Nest Decorations

Bowerbirds are certainly my favorite examples of animals that build elaborate courtship and mating structures, such as the structure shown below being decorated with blue bottle caps by a male satin bowerbird (image credit: Alan Fear).


Also check out this video clip from the BBC showing bowerbirds in the midst of decorating.

Home decorating may not be simply for mate attraction and courtship, however. A recent study of black kites (Milvus migrans) a species of raptor, shows evidence for increased offspring survival with highly decorated nests. In black kites, breeding is usually controlled by social dominance but threats to breeding may include individuals from the same species attempting to takeover territories, trespass, or steal food resources.

Black kite Fight.jpg

Black kite nests are built by mating pairs of birds and are often decorated with man-made objects that are mostly white and plastic. Researchers studied the nests of these birds in Donana National Park to determine if the decorations might be used for more than simply mating or courtship. What they found was that nest decorating was correlated with age, such that young birds built sparsely decorated or undecorated nests. Nest decorations peaked around 10-12 years old and then declined again as the birds aged.

kite nest.gif

The number of offspring raised and their survival were actually higher with greater nest decorations. Trespassers were also found to avoid nests with more decorations resulting in less interactions and time spent away from the nest fighting. The authors concluded that the amount of nest decorations is thought to relay information about social dominance and fighting ability, thereby reducing the risk of trespassers.

kite nest 3.gif

Sergio et al., Raptor Nest Decorations Are a Reliable Threat Against Conspecifics. Science 331: 327-329, 2010.


More like this

tags: evolutionary biology, behavioral ecology, life history, migration, long-distance migration,birds,ornithology,,peer-reviewed research, peer-reviewed paper White-rumped sandpiper, Calidris fuscicollis, chicks on Bylot Island, Nunavut, Canada. Image: Laura McKinnon [larger…
tags:, dichromatism, mating system, plumage color, sex allocation, eclectus parrots, Eclectus roratus, ornithology, birds, avian, parrots Elektra, my female Solomon Islands eclectus parrot, Eclectus roratus solomonensis. This is the smallest and most distinctively marked of…
tags:, Black-throated Blue Warbler, Dendroica caerulescens, social information, habitat selection, vegetation structure, location cues, dispersal, Matthew G Betts Male Black-throated Blue Warbler, Dendroica caerulescens, with nestlings. Image: S. Maslowski, USFWS [larger…
Electric fish, Brienomyrus brachyistius, produce tiny electric signals from an organ in their tails that can be used to communicate and convey social status. They can also be used attract a mate, as reported in a study by Wong and Hopkins in the Journal of Experimental Biology. (The ghetto picture…