• 9 species in tropical Asia & Africa
• DR personal total: 5 species (55%), 1 photo

Molecular studies have recently discovered new and ancient lineages of birds that had not previously been anticipated. One of these — about which we are still learning — is a lineage (or "clade") of flycatchers in Africa and tropical Asia that have been formally named the Stenostiridae (Fuchs et al. 2009). These are mostly tropical birds, and many behave like fantails, spreading and twitching their tails as they forage through the canopy of tall forests. An example in central Africa is Blue-and-white Crested-Flycatcher (left; often called "White-tailed Blue Flycatcher," see below). It is one of five species in the genus Elminia, which make up about half of the stenostirids.

The five species of crested-flycatchers in genus Elminia were previously assigned to the Monarch family Monarchidae. Many monarchs are fantails in the genus Rhipidura. The Monarchs arose in Australasia while the Stenostirids apparently arose in either Africa or Asia, and the two groups are not closely related at all (Fuchs et al. 2009). It has now been discovered that one of the birds traditionally called a "fantail" in genus Rhipidura — Yellow-bellied Fantail "R. hypoxantha" of the eastern Himalayas — is actually a stenostirid. It is now returned to its original genus (Chelidorynx) and becomes the ninth member of the Stenostiridae (Fuchs et al. 2009).

Sibley & Ahlquist (1990) and Sibley & Monroe (1990), working with DNA-DNA hybridization techniques, found that the two canary-flycatchers in the genus Culicicapa, from the Oriental region, did not group with other muscicapid flycatchers, with which they are traditionally been placed. They put them with the Australo-Papuan robins [Petroicidae, then called Eopsaltriidae] since the DNA hybridization results grouped there. They did not anticipate the relationships that have now been discovered.

The two canary-flycatchers — Citrine Canary-Flycatcher of the Philippines and Greater Sundas (right, photo © Blake Matheson) and Gray-headed Canary-Flycatcher C. ceylonensis of southern Asia — are small, active, and conspicuous flycatchers in montane forests within their range. They perch upright, making typical flycatching forays beneath of the canopy, and are often a member of mixed bird parties; Rasmussen & Anderton (2005). They thus resemble many muscicapid flycatchers, and do not behave like fantails. Beresford et al. (2005) were the first to show, through molecular evidence, that Culicicapa and Elminia were not only related to each other, but were closely related to a southern African enigma, the Fairy Warbler (or Fairy Flycatcher) Stenostira scita. Sibley & Monroe (1990) had put Stenostira in the Acrocephalinae subfamily of the Old World Warblers "Sylviidae." The findings of these totally unexpected relationships overturned the apple cart.

Beresford et al. (2005) proposed calling this new group the family Stenostiridae; Fuchs et al. (2009) proposed the formal description. The clade has been recovered in numerous studies and now appears certain. For the moment, we know that the members include

• five species of Elminia crested-flycatchers [three of which are sometimes listed in genus Trochocercus] in Africa,
• one species Stenostira fairy-flycatcher in Africa,
• two species of Culicicapa canary-flycatchers in Asia, and
• one species of Chelidorynx fantail from Asia.

To date there is no morphological character to unambiguously define this family, although it is defined genetically (Fuchs et al. 2009). The species with the oldest name is Stenostira, so the family becomes the Stenostiridae. An English name for the family might be the Fairy Flycatchers. I like the ring of the name, although I often use the term "stenostirids" for this group. This family does appear to include a radiation of flycatcher-like birds that have evolved to fit niches within forested settings that are filled by species in other families elsewhere.

As we have seen, two species "blue-flycatcher" [Elminia] and three species of "crested-flycatcher" [formerly Trochocercus] are in this family. These five are now merged in Elminia. Dickinson (2003) proposed that all Elminia flycatchers now be called "crested-flycatchers" (or "crested flycatchers" for those who don't hyphenate). This has the effect of changing the English name of "African Blue-Flycatcher" to Blue Crested-Flycatcher, and the name "White-tailed Blue-Flycatcher" to Blue-and-white Crested-Flycatcher. I very much approve of these changes, because there are 17 species of Cyornis in Asia that are called "Blue-Flycatcher," and these are all muscicapid flycatchers [family Muscicapidae]. Now all the "Crested-Flycatchers" are stenostirids, since the remaining two Trochocercus are now called "Paradise-Flycatchers: (Dickinson 2003).

This lineage of flycatchers is interesting in that the currently-known members are African endemics (Stenostira, Elminia) and Indo-Malayan species (Chelidorynx, Culicicapa). The molecular evidence is that this split between groups occurred synchronously (Fuchs et al. 2009). Those authors draw a parallel between the rockjumpers of South Africa (Chaetops) and rail-babbler of southeast Asia (Eupetes), which appear to be more closely related to each other than to anything else (Fjeldså & Bowie 2008). But that divergence occurred much earlier in the evolutionary time-scale.

What other birds may also be in this family? Urban et al. (1997) suggested that the two species of tit-flycatchers in Africa (genus Myioparus) might be related to Stenostira. This has not been tested (Beresford et al. 2005). What of the three Erythrocercus flycatchers of Africa, which are not monarchs (Pasquet et al. 2002)? One wonders how many other 'flycatchers' or 'fantails,' currently assigned to other families, may turn out to be stenostirids?

Photos: The Blue-and-white Crested-Flycatcher Elminia albicauda was at Ruhiza, Bwindi-Impenetrable Forest NP, Uganda, on 19 July 2002. Blake Matheson photographed the Citrine Canary-Flycatcher Culicicapa helianthea on 31 Dec 2005 at Mt. Pollis, Luzon, Philippines. Photos © Don Roberson and canary-flycatcher photo © Blake Matheson, used with permission; all rights reserved.

Bibliographic note: There is no "family book" for this newly discovered family. The species in it were considered within the scope of their traditionally assigned families in the Handbook of the Birds of the World series.

Literature cited:

Beresford, P., F.K. Barker, P.G. Ryan, and T.M. Crowe. 2005. African endemics span the tree of songbirds (Passeri): molecular systematics of several evolutionary 'enigmas.' Proc. R. Soc. B. 272: 849-858.

Dickinson, E., ed. 2003. The Howard & Moore Complete Checklist of the Birds of the World. 3d ed. Princeton Univ. Press, Princeton, N.J.

Fuchs, J., E. Pasquet, A. Couloux, J. Fjeldså, and R.C.K. Bowie. 2009. A new Indo-Malayan member of the Stenostiridae (Aves: Passeriformes) revealed by multilocus sequence data: biogeographical implications for a morphologically diverse clade of flycatchers. Molec. Phylog. Evol. 53: 384-393.

Fjeldså, J., and R.C.K. Bowie. 2008. New perspectives on the origin and diversification of Africa's forest avifauna. African J. Ecol. 46: 235-247.

Pasquet, E., A. Cibois, F. Baillon, and C. Erard. 2002. What are African monarchs (Aves: Passeriformes)? A phylogenetic analysis of mitochondrial genes. Comptes Rendus Biologies 325: 107-118.

Rasmussen, P.C., and J.C. Anderton. 2005. Birds of South Asia: the Ripley Guide. 2 vols. Smithsonian Instit., Washington, D.C., and Lynx Edicions, Barcelona.

Sibley, C.G., and J.E. Ahlquist. 1990. Phylogeny and Classification of Birds: a Study of Molecular Evolution. Yale Univ. Press, New Haven, CT.

Sibley, C.G., and B.L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the Worlds. Yale Univ. Press, New Haven, CT.

Urban, E.K., C.H. Fry, and S. Keith. 1997. The Birds of Africa. Vol. 5. Academic Press, New York.