Here are some more of the weaver birds I mentioned before.  There are 16 to 20 weaver species and they all live in some sort of interesting communal nests.  The ones here are Lesser Masked Weavers.  They nest in large colonies with lots of hanging nests in the same tree.

 

The males build the nests all by themselves and it's wonderful to see.  They bring special grasses, often some distance, and start an arc which they hold together with their feet and then they pull the ends together and weave in a strand to hold it together forming a circle.  They fly back for each new blade of grass to weave in.  The bird on the right is holding a blade which he has clipped off with his bill at just the right length.  Ever try weaving with just your lips...........

It's hard to photo them because of the light sky behind them causing the silhouette effect. 

The males add to the nest making a ball and then an entrance which hangs down, making it difficult for predators to enter.

 

When they are finished it's sort of like an upside down gourd.  They can build one in less than a day.

 

Then they advertise the new 'house for rent to attractive female' by hanging upside down from the entrance by one foot and flapping their wings to attract females.  Apparently the females know that the best flappers also build the best nests and will produce good young too.

 

Here comes one now!  Dangle, dangle, flap, flap!

 

If she thinks his display is good enough, she will inspect the nest.  If she likes the nest, then, wonderful!   They will be a couple and move in.  If she doesn't, she may just ignore him and move on or she may tear it up!  Either way, the male will begin again and build a whole new one.  This seemed to be a happy couple--she went in and out several times and leave or shred anything.