The extinction of passengers pigeons was due to:

Options

A. Increased number of predatory humans
B. Over-exploitation by humans.
C. Non-availability of the food
D. Bird flu virus infection

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the cause of extinction of the Passenger Pigeon, a species known scientifically as Ectopistes migratorius.

2. **Identifying the Options**: We have four options to consider:
- A) Increased number of predatory humans
- B) Over-exploitation by humans
- C) Non-availability of food
- D) Bird flu virus infection

3. **Evaluating Each Option**:
- **Option A**: Increased number of predatory humans. This option suggests that humans were predators of the Passenger Pigeon. However, this is not the main reason for their extinction.
- **Option B**: Over-exploitation by humans. This option indicates that humans excessively hunted Passenger Pigeons, which is historically accurate. They were hunted for food and perceived as pests to agriculture.
- **Option C**: Non-availability of food. This option implies that the pigeons could not find food, which is not the primary reason for their extinction.
- **Option D**: Bird flu virus infection. This option suggests that a viral infection caused their extinction, which is incorrect.

4. **Conclusion**: After evaluating all options, the correct answer is **Option B: Over-exploitation by humans**. This was the primary reason for the extinction of Passenger Pigeons, as they were hunted extensively, leading to their population decline and eventual extinction.