Question

Migratory birds fly to faraway areas during a particular time of the year. Which of the following conditions present in their habitat during that time are responsible for behavior?
(i)Unavailability of food
(ii)Extreme weather conditions
(iii)Overcrowding
(iv)Lack of nesting area
(a)ii and iii
(b)i and iii
(c)i and iv
(d)i and ii

Answer 1

Hint: Bird migration is a process of moving, due to adverse climatic conditions, to different habitats. Birds fail to collect food due to extreme weather conditions and they cannot lay their eggs.

Complete answer:
The physical, biological, and climatic conditions depending on the dwelling of a species in a specific area. The adverse conditions due to any climatic changes or food shortages cause the birds to migrate in search of better living conditions to nearby areas. Migratory species may contribute to a decrease in the biodiversity of the area in question.
To shift from areas of low or declining resources to areas of high or rising resources, birds migrate. Food and nesting areas are the two primary resources being sought. The birds move south again as winter arrives and the supply of insects and other food decreases.

Additional Information: Many different patterns of migration exist. The majority of birds migrate to southern wintering grounds from northern breeding areas. However, in southern parts of Africa, some birds breed and migrate to northern wintering grounds, or horizontally, in winter to enjoy milder coastal climates. During the winter months, other birds live on the lowlands and fly up a mountain for the summer.
To fly rapidly and over long distances, migratory birds have the ideal morphology and physiology. Their path is always an exhausting one, during which they meet their limitations. The Red Knot has one of the longest cumulative migration routes of any species, flying twice a year for up to 16,000 kilometers. In Siberia, it breeds and winters on the west coast of Africa, some of which also go down to the tip of South Africa.
So, the correct answer is ‘i and ii’.

Note: How migratory birds can fly with pin-point precision is truly incredible. It is not well known precisely how migrating birds locate their flyways. It has been shown that during the day, they can be oriented by the sun, by the stars at night, and by the geomagnetic field at any time. Some species can also sense polarised light, which can be used at night by many migrating birds for navigation.