Bird order on a branch – Five birds (Crow, Pigeon, Little Pigeon, Big Crow, Eagle) fly one after another. Big Crow flies after Crow but ahead of Eagle; Pigeon is between Crow and Big Crow. Which bird is last?

Introduction / Context:
We translate relational clues into a partial ordering, then extend it to determine the last position. Such problems hinge on recognizing that some elements must be to the right of all others due to constraints.

Given Data / Assumptions:

• Big Crow is after Crow, and ahead of Eagle.
• Pigeon is strictly between Crow and Big Crow.
• Little Pigeon has no positional constraint except being one of the five.

Concept / Approach:
From “Pigeon between Crow and Big Crow,” the triplet order is Crow < Pigeon < Big Crow. From “Big Crow ahead of Eagle,” we extend to Crow < Pigeon < Big Crow < Eagle. Little Pigeon can be anywhere relative to these, but cannot force anyone after Eagle.

Step-by-Step Solution:
Establish base chain: Crow < Pigeon < Big Crow.Append Eagle to the right: … < Big Crow < Eagle.Little Pigeon is free; placing it anywhere does not move Eagle leftward of Big Crow.

Verification / Alternative check:
Try placements of Little Pigeon at the extreme left, middle, or before Eagle; in all valid placements, Eagle remains to the right of Big Crow, hence is last.

Why Other Options Are Wrong:
Pigeon/Big Crow cannot be last due to the given chain; “None of these” and “Little Pigeon” conflict with the forced position of Eagle.

Common Pitfalls:
Reversing “ahead of” vs “after,” or ignoring the “between” constraint.

Final Answer:
Eagle