Migratory behavior of birds
Migration refers to periodic round trips between breeding and, non-breeding areas. Most migrations are annual, with nesting area in the northern region and winter grounds in south. Migrations occasionally involve east/west movements or altitude changes. Migration allows birds to avoid climate extremes and to secure adequate food, shelter and space throughout the year. Migration carries huge costs in predation including the hunting by humans and, is driven primarily by availability of food. It occurs mainly in the northern hemisphere where birds are funneled on to specific routes by natural barriers such as the Caribbean Sea. (Harrison, 1931)
Stimuli for migration
Birds migrate in response to species specific physiological …show more content…
The pituitary thus checks the development of gonads an in addition, affects all metabolic processes, including development of the thyroid gland. If only the pituitary and variations in day length were involved migration would be triggered at definite times.The pituitary cycle flexibility, would cause migrant populations to suffer arrival of spring, and biological phenomena such as hatching of insects and availability of food, are highly variable from year to year. The pituitary thus serves only to prepare the bird for flight. The availability of food is an important factor. Temperature and weather conditions also have an influence a sudden period of cold weather may induce the immediate migration of many migrants.(Hrrington,1991)
When birds migrate
Sedentary birds are usually sedentary during two periods each year at nesting time and winter.During almost all periods there are some latitudal movements of birds. Each group of organisms migrates at a specific time of the year. Other species are more irregular in their migaratory behavior. Red crossbills, for example are erratic wenderes and will settle down and breed any month of year where an adequate supply of conifer seed is available.(Hebrard, 1971)
Time of …show more content…
Molting: Fresh new feathers make flight easier, and most birds molt just prior to beginning their seasonal migrations. This molt is especially critical for dimorphic birds in summer, when their fall plumage will be more camouflaged and less noticeable to predators along their migration path. 2: Weight Gain: As the time for migration nears, many birds increase their production of fat-metabolizing proteins and their digestive tract begins to swells so they can gain weight more easily. Birds may seem to be overeating and can double their weight before leaving on migration, storing fat that will become fuel as they travel. The migratory bird’s gut is a really dynamic organ. In preparation for migration, the gut increases in size tremendously over several days.Its cells get larger and it produces new cells so the bird can increase its food intake and store up energy for the long flight." (Bennet, 1952)
2.Gonad Shrinkage: Birds' testes and ovaries will shrink almost as they prepare for migration in the fall, when those organs are no longer necessary for breeding. This decreases the weight of the internal organs so the birds can fly more easily without needing additional energy.
3.Hemoglobin
Migration refers to periodic round trips between breeding and, non-breeding areas. Most migrations are annual, with nesting area in the northern region and winter grounds in south. Migrations occasionally involve east/west movements or altitude changes. Migration allows birds to avoid climate extremes and to secure adequate food, shelter and space throughout the year. Migration carries huge costs in predation including the hunting by humans and, is driven primarily by availability of food. It occurs mainly in the northern hemisphere where birds are funneled on to specific routes by natural barriers such as the Caribbean Sea. (Harrison, 1931)
Stimuli for migration
Birds migrate in response to species specific physiological …show more content…
The pituitary thus checks the development of gonads an in addition, affects all metabolic processes, including development of the thyroid gland. If only the pituitary and variations in day length were involved migration would be triggered at definite times.The pituitary cycle flexibility, would cause migrant populations to suffer arrival of spring, and biological phenomena such as hatching of insects and availability of food, are highly variable from year to year. The pituitary thus serves only to prepare the bird for flight. The availability of food is an important factor. Temperature and weather conditions also have an influence a sudden period of cold weather may induce the immediate migration of many migrants.(Hrrington,1991)
When birds migrate
Sedentary birds are usually sedentary during two periods each year at nesting time and winter.During almost all periods there are some latitudal movements of birds. Each group of organisms migrates at a specific time of the year. Other species are more irregular in their migaratory behavior. Red crossbills, for example are erratic wenderes and will settle down and breed any month of year where an adequate supply of conifer seed is available.(Hebrard, 1971)
Time of …show more content…
Molting: Fresh new feathers make flight easier, and most birds molt just prior to beginning their seasonal migrations. This molt is especially critical for dimorphic birds in summer, when their fall plumage will be more camouflaged and less noticeable to predators along their migration path. 2: Weight Gain: As the time for migration nears, many birds increase their production of fat-metabolizing proteins and their digestive tract begins to swells so they can gain weight more easily. Birds may seem to be overeating and can double their weight before leaving on migration, storing fat that will become fuel as they travel. The migratory bird’s gut is a really dynamic organ. In preparation for migration, the gut increases in size tremendously over several days.Its cells get larger and it produces new cells so the bird can increase its food intake and store up energy for the long flight." (Bennet, 1952)
2.Gonad Shrinkage: Birds' testes and ovaries will shrink almost as they prepare for migration in the fall, when those organs are no longer necessary for breeding. This decreases the weight of the internal organs so the birds can fly more easily without needing additional energy.
3.Hemoglobin