It is rather difficult to differentiate between the two. Head nodding behavior were observed and carried out by both birds. You can also see the eye membrane of the bird on the left - it's certaintly not an eye defect.
They can be seen fetching nesting materials ranging from plastics, dry twigs, fresh lalang leaves and dry grasses. At printing time they were still busy fetching the materials.
The fetching time ranges from every 15 minutes to 30 minutes - usually occurs in the morning until late noon. Lesser or no nest building activities towards evening.
At times it can be really hot inside the roof. Although its hard to distinguish between the birds but i believed both of them did fetched some nesting materials.
Couple #1
A closer look at Couple # 1
Here you could clearly see the "tomium" feature located at its upper mandible palate.
Couple #2
A closer look at Couple # 2
Here is what i meant. They are almost identical. Note the color of the beak and roof of the beak on "Couple #1" bird. They look a bit more orangey on the beaks and has a darker ceiling on the upper side of the beak.
A sign of a new life has just started. This photo was taken on 9 March 2013 i.e. almost 1.5 mths after they were last seen fetching nesting materials into the roof. The food carried above looks like a piece of fish. I have seen them taking bread and a stick insect into the nest.
The evergreen Javan couple. Hope one day i could take their family photo.