Could number of Swiftlets entering the Entrance Hole before dark justify the number of nest inside the farm? This is another question posted to me by my reader.
Well yes but to a certain extent. Thru my experiences, I would suggest for every 1 nest in the farm they would be approximately 8-10 birds.
Some may argue that for every 1 nest there would be 2 birds. Obviously we know that it needs 2 birds to build 1 nest. Bear in mind birds may stay in farm but they may not build nest instantly. Some might be young birds that are not mature enough to build nests while others may be too old to build one. Some may just stay for couple of weeks and leave later.
I had seen and witnessed it myself farms of having plenty of birds playing and staying but the low number of nests inside the farm surprised me.
There is one noticeable farm in Johor that I had visited not too long ago. The owner cried that all his friend congratulate him for having a successful farm as everyday they see few hundred of bird entering his farm at dusk.
His farm has the most birds compared to other farms around that area. It was a 3 year old farm. While visiting the farm there were less than 20 nests inside. This really happens of cos this is due to some problems in the farm.
So number of birds entering farm at dusk may sometimes fool us. Nevertheless the 1 nest to every 8-10 birds would be still a good guideline for estimating the number of nests without entering farms. Different people may suggest differently but this is my opinion.
Good farming ALL!