“We had an opportunity to watch a pair of nesting Large Niltavas (Niltava grandis decipiens). We saw an odd behaviour by the adult male and would appreciate any opinions.
“The pair was cautious of our presence so we kept our distance. On one occasion the male came to ‘check us out’ (above). While we were watching it suddenly had an odd jerking movement and regurgitated a large blue object (Composite of 6 serial images below).
“There are two possibilities to explain this behaviour:
1. My wife, an astute bird watcher for >30 years, thinks the bird regurgitated a feed it was bringing to the young and then swallowed it back. I have seen many birds do this when their nest is watched to try and fool the observer into thinking the food is for themselves, not the young.
2. The other possibility is that the bird is regurgitating a pellet.
“There are problems with both possibilities.
“Regurgitated a feed: The item regurgitated looks like a blue-purple berry. But prey brought to young are generally insects and invertebrates. The adults will take berries but I have not seen any records of fruits given to young in the nest. I have seen a number of birds regurgitate feeds and so consider fruits still a possibility.
“Regurgitating a pellet: I have not seen any records of Large Niltavas regurgitating pellets. My personal belief is that most bird can regurgitate pellets and our knowledge is only limited by our observation. The jungle was too dense around the bird to go look for any pellet but my impression from watching was the item was swallowed back.
“Finally this could be a food bolus. Small insect items collected by aerial sallies kept in the crop where they form a ‘ball of insects called a bolus’. In that case it is not a not true regurgitation as the bolus is not mixed with digestive juices. (http://www.rspb.org.uk/makeahomeforwildlife/advice/expert/previous/regurgitate.aspx).
“I have limited knowledge of the alimentary tract of most birds and no specifics on the structure in the Large Niltava. Appreciate any sharing or articles/reports, experience or views.”
Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
25th March 2015
Location: 1500m ASL, Cameron Highlands, Malaysia
Habitat: Public road along primary montane forest