Are you certain that birds or something else isn't stealing the green elderberries? Normally the birds don't go after my elderberries until they're ripe, but this past year was different.... I saw the full clusters of small green elderberries one day, and a few days later most of them were gone. Whatever ate them didn't seem to mind them being green.

No the dried flowers fall off but do not produce berries only 3 to 4 will form into berries from a cluster. I've spotted one cluster who produced a bit more berries as on this picture but still less that how it should.

My Mulberry trees and Elderberry shrubs · More Info

See how the flowers dried out and died, only 3 berries in that cluster. It's the first time all my 3 shrubs are blooming after 1 year since propagation. Is it too soon for them to produce berries because they're all recently blooming since 3 months?

Did you have plenty of pollinators like bees and insects at the time it was flowering?

I see a lot paper wasps, few butterflies everyday however very few bees. We're actually in summer, I see more butterflies and moths often in winter seasons than in summer here. Our winter is not too cold since no snow here.
It's been 3 months since they're starting to bloom for the first time, lots of elderflowers and they smell amazingly good. Could it be because it's too early to bear berries or lack of bees for pollination? Thank you.

If your shrub was old enough to flower, then it was able to set fruit. Assuming that your climate isn't a factor, you either didn't have sufficient pollinators (bees/insects) when needed, or you lacked a different cultivar for improved pollination. Perhaps your neighbor's elderberry is the same variety as whatever you cloned. I grow two different varieties of elderberry and have never experienced a lack of fruit being set.

Most Elderberry is self fruiting, the Elderberry which I've cloned is from my friend, she doesn't need other variety for cross pollination yet it is fruiting, she stays in a road next to me however she told me in winter she gets more berries than in summer also my neighbor's does not has an other variety shrub to cross pollinate.
I think I'll wait more until winter and see since it's the first time it's blooming, I'll try to buy bees from my local area in case it's a lack of pollination. Thank you.

In this article it says it takes 2 years, I don't know if it's concerning frosting season. https://homeguides.sfgate.com/long-elderberries-grow-74526.html

This doesn’t answer your question at all but I’m curious as to why you’re keen to grow elderberries in a tropical climate. You must have a fantastic choice of wonderful fruit available to you and elderberries, while ok for making a bit of jelly or syrup, are not much use otherwise. They’re horrible raw. They grow wild here and are pretty much disregarded as of much value in a garden. Is there a particular use you have for them in Mauritius?

Hi floral_uk, yes Elderberry is one of my dream plant mainly because of the nutritional or medicinal benefits of the elderberries. They do grow wild here only few districts, where it's colder and more rainy like where I am at Floreal.
We don't have too much variety, fruits are becoming drastically expensive, even 1 kg of apples will cost you around $7. Vegetables are becoming rare as well, it's a shame, since Covid, most of our food are becoming so expensive that we have to grow our own. I have to remove all my decorative plants and replace them with edibles. I'm very happy for my mulberries, however I just hope my Elderberry shrubs will fruit as well. This summer we have got less rain, I guess that could be the reason as well.