European Honey Buzzard
The European Honey Buzzard (Pernis apivorus) is a medium-sized woodland raptor, the birds tracked from the Veluwe NL project weighed 700-1050g at a wing chord of 387-425 mm, corresponding with wingspan 1.2 to 1.45m 1,2.
Sexes show large overlap in size and weight, though females average a bit larger. Dorsal feathers in males generally show more (bluish) grey, females are predominantly brown. Ventral colour varies from chocolate to white with intermediate bars, blocks and strokes.
Compared to similar sized buzzards (Buteo sp.) the Honey Buzzard has a slim body, a long neck, broader wing, longer tail and thick short legs.
The Honey Buzzard is a long-distance migrant wintering in rainforests of Central Africa. Its low weight/wing surface ratio (wing load) enables it to make use of atmospheric updrafts by soaring. This strategy ensures minimal energy use and is vital for long-distance migration. Adult Honey Buzzard navigate towards bottleneck sites and tracks of our project birds suggest that they cover no less than 92% of migration by soaring.
Immature birds apparently stay in Africa for one or several years. Returning adults arrive in May and occupy territories in all kinds of Palearctic forests from the Mediterranean up to Scandinavia-Russia. Territorial males advertise by a typical undulating flight with stunningly quick flapping wing beats overhead at the curve’s peak. Breeders face a narrowly fenced “100 days” season from egg laying in the second half of May till fledging one or two chicks in the second half of August. Partners share breeding duties, females taking the larger share (55-65% depending on stage, Veluwe NL project data).
Principal food consists of social wasp larvae eaten from combs, mainly dug from nests in soil or rotten wood cavities. This is where some morphological properties come in handy: the long neck and firm “digging” leg with rather flat toenails together with unique protective facial feathering resembling the scales of a reptile. Wasps usually are best exploited during the second half of the breeding season (chick-raising). Years of low wasp abundance show reduced breeding success through mortality or abandonment of chicks with seriously retarded growth1. The diet also includes slow vertebrate prey, predominantly frogs and (mostly naked) songbird-nestlings. To an unknown extent breeders feed on spiders and insects (or larvae) (butterflies, grasshoppers, crickets, beetles) when walking on the ground1.
The specialist feeding on poikilothermic prey and the importance of soaring flight suggest Honey Buzzards are extremely dependant on ‘suitable’ meteorological (or atmospheric) conditions for a successful completion of all stages of their annual cycle. The species therefore presents a particularly interesting opportunity to study the seasonal effects (and their interactions) of environmental changes on migratory species. UvA-BiTS hereby provides unique opportunities to study how Honey Buzzard react to their environment on different spatiotemporal scales.
1BWPi 2004. The birds of the western Palearctic interactive. DVD Bird guides, Shrewsbury.
2 Mebs T. & Schmidt D. 2006. Die Greifvögel Europas, Nordafrikas und Vorderasiens. Biologie, Kennzeichen, Bestände. Kosmos, Stutgart.
Back in Europe: UvA-BiTS Honey Buzzard photographed at the Strait of Gibraltar
Wednesday, May 15th, 2013
Female deserts brood, male raises chicks
Friday, May 13th, 2011
Wintering range in Sierra Leone
Friday, May 13th, 2011