Question

Certain birds fly thousands of kilometres back and forth between regions every year - a phenomenon known as 'migration'. Which of these could lead birds to migrate back and forth between regions?

1. adverse weather conditions
2. unavailability of food
3. need for a good sense of geographical direction
4. pollution of lakes and other water reservoirs

Answer 1

Bird migration

Explanation:

• Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds.
• Birds generally migrate to move from areas of low or decreasing resources to areas of high or increasing resources.
• Thus, adverse weather conditions are the correct answer.

Answer 2

Every year birds migrate from their native regions for food and breeding to regions with a more favorable climate

• The migration of birds is a type of seasonal movement that occurs usually from the colder northern hemisphere to warmer regions in the southern hemisphere.
• This movement occurs mainly due to the lack of/ depletion of resources in the native regions from where the birds like pelicans, storks are originally from
• There are majorly two reasons why birds migrate, they are:

1. For nesting and breeding purposes
2. To obtain sufficient food

• Once the weather and food availability become suitable in their native lands, these birds migrate back as they are adapted to those conditions.

Thus, in the given question both (Option 1)  adverse weather conditions and (Option 2) unavailability of food is the cause for seasonal migration of birds.