The "Butterfly Effect" is the canonical illustration of sensitivity to initial conditions. The image of the butterfly is ascribed to Edward N. Lorenz. In 1963, he used a seagull as an example:
One meteorologist remarked that if the theory were correct, one flap of a seagull's wings would be enough to alter the course of the weather forever.
By 1972, the seagull was replaced; at a meeting of the American Association for the Advancement of Science, Lorenz spoke on "Predictability: Does the Flap of a Butterfly's Wings in Brazil set off a Tornado in Texas?" [Cited by Hilborn RC (1994). Chaos and nonlinear dynamics (Oxford University Press).]
Before the Butterfly Effect one encounters the obscurely known Grasshopper Effect:
The most general type of sweep is that which brings a system from a state of unstable equilibrium to a state of stable equilibrium. The changes of the atmosphere which constitute weather phenomena are the most familiar examples of the general type of sweep. A state of unstable equilibrium is produced by the heating of the lower strata of the atmosphere. An infinitesimal action, as the waving of a fan, may precipitate a sweep, and slight variations of the circumstances, time and place of the beginning of the sweep may produce modifications in the progress of the sweep which are absolutely incommensurate to these causes, or in other words, an infinitesimal cause may produce a finite effect.
Long range detailed weather prediction is therefore impossible, and the only detailed prediction which is possible is the inference of the ultimate trend and character of the storm from observations of its early stages ; and the accuracy of this prediction is subject to the condition that the flight of a grasshopper in Montana may turn a storm aside from Philadelphia to New York !
[Franklin WS (1898). Book review. Physical Review 6: 170-175.]