Square-tailed Drongo

The square-tailed drongo (Dicrurus ludwigii) is a small, glossy black drongo of eastern and southern Africa. It measures about 18–19 cm; adult females weigh around 31 g and males about 36 g. Both sexes have deep red eyes, although males are often slightly glossier.

It resembles the larger fork-tailed drongo (Dicrurus adsimilis) but has a shorter tail with only a shallow notch, which can appear almost square when the feathers are aligned. Habitat is also useful for identification: square-tailed drongos favour forest and dense woodland, while fork-tailed drongos are more characteristic of open savanna and woodland.

The square-tailed drongo was formerly treated as part of a wider species complex extending far across sub-Saharan Africa. A taxonomic revision published in 2018 found clear genetic and morphological differences within the complex and helped clarify the limits of Dicrurus ludwigii, Sharpe’s drongo (Dicrurus sharpei) and the western populations then described as Dicrurus occidentalis. Under the current AviList treatment, the western form is included within Sharpe’s drongo as Dicrurus sharpei occidentalis, leaving the square-tailed drongo as an eastern and southern African species.

The species is closely associated with wooded habitats, including evergreen and riverine forest, dense woodland, forest edge and plantations where native undergrowth remains. It is generally much more dependent on dense vegetation than the fork-tailed drongo (Dicrurus adsimilis), although it can use forest edges and other partly open situations where suitable trees and understorey persist.

Insects and other arthropods dominate the diet. Recorded prey include grasshoppers, crickets, mantids, beetles, termites and bees. The species also takes nectar and may steal food caught by other birds, a behaviour known as kleptoparasitism.

Square-tailed drongos commonly hunt from a lookout perch, making short sallies after prey in the air, foliage or on the ground before often returning to a perch.

Square-tailed drongos are usually encountered singly or in pairs and are active, conspicuous and vocal within their territories. They also frequently join mixed-species feeding flocks, where their calls appear to play an important role in keeping the flock together.

A study published in 2015 in the East Usambara Mountains of Tanzania found square-tailed drongos in 86% of mixed-species flocks. Flocks containing the species were larger, especially in continuous forest, and the drongos’ calls attracted other flocking birds. The square-tailed drongo therefore acts as a central flock species: its presence and vocalisations help other species assemble and remain together.

Pairs are monogamous and both adults help defend the nesting territory. The nest is a shallow, strongly woven cup of fine plant material, rootlets, twigs, fibres, lichen and spider silk, usually suspended in a horizontal fork in a tree, often near the edge of dense forest.

The clutch most often contains two eggs, although three to four have been reported. In southern Africa, egg-laying has been recorded mainly from September to January, with a peak around October–November. Both parents contribute to caring for the young, while detailed incubation and fledging periods remain poorly documented across much of the range.

The square-tailed drongo is classified as Least Concern on the IUCN Red List. It has a broad distribution through eastern and southern Africa and remains locally common in suitable forest and woodland. No global population estimate is available.

Forest loss and degradation can affect both the species and the mixed-species flocks it joins. In the East Usambara Mountains, square-tailed drongos were less common in fragmented forest, and those fragments also held less diverse, less stable flocks than continuous forest. This shows how the loss of a central flock species can have wider ecological effects even when the species itself is not globally threatened.