Birds of par­adise

The King of Sax­ony is one of 38 amaz­ing bird of par­adise species in Pa­pua New Guinea that at­tracts a mate with a cu­ri­ous dance and feather dis­play.

BBC Wildlife Magazine - - Contents - By Sheena Har­vey

Find out why the spec­tac­u­lar King of Sax­ony stands out among Pa­pua New Guinea’s birds of par­adise

The climb up 300m had taken over an hour and three tum­bles. By the time we ar­rived at the top of the ridge, we were cov­ered in mud and pant­ing heav­ily. Well, most of us were. Our guide, Joseph Tono, who ended up car­ry­ing a lot of our gear to save it from crash­ing onto the for­est floor when we slipped, was mud-free and breath­ing nor­mally.

Early that morn­ing, our jour­ney had started from a lodge si­t­u­ated 2,130m up in the High­lands of Pa­pua New Guinea. We were now at 2,430m and ap­pre­ci­at­ing how thin the air is at that height. Joseph’s ac­cli­ma­tised lungs were prob­a­bly 25 per cent big­ger than ours, and he was def­i­nitely more sure-footed on the sod­den track.

Once at the top of Ron­don Ridge, we be­gan to scan the tree­tops for birds of par­adise – or BoPs as they are af­fec­tion­ately known – which live at these lofty heights. I par­tic­u­larly wanted a look at a King of Sax­ony, and Joseph had said our chances were good, if the low cloud and rain let up.

Trails of mist drifted through the trees, giv­ing the mon­tane for­est an eerie feel. The wa­ter­logged air dis­torted the calls of un­seen birds that Joseph nev­er­the­less iden­ti­fied as black sick­lebill, white-winged robin and bar­tailed cuckoo-dove. After an hour, the sun grad­u­ally be­gan to drive away the cloud and the for­est emerged in all its glis­ten­ing glory. Now we could see a par­tic­u­lar bare branch that Joseph said was a favourite perch­ing post of a King of Sax­ony. Sure enough, he picked out the dis­tinc­tive call amongst the am­bi­ent bird sound, and the show was on.

Song and dance

My cu­rios­ity with a bird that some might con­sider one of the least colour­ful of the 38 species of BoPs in New Guinea, be­gan when I saw a YouTube video of a male’s courtship dis­play. It was made by the Cor­nell Lab of Or­nithol­ogy, part of Cor­nell Uni­ver­sity in New York state, which has been con­duct­ing a long-term bird-of-par­adise project. The film showed a crow-sized bird, at the top of a dead branch, with a bright yel­low breast and two ex­tremely long, thin ‘feath­ers’ rising from be­hind its eyes. Its call was a raspy, squeaky, whistling sound de­liv­ered with beak wide open, show­ing a pale bluey­green in­te­rior. Hav­ing shouted from its perch, it dropped down onto a vine, where it bounced up and down, calling and fluff­ing its neck feath­ers into a ruff.

All very im­pres­sive, but it was those long feath­ers that I found most fas­ci­nat­ing. They are an­chored to the bird’s head in shal­low de­pres­sions, and the power to move them around in­de­pen­dently seems to be in­vested solely in the skin over the skull.

The plumes them­selves are less like con­ven­tional feath­ers and more like rigid leaf-shapes – there are 30 to 40 of them at­tached to one side of a ‘stiff wire’.

Birds of par­adise first came to wide­spread no­tice out­side of or­nitho­log­i­cal cir­cles when they fea­tured in Lords of the Air, the eighth episode of David At­ten­bor­ough’s Life on Earth se­ries, first broad­cast 40 years ago.

These doc­u­men­taries es­tab­lished At­ten­bor­ough’s in­ter­na­tional rep­u­ta­tion as a tele­vi­sion nat­u­ral­ist and in­tro­duced the Bri­tish pub­lic to pre­vi­ously un­seen won­ders.

One of a kind

At­ten­bor­ough was en­tranced by the ex­otic dis­plays put on by male birds of par­adise to at­tract the at­ten­tion of a fe­male. In an ar­ti­cle in New Sci­en­tist, he declared, “Most ex­tra­or­di­nary of all is the King of Sax­ony bird of par­adise. His body is com­par­a­tively drab, but he grows two huge quills from the back of his head, each notched with blue enamel-like plates; there is noth­ing like them in the bird world.”

Cou­pled with these bizarre ap­pendages – which bear lit­tle re­sem­blance to the body adorn­ments of even the showier birds of par­adise – the King of Sax­ony is also

Hav­ing shouted from its perch, it dropped down onto a vine, calling and fluff­ing its neck into a ruff.

unique in its genus of Pteri­dophora.

Birds of par­adise be­long to a group of birds known as passer­ines, which comes from the Latin passer, mean­ing ‘spar­row’, there­fore spar­row-like. Passer­ines make up more than half of all bird species as the term cov­ers any­thing that perches. What most dis­tin­guishes them is their aniso­dactyl toes – three fac­ing for­wards and one back. These en­able the bird to grip and, in ad­di­tion to strength­ened legs, the rest­ing po­si­tion of their feet is a clenched one, so they can main­tain a hold even when asleep.

Food fight

Be­fore our stay near the town of Mount Ha­gen and hike up to Ron­don Ridge, we were stay­ing at Ku­mul Lodge in Enga Prov­ince, where a fruit-stocked bird ta­ble pro­vided an ir­re­sistible break­fast draw to a panoply of bird species. It was a gen­tle in­tro­duc­tion to the won­ders of birds of par­adise. Though it could be said to be cheat­ing, given the ef­forts needed to track down BoPs in the wild, it did have the ad­van­tage of al­low­ing close and pro­longed views of the birds and their be­hav­iour.

A num­ber of brown sick­lebills came to the ta­ble – birds of par­adise that have evolved the abil­ity to peel open and pen­e­trate the pods of cap­su­lar fruit. That’s not to say they pass up a meal of fruit that’s been cut open for them, of course. They’ve learned to use their curved beaks to ex­cise a morsel of mango from its skin and toss it into the air, so they can catch and swal­low it.

Rib­bon-tailed as­trapias also vis­ited daily, the males some­how nav­i­gat­ing a path through the trees with­out dam­ag­ing their two mag­nif­i­cent white tail stream­ers. A ju­ve­nile rib­bon-tail, whose tail feath­ers had not yet reached their full length, was pur­sued re­lent­lessly by a ma­ture adult de­ter­mined to drive it away. His noisy and bois­ter­ous de­fence of his ter­ri­tory con­tin­u­ally scat­tered the smoky hon­eyeaters, Brehm’s tiger par­rot and Belford’s melidectes that were also at­tempt­ing to en­joy the fruit buf­fet.

Colour com­bi­na­tions

The fact that New Guinea – now di­vided into West­ern New Guinea ad­min­is­tered by In­done­sia and the in­de­pen­dent state of Pa­pua New Guinea – is an is­land group with an agree­able cli­mate and dense forests abun­dantly blessed with fruit­ing trees, is one of the se­crets why birds of par­adise evolved there al­most ex­clu­sively. Only in the most north-east­erly tip of Aus­tralia can you

Males know what they need to do to ac­quire a mate, and will prac­tise their calls and dances.

find any other BoP species – the par­adise and Vic­to­ria’s ri­flebirds and the trum­pet manu­code. All three species are black with iri­des­cent pur­ple or green feath­ers; although ar­rest­ing in their col­oration, they have not evolved the va­ri­ety of hues seen in species that live ex­clu­sively in New Guinea.

The Cor­nell Lab’s project (which in­cludes the Aus­tralian species) ex­plains the rea­sons be­hind fan­tas­tic feather forms. The the­ory of evo­lu­tion by nat­u­ral se­lec­tion, as de­scribed by nat­u­ral­ist Al­fred Rus­sel Wal­lace in 1858, ex­plains how phys­i­cal traits that ad­van­tage for­ag­ing or sur­vival against preda­tors oc­cur by chance mu­ta­tions passed on in the genes of the suc­cess­ful an­i­mals.

Though Wal­lace did not coin the term ‘nat­u­ral se­lec­tion’ he did de­scribe how species evolve through en­vi­ron­men­tal pres­sures that favour one char­ac­ter­is­tic over an­other. So, one branch of a fam­ily could de­velop in quite a dif­fer­ent way to an­other sim­ply be­cause of lo­cal liv­ing con­di­tions. His work on this dove­tailed with Charles Dar­win’s, and the 1858 pa­per ex­plain­ing evo­lu­tion was jointly pub­lished.

The prob­lem with birds of par­adise, and the quirky ap­pear­ance and be­hav­iour of the males fit­ting into the model of nat­u­ral se­lec­tion, is that the ex­treme feather mod­i­fi­ca­tions and elab­o­rate courtship dances ben­e­fit nei­ther for­ag­ing nor elud­ing preda­tors. Com­plex plumage can hin­der progress in dense for­est and aid de­tec­tion by other species – good rea­sons not to de­velop in such an ex­trav­a­gant way.

Ladies’ choice

This is where Dar­win’s as­ser­tions that the com­pe­ti­tion within mem­bers of the same species to mate and pass on their genes also in­flu­ences evo­lu­tion, in this case by sex­ual se­lec­tion on the part of the fe­males.

This has come to be ac­cepted as a log­i­cal hy­poth­e­sis, although there is still a ques­tion mark over ex­actly what dic­tates the fe­male birds’ choices of mate. Are they pick­ing elab­o­rately plumed males sim­ply be­cause they are visu­ally at­trac­tive and dance well, or is it that these things in­di­cate strength, and a like­li­hood that the cou­pling will pro­duce young­sters ro­bust enough to sur­vive?

What­ever the rea­sons, the males know what they need to do to ac­quire a mate, and will prac­tise their calls and dances even when there are no fe­males present. This was the case with our Ron­don Ridge King of Sax­ony. We were out­side the breed­ing sea­son and Joseph could not de­tect a fe­male any­where in the vicin­ity, but the male we were watch­ing still went through his paces.

The­o­ries of sex­ual se­lec­tion may ex­plain why these birds have de­vel­oped with such seem­ingly use­less coats of many colours and pe­cu­liar chore­og­ra­phy, but why did they evolve in such dif­fer­ent ways? This as­pect speaks to the lush­ness of New Guinea, its geo­graph­i­cal fea­tures and its iso­la­tion. A vast acreage of im­pen­e­tra­ble rain­for­est and mon­tane habi­tat, plen­ti­ful wa­ter and a rich, bio­di­verse plantlife pro­vides an abun­dance of food and places to live.

The king of Sax­ony’s favoured dwelling place is the cloud forests of the cen­tral spine of Pa­pua New Guinea. There, safe from preda­tors, apart from the oc­ca­sional hu­man, it is free to as­sume its post, wave its flags and bounce its way to pro­duc­ing the next gen­er­a­tion of birds that will de­light any­one who climbs high enough to see them.

SHEENA HAR­VEY is BBC Wildlife’s Edi­tor. Her trip was or­gan­ised by Reef & Rain­for­est cour­tesy of Pa­pua New Guinea Tourism Pro­mo­tion Au­thor­ity.

FIND OUT MORE The Cor­nell Lab BoP project: bird­sof­par­adis­e­pro­ject.org

Above: used to im­press dur­ing courtship dis­plays, the tail feath­ers of the male rib­bon­tailed as­trapia can be three times the length of its body. Top left: Belford’s melidectes (or hon­eyeater) is just one species happy to take ad­van­tage of the fruit on of­fer at Ku­mul Lodge in Enga Prov­ince.

A Belford’s melidectes perch­ing on a branch, us­ing its aniso­dactyl toes to hold it­self in place.

The rag­giana bird of par­adise is Pa­pua New Guinea’s national bird and its out­line is de­picted in flight on the coun­try’s flag.

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