Honeyguides (familyIndicatoridae) are a family of birds in the orderPiciformes. They are also known asindicator birds, orhoney birds, although the latter term is also used more narrowly to refer to species of the genusProdotiscus. They have anOld World tropical distribution, with the greatest number of species inAfrica and two inAsia. These birds are best known for their interaction with humans. Honeyguides are noted and named for one or two species that will deliberately lead humans (but, contrary to popular claims, most likely nothoney badgers[1]) directly to bee colonies, so that they can feast on the grubs andbeeswax that are left behind.
The Indicatoridae were noted for their barbet-like structure and brood-parasitic behavior and morphologically considered unique among the non-passerines in having nine primaries.[2] Thephylogenetic relationship between the honeyguides and the eight other families that make up the order Piciformes is shown in the cladogram below.[3][4] The number of species in each family is taken from the list maintained byFrank Gill,Pamela C. Rasmussen and David Donsker on behalf of theInternational Ornithological Committee (IOC).[5]
Most honeyguides are dull-colored, though some have bright yellow coloring in the plumage. All have light outer tail feathers, which are white in all the African species. The smallest species by body mass appears to be thegreen-backed honeyguide, at an average of 10.2 g (0.36 oz), and by length appears to be theCassin's honeyguide, at an average of 10 cm (3.9 in), while the largest species by weight is thelyre-tailed honeyguide, at 54.2 g (1.91 oz), and by length, is thegreater honeyguide, at 19.5 cm (7.7 in).[6][7][8]
They are among the few birds that feed regularly onwax—beeswax in most species, and presumably the waxy secretions ofscale insects in the genusProdotiscus and to a lesser extent inMelignomon and the smaller species ofIndicator. They also feed onwaxworms which are the larvae of the waxmothGalleria mellonella, onbee colonies, and on flying and crawling insects,spiders, and occasional fruits. Many species joinmixed-species feeding flocks.
Honeyguides are named for a remarkable habit seen in one or two species: guiding humans tobee colonies. Once the hive is open and the honey is taken, the bird feeds on larvae and wax. This behavior has been studied in thegreater honeyguide; some authorities (following Friedmann, 1955) state that it also occurs in thescaly-throated honeyguide, while others disagree.[6] Wild honeyguides understand various types of human calls that attract them to engage in the foraging mutualism.[9] In northernTanzania, honeyguides partner withHadza hunter-gatherers, and the bird assistance has been shown to increase honey-hunters' rates of finding bee colonies by 560%, and led men to significantly higher yielding nests than those found without honeyguides.[10] Contrary to most depictions of the human-honeyguide relationship, the Hadza did not actively repay honeyguides, but instead, hid, buried, and burned honeycomb, with the intent of keeping the bird hungry and thus more likely to guide again.[10] Some experts believe that honeyguide co-evolution with humans goes back to the stone-tool making human ancestorHomo erectus, about 1.9million years ago.[11][10] Despite popular belief,[citation needed] no evidence indicates that honeyguides guide thehoney badger; though videos about this exist, there have been accusations that they were staged.[12][13]
Although most members of the family are not known to recruit "followers" in their quest for wax, they are also referred to as "honeyguides" by linguistic extrapolation.
The breeding behavior of eight species inIndicator andProdotiscus is known. They are allbrood parasites that lay oneegg in a nest of another species, laying eggs in series of about five during a period of 5–7 days. Most favor hole-nesting species, often the relatedbarbets andwoodpeckers, butProdotiscus parasitizescup-nesters such aswhite-eyes andwarblers. Honeyguide nestlings have been known to physically eject their hosts' chicks from the nests and they have needle-sharp hooks on theirbeaks with which they puncture the hosts' eggs or kill the nestlings.[14]
African honeyguide birds are known to lay their eggs in underground nests of other bee-eating bird species. The honeyguide chicks kill the hatchlings of the host using their needle-sharp beaks just after hatching, much ascuckoo hatchlings do. The honeyguide mother ensures her chick hatches first by internally incubating the egg for an extra day before laying it, so that it has a head start in development compared to the hosts' offspring.[15]
^abShort, L.L. and J. F. M. Horne (2020).Greater Honeyguide (Indicator indicator), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
^Short, L.L., J. F. M. Horne, and G. M. Kirwan (2020).Cassin's Honeyguide (Prodotiscus insignis), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
^Dunning, John B. Jr., ed. (2008).CRC Handbook of Avian Body Masses (2nd ed.). CRC Press.ISBN978-1-4200-6444-5.
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