The migration of birds

The migration of birds

• Migration is the yearly, seasonal journey undertaken by many species of birds. During this journey, birds cover distances of many kilometres.

• The most common types of migration are those carried out by birds in the spring and the autumn. In the autumn, they travel from breeding grounds in the north to wintering grounds in the south, and vice versa in the spring.

Breeding grounds

Wintering grounds

Autumnmigration

Spring migration

Natural Science 2. Secondary Education

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• Large birds, like geese and birds of prey, usually migrate during the day.

Black geese flying in a V-formation

• But smaller birds, like robins, migrate at night.

Robin

The migration of birds

The migration of birds

Natural Science 2. Secondary Education

• Birds that migrate are called migratory birds, while birds that remain in one area are called sedentary birds or Resident birds.

Geese are migratory birds.

A sparrow is an example of a sedentary bird.

The migration of birds

The migration of birds

Natural Science 2. Secondary Education

Interesting examples

The white stork provides an example of how the amount of food available affects bird migration.

• These storks used to come to the Iberian Peninsula to spend the summer and breed. Then, in the autumn, they migrated to Africa to winter there. However, more and more storks now winter on the Peninsula.

• This is due to:

• A greater number of rubbish dumps that provide them with food throughout the year.

• It is likely that the change is also related to the higher temperatures resulting from climate change.

White stork

The migration of birds

Complete Migration

All individuals leave the breeding area

after raising their families

Most complete migrants breed in

temperate northern climates

Many complete migrants travel incredible

distances between breeding and

non-breeding habitats

Cerulean warbler Wilson’s plover Stilt sandpiper

Partial Migration

Seasonal movement by some, but not all,

individuals away from breeding area

Some overlap of breeding & non-

breeding ranges

Red-tailed hawk Herring gull Bewick’s wren

Latitudinal migration –American golden

plovers, Ruff

LONGITUDINAL MIGRATION

PATAGONIAN PLOVER

Altitudinal Migration-Wood-

cocks,Bushchat, grebe

The

Sahara

• Birds like swallows, bee-eaters, storks and birds of prey including black

kites, vultures and common kestrels journey from Africa to the Iberian

Peninsula to spend the summer.

Swallows

Black kite

UNIT

5The migration of birds

Climatic Migration-summer migrants

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Winter Migrants

• Migratory birds follow the same migration routes every year.

• Birds that migrate from Northern Europe to regions in the south of the

continent in the winter are called wintering or pre-Saharan birds (as they

do not cross the Sahara).

• Birds like geese and cranes come to the Iberian

Peninsula from Northern Europe to spend the

winter.

The

Sahara

Crane migration

Crane

UNIT

Natural Science 2. Secondary Education

Migrating-Wader birds

Arctictern

Interesting examples

• The Arctic tern travels the longest distance of any migratory bird: it journeys

from one pole to another two times a year, covering 40,000 km.

• Over the course of its life, about 26 years, an Arctic tern can travel up to 1

million kilometres.

Breeding grounds

Wintering grounds

Migratory routes

Natural Science 2. Secondary Education

Diurnal migrants Most birds which rely on gliding or flap

& glide flight are diurnal migrants

The chief benefit of daytime flight is thermals – rising currents of warm air that

provide lift

Ex-Cranes, swallows,bluejay etc

DAY OR NIGHT?

Nocturnal migrants

Many birds which use powered flightare nocturnal migrants.

Night flying helps birds avoid predators

Other benefits include calmer, more stable air

They rest & feed during day

DAY OR NIGHT?

MOON WATCHINGRequires a full moon, a comfortablechair and binoculars

How do

we study migration?

BANDINGUS Fish and Wildlife Service BirdBanding Laboratory

RADAR (NOAA)Several years ago, researchers at Cape May counted 14 million birds in one night

RADIO TELEMETRY

Carl Safina followed a single radio-

tagged albatross throughout its range

Why do birds migrate?

Migration is a strategy to take advantage of seasonally abundant food supplies

Weather and photo-period are triggers

SNOW BUNTING

DEC

JAN

FEB

MAR

APR

MAY

NOV

OCT

SEP

AUG

Anatomy of Flight

A fused sternum with a “keel” provides

the attachment points for the flight

muscles.

Route finding

Birds navigate by: visual landmarks, the sun, moon, stars, and routes learned from other birds

Birds also have an internal compass which issensitive to the Earth’s magnetic field

Migrating birds will maintain a true compass heading

MOON

LANDSCAPEFEATURES

SMELLS

WINDS

STARS

MAGNETICNORTH

SUNRISE

WEATHERUV LIGHT

SOUND

Fat is the currency of migration

Fat is the most important fuel for migration

Many species double their weight with fat fuel for migration

Shorebird Songbird Hawk

Typical Body Fat: PRE-MIGRATION

66% 70% 15%

Threats to migration

Loss of non-breeding ranges due to agricultureand seaside development

The destruction of the tropical and boreal forests

Habitat fragmentation

The biggest threat to migration is habitat loss