The little bird wants to dance when it sees the rainbow.

Explanation:
Seeing a rainbow can be a magical experience for anyone, including a little bird. Rainbows are beautiful and colorful arcs that appear in the sky after rain showers. They are caused by the reflection, refraction, and dispersion of sunlight in water droplets, resulting in a spectrum of light appearing in the sky.

1. The bird's reaction:
When the little bird sees the rainbow, it gets filled with excitement and joy. It sees the vibrant colors stretching across the sky and is captivated by the beauty of the rainbow. The bird's natural instinct is to express its happiness and celebrate the moment.

2. Dancing as an expression of joy:
Dancing is often associated with happiness and celebration. It is a way for creatures, including birds, to express their emotions and enjoy themselves. When the little bird sees the rainbow, it wants to dance as a form of self-expression and to celebrate the beauty of the rainbow.

3. The bird's nature:
Birds are known for their playful and lively nature. They often engage in various activities like singing, flying, and hopping around. Dancing is another way for birds to express their energy and enthusiasm. The little bird, upon seeing the rainbow, feels the urge to move its body in a rhythmic and joyful way, showcasing its excitement.

4. Symbolic interpretation:
In a symbolic sense, the little bird wanting to dance when it sees the rainbow represents the essence of joy and celebration. The rainbow is a symbol of hope, beauty, and harmony. The bird's desire to dance signifies the positive emotions evoked by the rainbow and the ability to find joy in the simple pleasures of life.

In conclusion, the little bird wants to dance when it sees the rainbow because dancing is a natural and instinctive way for birds to express their joy and celebrate the beauty of their surroundings.