Concept:
World Migratory Bird Day is an international awareness campaign that highlights the need to conserve migratory birds and their habitats.
• Celebrated twice every year.
• Marks migration seasons in different hemispheres.
• Raises awareness about bird conservation.
Step 1: Understand why it is celebrated twice.
Migratory birds travel between:
Breeding and non-breeding grounds
in different seasons.
Step 2: Recall the 2026 observance dates.
World Migratory Bird Day in 2026 was observed on:
\[
9^{th}\text{ May and }10^{th}\text{ October}
\]
Step 3: Compare with options.
Among the options:
\[
9^{th}\text{ May and }10^{th}\text{ October}
\]
matches correctly.
Step 4: Final conclusion.
Hence, the correct answer is:
\[
\boxed{9^{th}\text{ May and }10^{th}\text{ October}}
\]