David Gallan / Male Satin bowerbird (Ptilonorhynchus violaceus) courting female on suburban street verge, bower filled with blue plastic, Australia, October 2018.

Steven David Miller / Satin bowerbird (Ptilonorhynchus violaceus) female inspecting bower and blue objects collected by male from nearby campsites. Ulladulla, New South Wales, Australia. July.

Steven David Miller / Satin bowerbird (Ptilonorhynchus violaceus) female inspecting bower and blue objects collected by male from nearby campsites. Ulladulla, New South Wales, Australia. July.

Steven David Miller / Satin bowerbird (Ptilonorhynchus violaceus) male with blue bottle top in beak, tending to bower to attract female. Ulladulla, New South Wales, Australia. July.

Oriol Alamany / Satin bowerbird (Ptilonorhynchus violaceus), Green Mountains rainforest, Lamington National Park, Rainforests of Australia UNESCO World Heritage Site, Queensland, Australia

Sylvain Cordier / Satin bowerbird (Ptilonorhynchus violaceus), male building his bower to attract females with blue objects, Queensland, Australia

Sylvain Cordier / Satin bowerbird (Ptilonorhynchus violaceus) male building bower, arranging feathers, Queensland, Australia.

Roger Powell / Satin bowerbird (Ptilonorhynchus violaceus) male standing on a log. Immature growing into sixth year adult plumage and inspecting edge of bower, Werribee, Victoria, Australia

Tim Laman / Crested cnemophilus (Cnemophilus macgregorii) female, Papua New Guinea.

David Tipling / Crested Satinbird (Cnemophilus macgregorii) male calling in, fruiting tree, Kumul Lodge, Western Highlands, Papua New Guinea

David Tipling / Crested Satinbird (Cnemophilus macgregorii) female at Kumul Lodge, Western Highlands, Papua New Guinea

David Tipling / Satin bowerbird (Ptilonorhynchus violaceus) male, standing at bower in rainforest, collecting blue items as part of courtship display, Lamington National Park, Australia.