Chapter 10

Question 1

Migration vs Dispersal

Answer 1

• migration: Predictable back-and-forth movements; Repeated seasonally
• dispersal: Usually a unidirectional movement

Question 2

Name the different types of dispersal

Answer 2

• natal dispersal
• breeding dispersal
• postbreeding dispersal

Question 3

Natal dispersal

Answer 3

• movement between the site where an individual is born and the site where it first breeds

Question 4

Breeding dispersal

Answer 4

• movement between one breeding site and another

Question 5

Postbreeding dispersal

Answer 5

• typically refers to the wandering movements that some birds (e.g., herons) make after they finish breeding, but before they settle at a wintering site

Question 6

Why are temperate-zone and arctic latitudes a problem? What are the three responses to this?

Answer 6

• Abundant resources in the summer; Limited resources and harsh climatic conditions in the winter
• 3 responses:
  Migration - move to more favorable areas

Residency - with adaptations for tolerating harsh conditions

Hibernation - only documented for Common Poorwill

Question 7

Understand the differences in annual adult survival, and annual reproductive success in tropical resident

Answer 7

annual adult survival: Do not face hazards of migration, harsh winter
HIGH (80-90%)

annual reproductive success: No seasonally abundant food source for offspring (LOW)

Question 8

Understand the differences in annual adult survival, and annual reproductive success in migrant

Answer 8

annual adult survivial:Escape harsh winter but some die during migration
MODERATE (50%)

annual reproductive success: Seasonally abundant food source, but divert time, energy from breeding to migration
MODERATE

Question 9

Understand the differences in annual adult survival, and annual reproductive success in temperate resident

Answer 9

annual adult survival: Endure harsh winter and restricted food supply
LOW (20-50%)

annual reproductive success: Seasonally abundant food source
HIGH

Question 10

Philopatry

Answer 10

• Most individuals return annually to the same areas where they bred the year before

Question 11

understand the different patterns of migration

Answer 11

seasonal variation

 Residence
 Facultative Migration
 Partial Migrants
 Obligate Migration
 Nomadism

Question 12

Residence

Answer 12

• nonannual movement at all
• common in tropics
• examples: chowchilla, wreathed hornbill, ivory-billed woodcreeper

Question 13

Facultative migration

Answer 13

• migrate only under certain conditions
• example: northern lapwing, american robin, european blackbird

Question 14

Partial migrants

Answer 14

• some individuals within a population
• example: In different locations, European Blackbirds (Turdus merula) are year‐round residents, facultative migrants, or obligate migrants. Even within the region where blackbirds are present year round (green), the population includes full‐time residents, facultative migrants seeking refuge and resources because conditions farther north became unsuitable, and obligate migrants that migrate south every winter regardless of conditions in the north

Question 15

Oblique Migration

Answer 15

• Undertake predictable annual migrations to distant non‐breeding grounds
• Most songbirds that breed in the northern parts of North America, Europe, and Asia fall into this category

Question 16

Nomadism

Answer 16

• Move less predictably from one breeding ground to the next
• example: snowy owl

Question 17

Artic tern bird

Answer 17

• Every year, arctic terns migrate from the Arctic Circle to the Antarctic Circle—a round-trip journey of about 30,000 kilometers (18,641 miles)

Question 18

Flyway

Answer 18

• migratory route
• Established routes used year after year by large numbers of migrants
  Many bird species often converging to use similar flyways
• Not all birds use clearly defined flyways during migration (broad-front migration)

Question 19

Concentration Points

Answer 19

• Migrating raptors concentrate in narrow overland corridors
• Migratory concentrations also occur in areas where food is especially abundant, and many species of migratory birds spend substantial time at staging areas to refuel before continuing their migrations

examples: bar-tailed Godwit, cross thousands of miles of open ocean with NO stops

Question 20

Blackpoll Warbler migration

Answer 20

• fly directly from northeastern North America to the Greater Antilles and northern South America, often with a several day refueling stop
• They return to their northern breeding grounds more leisurely up the Atlantic Coast

Question 21

Wood thrushes

Answer 21

• tracked from Pennsylvania to winter territories in Costa Rica vary their return routes the next spring

Question 22

Austral migration

Answer 22

• South American flycatchers and swallows, among others, migrate seasonally from temperate-zone South America to the tropics of Brazil
• Relatively fewer birds in the southern hemisphere live in locations with extreme seasonal variations in temperature

Question 23

What time of day do raptors and passerines typically fly during migration?

Answer 23

• Hawks migrate during daylight hours when they can take advantage of warm rising air currents
• Swifts and swallows, which feed on the wing, also migrate by day
• Many small land birds, including most flycatchers, thrushes, and wood warblers, as well as rails and woodcocks, depart shortly after sunset and migrate by night
• Predation by hawks and gulls is less likely at night, and these migrants can then refuel by day

Question 24

At what altitudes do most migratory birds fly?

Answer 24

Most migrants fly at fairly low altitudes, usually below 700 to 800 meters
- example: Bar-headed goose

• Note: More stable night atmospheres with weaker horizontal winds and less turbulent vertical motion create favorable flight conditions; Cooler and more humid night air also favors heat loss and water retention

Question 25

What are fallouts?

Answer 25

- encountering strong headwinds

Question 26

Migration paces

Answer 26

"hop" >> short flights, rest and refuel "skip" >> longer flights, shorter refueling stops "jump" >> one long flight, no stops

Question 27

Example of migration pace

Answer 27

- Hudsonian Godwit - Stops at just one site in central USA on its northward flight from Patagonia to central Alaska, and at three sites on its way back to Patagonia in the northern fall 

Question 28

Loop migration

Answer 28

- Choose different paths in different seasons – wind conditions

Question 29

Leapfrog Migration

Answer 29

- Occurs in species with a broad breeding range - Individuals breeding the farthest north or south migrate to the most distant wintering areas, traveling farther and passing over birds that breed in intermediate areas - May evolve when conditions in the north become increasingly favorable and the edge of a species’ breeding distribution moves further and further north - example: Fox Sparrow

Question 30

Altitudinal Migration

Answer 30

- Changing elevation to exploit new resources under different environmental conditions example: Resplendent Quetzal

Question 31

Example of the idea that different ages and sexes may migrate to different places during the winter

Answer 31

- Dark-eye Junco - Adult females migrate farthest to the southernmost states; young males stay farthest north in Indiana and Ohio; adult males and young females settle at intermediate latitudes

Question 32

Migratory Divides

Answer 32

- Distinct breeding populations of the same bird species meet, yet birds from each side of the divide have different migration pathways - Birds from the southern population migrate to tropical West Africa; Birds from the northern population migrate to East and South Africa  - example: Willow Warbler

Question 33

Irruption

Answer 33

- Occasionally move in large numbers beyond their usual range, usually in response to poor food supplies in their typical habitats - examples; Great Gray Owl, Pine Grosbeak, Red-breasted Nuthatch

Question 34

Migratory Connectivity

Answer 34

- The degree to which a population of birds breeding in a distinct region remains cohesive as individuals move to a distinct region in the winter  - high connectivity is one breeding and one wintering ground travel location, while low connectivity has birds traveling to mutliple locations for breeding and wintering

Question 35

Example of migratory connectivity

Answer 35

- Migratory connectivity of breeding and wintering grounds of Black-throated Blue Warblers. Shaded colors map specific sets of isotopes in feather samples. Warblers that nest in the northern part of the species range tend to winter in the Caribbean west of warblers that nest in the Appalachian Mountains.

Question 36

Why is fat used to fuel migration?

Answer 36

- Fat yields twice as much energy and water per gram metabolized, as does either carbohydrate or protein - Migrants fatten rapidly just before migration by consuming enormous quantities of energy-rich food

Question 37

Why are stopover sites important for some migratory species?

Answer 37

- accumulate more energy - physiological recovery - avoiding adverse environmental conditions - spatiotemporal adjustments

Question 38

Zugunruhe

Answer 38

- migratory restlessness - Migrants, when kept in cages at night, usually jump in the direction that you would expect them to fly if they really were initiating their migratory journeys 

Question 39

Hyperphagia

Answer 39

- migratory fattening