lesser spotted woodpecker
A small woodpecker species (Dendrocopos minor). The name is usually written in katakana, as is common for many bird names in Japanese.
The lesser spotted woodpecker is widely distributed across Europe and Asia.
アカゲラ (great spotted woodpecker) is a larger, more common woodpecker species. コアカゲラ is the smaller 'lesser' counterpart.
Katakana spelling is common for bird names and matches usual-kana usage.
Kanji spelling is rare and mainly encountered in older or specialized texts; the bird is normally written in kana.
From 小 (ko, 'small') + アカゲラ (akagera, 'great spotted woodpecker'). The name distinguishes it as the smaller species.