Honeyguides, family Indicatoridae, are well known as obligate brood parasites. In the case of the Brown-backed Honeyguide (Prodotiscus regulus) the known hosts are warblers (Camaroptera, Cisticola), sunbirds (Nectarinia), and Yellow-throated Petronia (Petronia superciliaris) (Short & Horne 2002). Hockey et al. (2005) list the Bar-throated Apalis (Apalis thoracica) as a possible but still unconfirmed host of this honeyguide species. Here we report the sighting of two Brown-backed Honeyguide chicks being fed by one adult Bar-throated Apalis in Zimbawe.
Early morning on 2 February 2014 my husband, Joerg von Chamier and I heard an unusual insect-like sound coming from an Acacia sieberiana tree in our garden, sited in the Kamfinsa area of the northern suburbs in Harare. When we found the source it was a chick of some sort begging for food and fluttering its wings. We saw a Bar-throated Apalis arrive and were amazed to see that it was feeding this rather large chick. From around 8:00 to 9:30 hours we observed two chicks being fed by one somewhat harried Bar-throated Apalis adult. I was able to take photos of one chick at a time being fed mainly winged insects every few minutes (3–7 minute intervals). The chicks followed by the adult would retreat occasionally to within a very thick exotic conifer about 3∙5 m above the ground, only to reemerge and continue feeding.
We identified the chick as Brown-backed Honeyguides according to Hockey et al. (2005). Characteristic features leading to the identification were the brown-grey back, orange gape with a pink color inside the mouth, the yellow wash below, and the dark brown eyes. The chicks appeared to be in the final stage of its three-week nestling period. It is interesting to note that the juvenile Brown-backed Honeyguide tail has three outer pairs of creamy yellow and two central pairs of brownish grey rectrices, whereas the adult tail contains two pairs of brown-tipped and otherwise white outer rectrices.
The next morning we observed the same feeding behavior, and the day after there was no sign of the Apalis or the chicks. We have never observed adult Brown-backed Honeybirds in our garden.
Hockey, P.A.R., Dean, W.R.J. & Ryan, P.G. eds. (2005). Roberts’ Birds of Southern Africa. 7th edition. The Trustees of the John Voelcker Bird Book Fund, Cape Town.
Short, L.L. & Horne, J.F.M. (2002). Brown-backed Honeyguide (Prodotiscus regulus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/56106 on 19 May 2014).