Sticks and tricks: Bowerbirds use interior design and optical illusions to attract females

Human men aren’t the only ones to show off for the ladies.  In fact, their stabs at romance seem a bit shabby when compared to the courtship displays bowerbirds put on for females they are trying to charm.

Imagine if a man built you an entire house and put all of your favorite things in it to get you on his good side?  A male bowerbird does just that, building a shelter or “bower” of sticks and elaborately decorating it with anything he can find to impress the female in question:

Bowerbird 1

Bower of a Vogelkop bowerbird (Amblyornis inornata) decorated with natural and man-made objects

But that’s not all – it turns out that bowerbirds are very particular about the type and arrangement of objects they place in and around their bowers.  Apparently, female satin bowerbirds prefer the color blue, which is perhaps why they have evolved such strikingly blue eyes (see picture below) so the males seek out blue objects over those of other colors.


Satin bowerbird (Ptilonorhynchus violaceus)

Furthermore, male bowerbirds construct their bowers to create an optical illusion.  Objects are not randomly placed around their court, but instead placed in a size gradient with smaller objects closer to the entrance of the bachelor pad and larger objects farther away.  This optical illusion is called forced perspective, and causes all of the objects to look the same size while the entrance of the bower appears smaller than it actually is.


Satin bowerbird with female

12713-satin_bowerbird-cswHow does this help the male bowerbird snag a female?  If the bower entrance looks smaller than it is, then the male hopping and dancing around the bower entrance in his courtship display will appear larger than he actually is!  Males are very specific about constructing this optical illusion and will in fact recreate it in three days if it is disturbed.

Perhaps we humans should take a leaf out of the bowerbird’s book – I’m sure the ladies wouldn’t complain!




Photographs from Arkive site:

Bowerbird optical illusions:

Animal romance National Geographic page:

Bowerbird informational video from National Geographic:

Bowerbird information from National Geographic:

Bowerbird stealing man-made objects video from National Geographic:

Satin bowerbird picture from Wikimedia commons is under a Creative Commons license.

Arkive photographs taken by:

© Tim Laman /

Nature Picture Library
5a Great George Street
United Kingdom
Tel: +44 (0) 117 911 4675
Fax: +44 (0) 117 911 4699

Arkive pictures may be reproduced for educational, scientific, or conservation purposes.


From Marlin to Marilyn: Clownfish Change Their Genders! Bizarre Courtship and Mating Rituals in the Animal Kingdom


Clownfish in anemone home

It turns out Finding Nemo had it wrong.  When a barracuda ate mom in the first scene of the movie, Marlin would not become a single dad, because being a single dad clownfish is impossible.  Realistically, Marlin would have become Marilyn– a single mom!

Clownfish are protandrous sequential hermaphrodites.  In other more pronounceable words, clownfish start their lives as males and then change into females.  Why is this necessary?


Clownfish live in sea anemones and have adapted so they are unharmed by the anemone’s stings.  Because of its unique mutualistic relationship with the anemone (the clownfish eat parasites off the anemone, effectively cleaning it), the clownfish is reluctant to wander too far beyond its tentacly home.  This becomes problematic when the clownfish wants to meet members of the opposite sex, so the clownfish has evolved an interesting mechanism – sequential hermaphroditism – to overcome this obstacle.


Marlin and Dory from Finding Nemo movie

Instead of braving the dangerous open waters beyond the reef (no, neither Marlin nor Nemo would realistically breach the “drop-off” and make it back alive), all the clownfish living in one place are males except the oldest, which is always a female.  After the head female dies, the next-oldest male turns into a female!

I suppose Pixar would’ve had a hard time explaining why they turned Marlin into Marilyn after one scene – I would’ve been confused too.  But in reality, the animal world of romance hosts a plethora of bizarre courtship behaviors, mating rituals, and other such oddities that put human courtship to shame!


Clownfish picture 1 by ecatoncheires on Flickr:

Nemo picture: from Cthomasuscg on Flickr:

Interesting animal romance behaviors:

“Sequential hermaphroditism.”

Clownfish information at Shedd Aquarium:

Clownfish information at Visit Sea Life:

Clownfish information at Evolution Faq: