My memory of birds of Southeast Asia is dim, after 40 years this years, as we left Laos in 1975, after my first year of school.
So I don't remember a lot of birds, except to refresh my memory using books and, now, the Internet.
But I believe "PIV" is a member of the MUNIAS, which are very similar to the FINCHES, which in turn are very similar to the sparrows you see fluttering everywhere around your home, farms, streets, etc.
But, then, again, I think the "munias" beaks are a little bit too big to be the "piv" I remember as a small boy who followed uncles and cousins to the farm to catch, a few times.
The FINCHES beak seems to be the "piv" size beak that I remember....
http://www.ecologyasia.com/verts/birds/munias.htm
http://www.ecologyasia.com/verts/birds.htm
https://www.youtube.com/watch?v=FhaiP8Rpc-8
https://www.youtube.com/watch?v=5nCpo8pMnMc
https://www.youtube.com/watch?v=v4ulzgJB_Mg
This FINCH above here sounds a lot closer to the "piv" I remember in Laos. And so are the "weaver birds" of Indonesia, in one of the videos here, too...
https://www.youtube.com/watch?v=5nCpo8pMnMc
https://www.youtube.com/watch?v=_4UGvhbK1Is
https://www.youtube.com/watch?v=5nCpo8pMnMc
https://www.youtube.com/watch?v=VWRVvC5RXJk
https://www.youtube.com/watch?v=vH53lYeNqq8
https://www.youtube.com/watch?v=vH53lYeNqq8
https://www.youtube.com/watch?v=F1_PhFbJr2Q
The one above here are said to be "weaver birds" of Indonesia, in rice farms; and they make noises like the "piv" we knew about in Laos that would eat tons of rice.
But, obviously, this subspecies in Indonesia has an Indonesian-adaptation to it, so it looks slightly different in color from the brown-ish kind we have in Laos (or used to have). This subspecies, as you can see, has a "white" head (I assume those are the males)...
((((( In nature, most of the males are the fancier ones, as they have to be the absolutely most exquisite ... think of birds of paradise, hos huam, nraj, etc. where the females are very dull looking but the guys are incredibly beautiful... 'tis so the guys could mate with as many females as possible, whereas for the females, if you're protecting the eggs, you need to be as INCONSPICUOUS as possible, so you "blend in" with the surrounding so predators don't get to you, so you could nurture the next generation of your species, etc.))))
The two below videos are similar in beak; but they belong to the most numerous species, the "quelea" of Africa... But they are, as you can see here, also a plague where farmers are concerned in Africa, since they can devour whole farms, since they are so numerous in numbers...
The "piv" of Laos seem to fly in rather small groups, of a few to no more than 10 or 20, if I remember. Yes, when they converge to feed, there are dozens to hundreds, too; but I think that's because they converge, when they see a ripening farm of rice... But I think they disperse, after they feed, so each smaller group flies to nesting place of their own at night...
https://www.youtube.com/watch?v=PqLT8aKJuNQ
https://www.youtube.com/watch?v=Bw_RYF381R0
Each species, and each sub-species in turn, of course, adapt to a certain set of ecosystems and environments...
But they have similar beaks, with differential sizes and strength, to harvest the half a dozen or so fruits, nuts, seeds, and flies they need...
Anyway, this is why some people spend their whole lives watching and studying birds. Why they fly thousands of miles to see one or two exquistic "humming birds" down in Peru or Argentina or Brazil or Laos or Australia or New Papua, etc.
BTW, the most famous scientist since the 1800s is CHARLES DARWIN...
His exposition on the "NATURAL SELECTION" theory --- On the Origin of Species (On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life)--- had a large focus on FINCHES and similar birds, with strong beaks.... Ranging from very stubby to slimmer ones but you could see they are related because there's a similar shape to them, from one island in the Galapagos to another...