Question

Why did the frog call the nightingale ''a brainless bird''?

Answer 1

The frog called the nightingale 'brainless' because she actually did not use her brain. If she had used her brain she would not have fallen victim to his deceitful exploitation. The brainless mistakes she committed were as follows:

1. She asked for the frog's opinion about her song in spite of receiving such a huge appreciation and applause from the creatures of Bingle Bog.
2. She expressed willingness to take training from the frog.
3. She did not flay away in spite of feeling unhappy and dissatisfied. 

Answer 2

Answer:

because of her lack of confidence she can't be able to sing properly in front of the audience