Pigeon
The pigeon represents perhaps the most successful avian adaptation to anthropogenic environments in recorded history. These remarkable birds thrive in conditions that would fell lesser species—subsisting on discarded kebab meat, navigating labyrinthine underground railway systems, and nesting comfortably atop air conditioning units. Their magnetoreception abilities allow navigation across thousands of kilometres, whilst their crop milk production enables year-round breeding regardless of food availability. One might say the pigeon has evolved to exploit human civilisation with the efficiency of a well-designed parasite.
Elsa
Elsa's adaptability is, one must confess, rather more limited. Her powers function optimally in cold environments—a considerable handicap when one considers that 71% of Earth's surface consists of ocean and much of the remainder experiences temperatures above freezing. She did manage to construct an elaborate ice palace and a sentient snowman, demonstrating creative problem-solving under duress. However, her emotional regulation proved catastrophic, inadvertently cursing her own kingdom into perpetual winter. One struggles to imagine a pigeon making such an elementary governance error.
VERDICT
The pigeon's ability to thrive in any human settlement, from Mumbai to Moscow, decisively outperforms Elsa's geographically and emotionally constrained capabilities. Adaptability victory: Pigeon.