Hello and welcome to the Intelligence on Economist Radio. I'm your host, Jason Palmer. Every weekday, we provide a fresh perspective on the events shaping your world.

World Rugby, the governing body for international rugby union, has made what may be a momentous decision,

banning trans women from the women's game.

We look into the science that informed their decision and into the heated discussion around it.

And, for all but the most attentive, bird song is lost in the bustle of life.

Now, a London musician has composed an album built entirely around the tunes of endangered birds,

turning ears towards a soundscape that's slowly disappearing.

First up, though. On Saturday, Taiwan enjoyed its National Day celebrations.

President Sai Ying Wen gave a speech to mark the occasion.

If we can officially President Sai Ying-Wan gave a speech to mark the occasion.

She called for the de-escalation of tensions with mainland China,

asking Beijing to jointly facilitate cross-strait reconciliation and peaceful dialogue. But Beijing dismissed the message, and just a few hours later,

released a video threatening military invasion.

It was just the latest bit of propaganda ramping up China's claim over Taiwan.

Last month, the army released a video depicting an attack on American

forces in Guam. The message was clear. Don't defend Taiwan in what would swiftly become a messy

regional war. What we're seeing in the last few months is a level of military activity, a level of muscle flexing by China around Taiwan that is unprecedented in 20 years.

Shashonk Joshi is the economist's defense editor.

We have seen aerial exercises, naval exercises on all sides of the island,

and some of that is in response to American efforts to bolster their own ties to Taiwan.

In the past several months, we have seen very senior U.S. officials visit Taiwan in ways that would probably have

been considered provocative, even reckless, if that had happened several years ago.

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