They are aggressive and fearless birds, given their small size, at 19 cm (7.5 in), and will attack much larger species if their nest or young are threatened.

The common square-tailed drongo has short legs and sits very upright whilst perched prominently, like a shrike.

The square-tailed drongo was described by the Scottish zoologist Andrew Smith in 1834 from birds observed around Port Natal (now Durban) in South Africa.

[2] The specific epithet was chosen to honour the German botanist Baron von Ludwig who collected plants in South Africa between 1805 and 1847.

[4] Based on the results of a molecular phylogenetic study published in 2018, the taxonomy of the square-tailed drongo complex was reorganised.