World Bird Migration Day (10th May, 2018)

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Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. It occurs mainly in the northern hemisphere, where birds are funneled on to specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.

The two primary resources being sought are;

  1. Availability of food
  2. Availability of nesting areas

Types of migration;

  1. Permanent do not migrate
  2. Short-distance migrants move only a short distance, as from higher to lower elevations on a mountainside.
  3. Medium-distance migrants cover distances that span from one to several states.
  4. Long-distance migrants typically move from breeding 

 Migration hazards include;

  1. including from hunting by humans
  2. vulnerability to predators
  3. and mortality
  4. tests birds physical and mental capabilities
  5. lack of adequate supply of food
  6. threat of collisions  from communication towers and building

Scientist use various techniques study birds migration such as;

  1. banding
  2. satellite tracking
  3. geolocators

Birds’ hotspots

Some places have been known to attract many birds due to

  1. good weather
  2. plentiful food
  3. attractive topography
  4. presence of garbage
  5. presence of water bodies
  6. presence of fish selling and farming  activates
  7. attractive nesting areas i.e. even airport walls and roofing
  8. game viewing lights

How birds navigate

Migrating birds can travel thousands of miles annually, taking the same route every year. Birds making their pioneering journey on their own would never go the wrong direction. Somehow they can find their winter home despite never having seen it before, and return the following spring to where they migrated from.

It is believed that they find their way through their magnificent combination several different types of senses when they navigate. They also get compass information from the sun, the stars, and by sensing the earth’s magnetic field, the position of the setting sun, from landmarks seen during the day and from sense of smell.

Some birds such as waterfowl and cranes follow certain pathways on their annual migrations. These pathways are often related to important stopover locations that provide food supplies critical to the birds’ survival. Smaller birds are known to migrate in broad fronts across the landscape. Recent studies using eBird data are revealing that many small birds take different routes in spring and fall, to take advantage of seasonal patterns in weather and food.

Bird Migration in Kenya

It is believed that 4-5, 000 million birds migrate to Africa alone each year to avoid winter. Some visit Kenya in August, but many arrive between September and December and fly back home in spring to enjoy the plentiful insect and attractive breeding grounds. Some birds cover a total of 20,000 kilometers return journey like song birds are attracted by game viewing lights. Some prefer traveling at night in order to avoid predators.

In Kenya it is said that 21% of birds are migratory that of these 171 Palaearctic, 55Afrotropical, 4 Malagasy, non migratory species are also mobile, 46% are water birds. 70% of these migratory birds are at the Rift Valley and the Coast. These birds are always enroute through Rift Valley, Coast, Eastern bush land, Central and Western grasslands.

Compiled by Grace C. Sitienei – of the University of Nairobi Library

Sources

  1. https://www.allaboutbirds.org/the-basics-how-why-and-where-of-bird-migration/
  2. https://martinasblogs.blogspot.co.ke/2014/05/kenya-and-migratory-birds.html#!/2014/05/kenya-and-migratory-birds.html
  3. http://www.birds.org.il/Data/Wings%20over%20Afrika/320_1995416465.PDF