Head to head
Lyrebird vs Bird-of-paradise
The lyrebird of Australia and the birds-of-paradise of New Guinea are both products of intense sexual selection, where females do all the parenting and choose mates on the quality of a display. But the two groups took that pressure in different directions, one toward sound and one toward spectacle.
| Lyrebird | Bird-of-paradise | |
|---|---|---|
| Where | Eastern Australian forests | New Guinea and nearby; a few in Australia |
| Species | 2 | About 45 |
| Main display tool | Sound: an elaborate mimic song | Sight: plumage, colour, and dance |
| Male plumage | Brown body, ornate lyre-shaped tail | Extravagant plumes, iridescence, capes, wires |
| Display site | A cleared earth display mound | A canopy lek or a cleared forest-floor court |
| Parenting | Female alone | Female alone in most species |
| Time to full display form | About 7 years for the tail | 5 to 7 years for full plumage |
| Main human impact | Old-growth forest loss; fire | Nearly wiped out for the plume and hat trade |
Lyrebird vs Bird-of-paradise: common questions
Are lyrebirds and birds-of-paradise related?
Only distantly. Both are passerines, or perching birds, and both belong to the oscine songbirds, but they sit on separate early branches of that group. The lyrebirds are part of an ancient Australian radiation of songbirds, close to the scrub-birds. The birds-of-paradise are on the branch that also leads to crows, and are closest to the crows and to the Australian mudnesters. Their shared feature, jaw-dropping male display driven by female choice, evolved independently in each lineage, which is why one group specialises in sound and the other in appearance rather than both doing the same thing.
Which has the more impressive display?
It depends on the sense you weight. For sound, the lyrebird is unmatched by any bird or indeed any animal: a displaying male delivers a long, complex, continuously varied song that reproduces the calls of many other species so exactly that they respond, interwoven with mechanical and human noises it has learned. For sight, the birds-of-paradise are unmatched: the transformation of the superb bird-of-paradise into a bouncing black oval with a blue smile, the parotia ballerina dance, and the King of Saxony's metre-long head wires are among the strangest visual displays in nature. Neither is objectively better; they are the two extremes of what sexual selection can build.
Why do the males display so much while the females look plain?
In both groups the females raise the young entirely alone, so a male offers nothing but his genes. That removes any advantage to a female in choosing a helpful or well-camouflaged mate and leaves her free to choose on display quality alone, which sets off a runaway process: any heritable trait that makes a male more attractive spreads, and over generations the displays become more and more exaggerated. The females stay drab because they still have to sit on an exposed nest and avoid predators, so natural selection keeps them cryptic while sexual selection pushes the males the other way. Young males also look female-like for years, which lets them practise at display sites without being attacked as rivals.