snipe, (kokuji)
鴫 centers on a specific bird: the snipe, a long-billed wading bird. It is a kokuji, a kanji created in Japan rather than borrowed from Chinese.
鴫 is a Japanese kokuji, combining 田 (rice field) with 鳥 (bird) to represent the snipe, a bird commonly found in wet fields.
A bird 鳥 in a rice field 田: that's a snipe, a wading bird often seen in muddy fields.
For しぎ, imagine a snipe in the field making a soft 'shigi' call as it probes the mud: shigi -> しぎ.
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