Migration of birds and its causes.

3. Birds migration
Bird’s migration
Why Birds Migrate Differently
Frequency of Birds Migration
Top Ten Migratory Birds In The
World
Cause for migration
Types of Bird Migration:
Navigation in birds:
Adaptation for Migration
Birds migration routes in world
In Pakistan through Indus flyway
Studying Migration.
Threats to migratory birds
Disadvantages of Bird Migration
References

4. Bird’s migration
Latin word, migratus, which means “to
change
Examples
water fowl, hobara bustard, cranes, teals,
pintail, mallard, geese, spoon bills, waders,
pelicons and gadwall etc.

5. Why Birds Migrate Differently?

6. Frequency of Birds Migration
9,000 and 10,000 species of birds
Two thousand species of birds, make
regular seasonal movements.
40% of these migratory species are
declining
200 are now classified as globally
threatened (BirdLife, 2018).
enter into Pakistan from September-
November via Indus flyway

7. Top Ten Migratory Birds In The World (Dutta, 2017)
Bluethroat Alaska to Central Europe and Asia
. Insects, caterpillars and berries.
The Red Knot  from far north in the Arctic to the southern tip of
South America.
 travelling up to 16,000 kilometres twice a year
eat spiders and arthropods
Osprey  from North America, moves toward Central and
South America and Africa.
 dives up to three feet under the water to catch
fish
Greater
Flamingo
 Comes to India from Siberia during the winters.
 eat small crustaceans, molluscs, worms, insects,
small fish and sometimes some plant matter

8. Bar Headed
Geese
 Bar Headed Geese like to fly over Himalayan Mountains, to reach
Indian Subcontinent from Central Asia during winters
 Eat plants and crustaceans and invertebrates.
Cuckoo  migrates between Asia and Africa
 Some migrate to Southern Europe and Africa.
 cross the Mediterranean Sea and the Sahara in a single flight
Arctic Tern  Native to the Arctic and move toward Antarctic.
 Loves to eat insects, small fish, worms, mollusks, and crustaceans,
such as crayfish or shrimp.
The Great Snipe  travels to Africa during the winter season
 Eat Small invertebrates (worms and insect larvae).
Bar Tailed
Godwit
 Migrate to coasts in East Asia, Alaska, Australia, Africa,
northwestern Europe and New Zealand.
 Eat shellfish, marine snails and worms and shrimps.

9. Cause and for migration
• 1. Instinct and Gonadal changes:
• to migrate in birds is possibly instinctive (in born)
and the migration towards the breeding grounds is associated with gonadal
changes
• 2. Scarcity of food and day length
• shortening of day light
• scarcity
• Large hawks which feed on mammals and birds
• Fruit-eating birds may not have to migrate
• crossbill, finches
• Fish-eating birds arctic tern

10. 3. Photoperiodism:
1. The day length
affects pituitary and
pineal glands
2. Secret sex hormone
(geese) 4. Seasonal variation:
5. Climate:
Arctic breeding to
Antarctic
tropical regions to
temperate
6. Predators:
1, Birds that migrate
to different habitats can
avoid
2. steep coastal
cliffs or rocky offshore
islands.
7. Disease:
habitat is susceptible to
parasites

11. Types of Bird Migration
• Longitudinal migration:
• The longitudinal migration occurs when the birds migrate
from east to west and vice- versa (starling)
• Altitudinal migration
• The altitudinal migration occurs in mountainous regions
• Golden plover (Pluvialis) starts from Arctic tundra and goes
up to the plains of Argentina covering a distance of 11 250
km
• Move in flocks.

13. • Partial migration:
• Only several members of a group take part in
migration
• Blue Jays, Coots and spoon bills of our
country may be example of partial migration.
• Total migration:
• Vagrant or irregular migration:
• birds disperse to a short or long distance
for safety and food, it is called vagrant or irregular migration
(heron spoted egle)
• Daily migration:
• Seasonal migration:

14. Nocturnal and Diurnal Flight:
• Diurnal migration:
• . migrate during daytime for food. These birds are called diurnal
birds and generally migrate in flocks (hawks, crow, gees).
• Nocturnal birds:
• Some small-sized birds of passerine groups like
sparrows, warblers, etc. migrate in darkness, called
nocturnal birds.
• The darkness of the night gives them protection from
their enemies (Tinka).

15. Adaptation for Migration
• The hawk, with its large wingspan, is capable of speed and soaring.
• Gannets and seabirds are streamlined to dive at high speeds into the
ocean for fish
• .
• Some birds eat along the route, but some birds eat more just before
migration and store a special,
• Most birds that require food during the trip fly by night in small flocks.
This allows them to eat during the day, and avoid some predators.

16. Morphology
• increase the efficiency of long distance flight
• Wing pointedness is frequently
• migrants have smaller and flatter skulls than residents
Behavioural modification
• Behavioral traits of migratory birds, such as flock formation
• There is a 70% increase in efficiency when flying in V formation.
• benefits the communication among the birds.

17. Moult
• Feathers get worn by use and exposure to light
• insulatory function damaged
• plumage is replaced periodically
• redstarts
 stop for moult during migration


18. Navigation in birds:
Stellar Cues.
• Some Warblers (day
time)
• Some warblers (night
time)
• Sauer performed
experiments
Solar Cues
• need to see the sun to navigate
• Even nocturnal birds seem to take their
cue from the sun
• Kramer performed experiments
• Starlings (diurnal migrants)
• navigation and orientation of night
migrants is unknown.

19. Geomagnetic Cues.
• sea and desert often interrupt the migration routes
• songbirds, whose fat reserves
• magnetic cues might enable inexperienced migratory birds to
recognize
• Nightingales before their first migration simulating
migratory cues extend their fat-deposition period
• migration possess innate behavior
• celestial rotation appears to be dominant
• celestial cues appear to be controlled by the magnetic field

20. Birds migration routes in world
Africa-Eurasia
Flyway
 Europe and
northern Asia
with the Africa
 stop-over sites
in the Middle
East and
Mediterranean
East Asia-Australasia
Flywa
 north-east Asian with
the south-east Asia
and Australia,
 stop-over sites in
China
Americas Flyway
 North American
with the
Caribbean and
Central and South
America.

21. In Pakistan through Indus flyway
• In Pakistan, an estimated population of one million birds migrates
during winter.
• prefer to stay on various wetlands of Sindh province
• Quill migration in Pakistan
• There is a group of hunters that believe that the Quails migrate from
North to South reaching Sindh around mid-August

22. Migration of Houbara buster
• Migration patterns of Asian Houbara Chlamydotis
macqueenii wintering in the Cholistan Desert, Pakistan in 1998 were
monitored using satellite transmitters.
• arrived on breeding grounds in China, Mongolia and Uzbekistan
between 16 and 27 May
• stayed on their breeding areas for 135 days.
• arrived on the wintering grounds in the Cholistan Desert between 20
October and 15 December.

23. • 25,000-35,000 Houbara birds Pakistan CARs,
sinkian freezing temperature
• Covering about 5,500km distance from Siberia and CARs, the
• very quickly taking only five to seven days over a height of 4,730 meters to
Pakistan
• passing Chitral, Nowshera, Kohat, Lakki Marwat and stays in Dera Ismail
Khan, DG Khan and onward to Cholistan desert (Bahawalpur

24. Why it move to southern punjab?
• Houbara is very sensitive and it does not use the route again if they
sense any danger
• districts of D.I. Khan, Tank, Rahim Yar Khan, DG Khan and arid areas of
southern Punjab provide rich diversity of flora, fauna, insects and
weeds to the endangered species,
• Its population is declining in the range states of Afghanistan,
Pakistan, Iran, India, UAE and other Middle Eastern countries due to
illegal hunting and destruction of its habitats.

25. Studying Migration.
Banding
geolocators.
satellite
tracking,

26. Threats to migratory birds
Threats Intensity
High
Medium Low
Habitat destruction √
Hunting and fishing √
Poverty √
Unawareness √
Grazing √

27. Habitat destruction
• Hingol National Park from 2005-2007 and observed 204 species of
which 72 were winter visitors, 15 passage migrants, 16 summer
breeding visitors,
• Decline due to habitat destruction
Unawareness Fish hunting
Anthropogenic
activities