2,500,000 to 11,700 years ago)by shorter migrations because the temperate climatic zone at that time was more compressed geographically.

In paragraph 1, all of the following are mentioned as reasons for bird migration EXCEPT

Athe limited availability of food during certain times of year

Bthe absence of sites suitable for breeding

Ctoo much competition for food from other birds

Dchanges in temperature or rainfall during some seasons

 

3

Humans have hunted birds for their meat and harvested their eggs since earliest times, and therefore humans have an interest in understanding the seasonal movements of bird populations. Birds are regarded as resident when they spend all year in the same area, and migratory if they move seasonally between the breeding and nonbreeding areas. Most birds of the tropics and some temperate species(species that live in areas with moderate temperatures) are resident, but many mid- latitude species, and most which breed in high latitudes, are migratory. The most common reason for an annual migration is to allow the bird to occupy a part of the world that provides food at only one time of year. In continental North America and Eurasia, insects are available only in summer in northern forested regions, so insect-eating birds migrate south in winter. Other reasons for migration include the weather, which becomes too cold or too wet at certain times of year, and competition from other species for food or nest sites. Nearly all migratory species are from the northern hemisphere, partly because seasons there are more distinct than in the southern hemisphere. Current migration patterns of northern hemisphere birds have evolved only in the past 10,000 to 5,000 years, since the end of the last Ice Age. They are thought to have been preceded in the Pleistocene (2,500,000 to 11,700 years ago)by shorter migrations because the temperate climatic zone at that time was more compressed geographically.

According to paragraph 1, resident birds differ from migratory birds in that resident birds

Aspend most of the year in breeding areas before moving briefly to nonbreeding areas

Blive primarily in the tropics and areas with moderate temperatures

Care better able to survive in cold and wet conditions

Doccupy parts of the world where there is little competition from other species

 

4

Many of the waterfowl today breed in the tundra of northern Eurasia, northern Canada and Alaska, Iceland, and Greenland, where the vegetation and insect life can support the birds during what is quite a brief breeding season. Geese, which breed up to the edge of the Arctic, migrate south in winter to escape frozen water; they remain in the northern hemisphere, but in milder regions. For example, the brant(brent goose)in North America migrates from Alaska and northern Canada to the Pacific and the Atlantic coast, and in Eurasia it migrates from Siberia to the coasts around western Europe. Many of the plovers follow a similar strategy, breeding inland and north, but returning to more southerly latitudes and to coastal locations in winter. Birds of these families are most easily caught on migration or in winter. Migration in seabirds takes a different form. Many come to land to breed but spend the rest of their life cycle at sea.

According to paragraph 2, when are plovers easiest for hunters to catch?

ADuring the breeding season

BDuring the later stages of their life cycle

CRight before they begin their migration

DDuring migration or when they have moved south or to the coast

 

5

Even birds that do not migrate change their social behavior in winter. Many of the species that congregate and breed colonially (in large groups) become solitary in winter and occupy a single territory. Others congregate in flocks at that time. They also become more mobile, and both are adaptations to less predictable food supplies: a tree that may be full of berries one winter may have few or none the next. Hunters often target flocks rather than solitary birds, so hunting of those species that congregate is often a winter activity. Some species may be both migratory and sedentary. The woodcock, for instance, has a sedentary British population, which is enhanced in winter by migrants from Scandinavia.

According to paragraph 3, all of the following are ways that different bird species adjust to winter EXCEPT

Aspending more time in flocks

Bcompeting with one another more intensely for territories

Cmoving from place to place more often

Dbreaking away from the group and spending more time alone

 

6

Even birds that do not migrate change their social behavior in winter. Many of the species that congregate and breed colonially (in large groups) become solitary in winter and occupy a single territory. Others congregate in flocks at that time. They also become more mobile, and both are adaptations to less predictable food supplies: a tree that may be full of berries one winter may have few or none the next. Hunters often target flocks rather than solitary birds, so hunting of those species that congregate is often a winter activity. Some species may be both migratory and sedentary. The woodcock, for instance, has a sedentary British population, which is enhanced in winter by migrants from Scandinavia.

Which of the following can be inferred from paragraph 3 about the British woodcock population?

AIt migrates in the winter.

BIt favors solitary breeding.

CIts numbers vary according to the season.

DIt is larger than the Scandinavian woodcock population throughout the year.

 

7

From the point of view of humans who live in one place, certain birds are present in one season only, either in summer to breed or in winter; or they are passage migrants, appearing for a short time in spring and autumn during temporary stops to feed and rest while en route between summer and winter territories. Migratory birds can be a reliable seasonal source of food for people because they return each year at a predictable time but then leave, thus preventing numbers from being reduced too much by predation. In the main, migration routes are fairly fixed. For instance, many ducks follow the shoreline, and other species follow major rivers. Some avoid crossing wide expanses of water, so they concentrate at narrow crossing points such as Gibraltar at the entrance to the Mediterranean and Falsterbo at the mouth of the Baltic. Migrating birds store fat reserves under the skin, an adaptation to the journey to be taken, so many are at their most desirable from the point of view of human hunters as they start the migration.

The word “desirable” in the passage is closest in meaning to

Aeasy to see

Beasy to catch

Cactive

Dappealing

 

8

From the point of view of humans who live in one place, certain birds are present in one season only, either in summer to breed or in winter; or they are passage migrants, appearing for a short time in spring and autumn during temporary stops to feed and rest while en route between summer and winter territories. Migratory birds can be a reliable seasonal source of food for people because they return each year at a predictable time but then leave, thus preventing numbers from being reduced too much by predation. In the main, migration routes are fairly fixed. For instance, many ducks follow the shoreline, and other species follow major rivers. Some avoid crossing wide expanses of water, so they concentrate at narrow crossing points such as Gibraltar at the entrance to the Mediterranean and Falsterbo at the mouth of the Baltic. Migrating birds store fat reserves under the skin, an adaptation to the journey to be taken, so many are at their most desirable from the point of view of human hunters as they start the migration.

In paragraph 4, why does the author mention the fact that ducks and other species follow coastlines and major rivers?

ATo support the idea that migration routes often remain the same over time

BTo give examples of bird species that require reliable sources of water during migration

CTo support the claim that coastline routes significantly reduce the time needed for migration

DTo provide evidence that ducks do not follow the migration patterns of most other bird species

 

9

Look at the four squaresthat indicate where the following sentence could be added to the passage

Whatever the route, these birds need lots of energy in order to travel long distances.

Where would the sentence best fit？Click on a square  sentence to the passage.

10

Bird migration patterns have been fairly consistent since the end of the last Ice Age.

ABirds in the southern hemisphere have similar migration patterns to those in the northern hemisphere, although southern hemisphere species breed in the south and fly north for winter.

BMost mid-latitude and high-latitude species are migratory, breeding in northern latitudes and moving south in the winter to warmer regions where insects and other food sources are more plentiful.

CSome previously sedentary birds, such as the woodcock of Britain and Scandinavia, have begun migrating to new areas in response to climate changes over the past several thousand years.

DResident birds that remain in the same location year-round need to adjust their behavior in the winter when food is more difficult to find.

EGeese are unique among migrating birds because they breed all the way up to the edge of the Arctic, where limited food sources prevent other birds from breeding.

FMigratory birds do not tend to change their migration routes and generally return to the same location, making them a predictable food source for hunters.

 

答案请付费后查阅：