What are the forty species of flightless birds?

There are more than forty species of flightless birds. Here are some examples:

* Ostrich (_Struthio camelus_)

* Emu (_Dromaius novaehollandiae_)

* Cassowary (_Casuarius casuarius_)

* Kiwi (_Apteryx spp._)

* Rheas (_Rhea americana_, _Rhea pennata_, _Rhea tarapacensis_)

* Tinamous (_Tinamus spp._)

* Penguins (_Spheniscus spp., Pygoscelis spp., Eudyptula spp., Megadyptes spp._)

* Alcids (_Alca torda_, _Pinguinus impennis_, _Fratercula arctica_)

* Hoatzins (_Opisthocomus hoazin_)

* Curassows (_Crax spp._)

* Guans (_Penelope spp., Pipile spp._)

* Chachalacas (_Ortalis vetula_, _Ortalis poliocephala_)

* Kagu (_Rhynochetos jubatus_)

* Sunbittern (_Eurypyga helias_)

* Seriemas (_Cariama cristata_, _Chunga burmeisteri_)

* Trumpeters (_Psophia leucoptera_, _Psophia crepitans_)

* Aptornis (_Aptornis defossor_)

* Moa (_Dinornis spp., Emeus crassus_, etc.)

* Elephant birds (_Aepyornis maximus_, etc.)

* Dodo (_Raphus cucullatus_)

* Solitaire (_Pezophaps solitaria_)

* Rodrigues solitaire (_Solitaire pezilla_)

* Great auk (_Pinguinus impennis_)

* Laughing owl (_Sceloglaux albifacies_)

* Strigops parrot (_Nestor meridionalis_)

* Lord Howe Island stick insect (_Dryococelus australis_)

* Chatham Island forget-me-not (_Myosotis chathamensis_)

* Chatham Island akeake (_Olearia traversii_)

* Campbell Island megaherb (_Stilbocarpa polaris_)

* Auckland Island forget-me-not (_Myosotis aucklandica_)

* Antipodes forget-me-not (_Myosotis antipoda_)

* Macquarie Island forget-me-not (_Myosotis macrantha_)

* Heard Island forget-me-not (_Myosotis saxosa_)

* Marion Island forget-me-not (_Myosotis exsul_)

* Bouvet Island forget-me-not (_Myosotis bouvetensis_)

* South Georgia forget-me-not (_Myosotis antarctica_)