I cannot complete this blog without having a post dedicated entirely to bowerbirds. Bowerbirds are exceptional in that they display a multifaceted and extremely entertaining approach to sexual display. Bower building and ornamentation is what they are most famous for, but dancing and strange vocal displays that often incorporate mimicry are also utilised to tempt females into reproduction (Marshall 1954).
Bowers
The first and most important part of the sexual display exhibited by male bowerbirds, is the ability to build a bower (where courtship and copulation take place) of sufficient quality to attract a prospective mate (Borgia 1985, Marshall 1954). Males are highly territorial and frequently destroy and steal decorations from other bowers, so the ability of a male to build, defend and display in a highly decorated bower is thought to provide the female information as to the overall quality of the male (Borgia 1985, Robson et al. 2005). It has been shown that females are more attracted to males who have high quality bowers, and it is these males who account for the majority of matings (Borgia 1985).
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| The male Fawn-breasted Bowerbird (Chlamydera cerviniventris) creates his 1-2 foot long tunnel with an open top, known as an avenue-style bower, decorated with bright green leaves. Image sourced from http://animals.sandiegozoo.org/animals/bowerbird. Viewed on 11th March 2017. |
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| The bower of a Great Bowerbird (Chlamydera nuchalis) (the largest of the bowerbirds) from Northern Australia is decorated primarily with white and grey objects such as snail shells and pebbles. Photo by Peter Rowland http://australiaswildlife.com/2016/05/bowerbirds-of-australia/. Viewed on 12th March 2017. |
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| The incredible bower of the male Satin Bowerbird (Ptilonorhynchus violaceus). Image sourced from: http://www.viralforest.com/bower-bird/. Viewed on 12th March 2017. |
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| The 'totem' bower of the Golden Bowerbird (Prionodura newtoniana) of Far North Queensland can be up to 2m high and is decorated with lichen and freshly plucked flowers. Photo by Tim Laman, http://timlaman.photoshelter.com/image/I00004AVpNp1wFWk. Viewed on 11th March 2017.
up
to 2 m high, decorated with lichen and freshly plucked flower - See
more at:
http://www.australianwildlife.org/wildlife/golden-bowerbird.aspx#sthash.jTZwvNR5.dpuf
up
to 2 m high, decorated with lichen and freshly plucked flower - See
more at:
http://www.australianwildlife.org/wildlife/golden-bowerbird.aspx#sthash.jTZwvNR5.dpuf
up
to 2 m high, decorated with lichen and freshly plucked flower - See
more at:
http://www.australianwildlife.org/wildlife/golden-bowerbird.aspx#sthash.jTZwvNR5.dpuf
up
to 2 m high, decorated with lichen and freshly plucked flower - See
more at:
http://www.australianwildlife.org/wildlife/golden-bowerbird.aspx#sthash.jTZwvNR5.dpuf
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| Perhaps the most impressive of all bowers, the giant bower of the Vogelkop Bowerbird (Amblyornis inornata) is a true masterpiece! Make sure you watch the video to find out more and have your mind blown. Photo by Ingo Arndt, http://www.audubon.org/news/see-rare-extraordinary-and-natural-photos-natgeos-new-book. Viewed on 10th March 2017. |
Display
If the male manages to get past the first stage of impressing the female with his architectural and adornment skills, he then gets the chance to perform his display to 'seal the deal' so to speak, and copulate. Research has shown that the intensity and aggression of the male Satin Bowerbird's (Ptilonorhynchus violaceus) display preferred by the female, varies with age and experience and that a successful courtship may be the result of the male reading the female's reaction to his display and adjusting it accordingly (Coleman et al. 2004, Patricelli 2004, Walsh et al. 2002) . This theory of variable female preference has been implicated as a possible driver of the evolution of multifaceted male displays (Coleman et al. 2004, Patricelli 2004, Walsh et al. 2002).
If the male manages to get past the first stage of impressing the female with his architectural and adornment skills, he then gets the chance to perform his display to 'seal the deal' so to speak, and copulate. Research has shown that the intensity and aggression of the male Satin Bowerbird's (Ptilonorhynchus violaceus) display preferred by the female, varies with age and experience and that a successful courtship may be the result of the male reading the female's reaction to his display and adjusting it accordingly (Coleman et al. 2004, Patricelli 2004, Walsh et al. 2002) . This theory of variable female preference has been implicated as a possible driver of the evolution of multifaceted male displays (Coleman et al. 2004, Patricelli 2004, Walsh et al. 2002).
Bowerbirds and the behaviour they display are extremely diverse and what I have shown you here is just a glimpse into their complexity. As Darwin predicted, all evidence points towards a combination of female choosiness and male competition resulting in the exceptional behaviours and traits we see in bowerbirds. I have added some videos below that sum up why I love bowerbirds so much. Where I grew up there are lots of Satin Bowerbirds and the first time I found one of their bowers I was absolutely amazed. I can describe all the incredible things they do, but it is only fully appreciated when you see what they do. Enjoy!
The male satin bowerbird's (Ptilonorhynchus violaceus) display https://www.youtube.com/watch?v=_H9TyXiXM2k. Viewed on 11th March 2017.
The male vogelkop bowerbird (Amblyornis inornata) shows us why he is so incredible! https://www.youtube.com/watch?v=E1zmfTr2d4c. Viewed on 10th March 2017.
The flame bowerbird's (Sericulus aureus) bizarre and mesmerising display https://www.youtube.com/watch?v=1XkPeN3AWIE. Viewed on 11th March 2017.
References
Borgia, G. 1985, "Bower quality, number of decorations and mating success of male satin bowerbirds (Ptilonorhynchus violaceus): an experimental analysis", Animal Behaviour, vol. 33, no. 1, pp. 266-271.
Coleman, S.W., Patricelli, G.L. & Borgia, G. 2004, "Variable female preferences drive complex male displays", Nature, vol. 428, no. 6984, pp. 742-745.
Marshall, A.J. 1954, Bower-birds: their displays and breeding cycles, Clarendon Press, Oxford.
Robson, T.E., Goldizen, A.W. & Green, D.J. 2005, "The multiple signals assessed by female satin bowerbirds: could they be used to narrow down females' choices of mates?", Biology Letters, vol. 1, no. 3, pp. 264-267
Patricelli, G.L. 2004, "Female signals enhance the efficiency of mate assessment in satin bowerbirds (Ptilonorhynchus violaceus)", Behavioral Ecology, vol. 15, no. 2, pp. 297-304.
Walsh, G., Borgia, G., Patricelli, G.L. & Uy, J.A.C. 2002, "Sexual selection Male displays adjusted to female's response", Nature, vol. 415, no. 6869, pp. 279-280.
The Vogelkop bowerbird’s bower is absolutely incredible! Do you know if anyone has looked in the ontogeny of bower building in this group?
ReplyDeleteThe main information I found about this was on the Satin Bowerbird - the most studied of the bowerbirds. They take 7 years to mature - and this is thought to be due to the time it takes for them to hone their bower building skills. Immature males look like females, so are often welcomed by mature males into their bowers, where the mature male can practice their display and the immature male can inspect the construction of a well built bower.
DeleteBowers built by immature males are poorly constructed from inappropriate materials and this indicates they need time to build their skills and knowledge. Older immature males have apparently been seen "instructing" younger birds on bower building technique where a communal bower building site is used.
The fact that large intraspecific variation is present between bowers and many of the components of bower building and display are learned, has led to the belief that bower style is a "cultural" trait. Another piece of evidence to back this up is that when males of another species of bowerbird are in the vicinity, they tend to copy the style of bower and ornamentation displayed by the resident species.
Hope this sort of answers your question. There is still lots to learn about these incredible creatures I think!