Bird Migration | 10 reasons you should care..
Migration of Bird
The word “migration” has come from the Latin word migrate which means going from one place to another. Many birds have the inherent quality to move from one place to another to obtain the advantages of favorable conditions. Bird Migration may be described as “changes of habitat periodically recurring and alternating in direction, This law proposed by L. Thomson (1926). which leads to secure optimal environmental conditions at all times”.
Types of Bird Migration:
All birds do not migrate but all species of birds are subject to periodical movements of varying extent. The birds which live in the northern part of the hemisphere have the greatest migratory power.
Bird Migration may be:
- (i) Latitudinal,
- (ii) Longitudinal,
- (iii) Altitudinal or Vertical,
- (iv) Partial,
- (v) Total,
- (vi) Vagrant
- (xii) Irregular,
- (viii) Seasonal,
- (ix) Diurnal and
- (x) Nocturnal
(i) Latitudinal migration:
In bird migration, latitudinal migration means movement from north to south and vice versa.
Most birds live in the land masses of northern temperate and sub-arctic areas, where they obtain nesting and feeding facilities during the summer. They move south during winter.
(ii) Longitudinal migration:
Longitudinal migration occurs when birds migrate from east to west and vice versa. Starlings (Sturnus vulgaris), a resident of western Asia and eastern Europe, migrate to the Atlantic coast. California gulls, resident and bred in Utah, migrate west to winter on the Pacific coast.
(iii) Altitudinal migration:
Altitudinal migration occurs in mountainous regions. Many birds that inhabit the mountain peaks migrate to the lowlands during winter. The golden plover (Pluvialis) begins in the arctic tundra and rises to the plains of Argentina, covering a distance of 11,250 km.
(iv) Partial migration:
All members of a group of birds do not participate in migration. Only several members of the group participate in the migration.
Blue Jays from Canada and the northern part of the United States travel south to mix with the sedentary populations of the southern states of the United States. Coots and spoons (Platalea) from our country can be an example of partial migration.
(v) Total migration:
When all members of a species participate in migration, it is called total migration.
(vi) Vagrant or irregular migration:
When some birds scatter a short or long distance for safety and food, it is called irregular or irregular migration. The example of vagrant or irregular migration may be Herons.
Other examples are the black stork (Ciconia nigra), the brilliant ibis (Plegadis falcinellus), the spotted eagle (Aquila clanga) and the bee-eater (Merops apiaster).
(vii) Daily migration:
Some birds make a daily journey from their nests due to the influence of environmental factors such as temperature, light and humidity as well. Examples are crows, herons and starlings.
(viii) Seasonal migration:
Some birds migrate at different seasons or times of the year to feed or reproduce, which is called seasonal migration, for example, cuckoos, swifts, swallows, etc. During the summer, they migrate from the south to the north during the summer.
These birds are called summer visitors. Again, there are some birds like snow, red wing, lark, gray plover, etc. that migrate from north to south during winter. They are called winter visitors
(ix) Daytime migration:
Many birds like crows, robins, swallows, hawks, jays, bluebirds, pelicans, cranes, geese, etc. they migrate during the day to feed or others.
These birds are called daytime birds and generally migrate in flocks.
(x) Night birds:
Some small birds of passerine groups such as sparrows, warblers, etc. migrate in the dark, called night birds. At night, darkness protects them from their enemies.
Causes of bird migration:
Most birds migrate more or less on time and follow routes regularly. The actual factors determining the course and direction of migration are not clearly understood.
The following factors may be related to migration issues:
me. Instinct and gonadal changes:
i. Instinct and Gonadal changes:
It is widely accepted that movement to migrate in birds is probably instinctive and that migration to breeding sites is associated with gonadal changes.
ii. Food shortage and day length:
Other factors for bird migration are believed to be food shortages, shortening of daylight and increasing cold to stimulate migration.
Bird migration depends on two main factors: stimulation and orientation.
Food shortages and falling daylight are believed to produce endocrine changes that initiate bird migration.
iii. Photo period:
Increasing the length of the day (photojournalism) induces bird migration. The length of the day affects the pituitary and pineal glands and also caused the growth of gonads that secrete sex hormones that are the stimulus for migration.
In India, Siberian crane, geese, (i) day migration:
Many birds like crows, robins, swallows, hawks, jays, blue birds, pelicans, cranes, geese, etc.
they migrate during the day in search of food or others. These birds are called daytime birds and generally migrate in flocks. Some small birds of passerine groups such as sparrows, warblers, etc. they migrate in the dark, called night birds. At night, darkness protects them from their enemies.
iv. Seasonal variation:
The migrations of birds from north to south take place under the stimulus of the internal condition of the gonads that are affected by seasonal variation.
The experiments of Rowan with Juncos (summer visitor to Canada) have established that light plays an important role in the development of gonads, which has an indirect role in migration. If the gonads undergo regression, the urge for migration is not felt. So the seasonal changes in illumination appear to be a crucial factor for determining migration.
Guiding Mechanisms in Bird Navigation:
For more than a century, the celestial navigation of birds has fascinated ornithologists.
Different explanations have been presented to explain how birds navigate.
It is difficult to generalize about the means of orientation and navigation in migration.
Different groups of birds with different modes of existence have developed different means of finding their way from one place to another (Pettingill, 1970).
Disadvantages of Bird Migration:
i. Many young people are not able to reach their destination because they die during the course of the continuous and tiresome journey.
ii. Sudden changes in the climate such as storms and hurricanes, a strong current of wind, fog are the causes for the death of a sizeable number of migrants.
iii. Sometimes man-made high tours and lighthouse cause the death of migratory birds. This is an another disadventure of bird migration.
iv. Man themselves are responsible for the death of the migrants. They shoot at these poor birds just for their own leisure and amusement.
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Bird migration FAQ
Which types of birds migrate?
Nomadically include waxwings, phainopeplas, zebra finches, and black swans are the Types of birds that migrate
What is migration?
Bird Migration may be described as “changes of habitat periodically recurring and alternating in direction
What is the longest bird migration?
The Arctic Tern Sterna Paradisaea has the longest migration of any bird, and sees more daylight than any other, moving from its arctic breeding grounds to Antarctic non-breeding areas.