Summer Voyage to the Sea
A school trip in summer: the boat heads south, black birds fly above, yellow flowers bloom by the sea and a strong wind blows. A boy writes down memories — he doesn't want to forget.
~ながら means “while doing X, also do Y” — two actions at the same time.
Quote + と + 思う expresses an internal thought or opinion.
Negative desire (~たくない) + からです — “because I don't want to.”
An い-adjective in the ~くて form chains to the next clause.
な-adjectives attach to a noun via な.
~んだ / ~のだ + よ is an explanatory copula: “you see, …”. よ adds assertiveness.