Country diary: Birds of a feather in a noisy argument A noisy dispute among crows in a sycamore tree reveals the presence of a black crow, distinct from the common hooded crow found in Ireland. This observation leads to a discussion about the scientific classification of hooded and carrion crows, which can interbreed but are considered separate species. Genetic studies indicate a minimal genetic difference between them, yet visual cues in mate selection maintain population separation.

• A confrontation between crows in a sycamore tree revealed a black crow among the typical grey hooded crows.
• The hooded crow, with its grey body and black extremities, is common in Ireland and parts of Scotland.
• The all-black carrion crow is more common in the rest of Britain, with some presence on the east coast of Northern Ireland.
• Hooded and carrion crows can interbreed, but have been designated as separate species since 1758.
• Genetic studies show a very small genetic difference between the two species, but visual cues for mating keep their populations distinct.