Birds all over the world use the same sound to warn of threats

nature & planetanalysisThe Conversation: Arts + Culture (US)

Birds all over the world use the same sound to warn of threats

the gist

More than 20 bird species on several continents make the same alarm call when they see a brood parasite such as a cuckoo. Species that share this call live in areas with more brood parasites, and birds in Australia respond to calls recorded in China and vice versa. Birds that have never seen a cuckoo do not make the call, but learn to produce it by hearing others. This means the response is instinctive while the call itself is learned, a midpoint that Darwin had proposed as a possible stepping stone toward language.

how it works

Brood parasites lay eggs in other birds' nests, and the host parents raise the chick, which can push the host's own young out. Hearing a specific alarm call from neighbouring birds helps other species respond quickly and mob the cuckoo. Because the call is learned by imitation after exposure to cuckoos, it can spread between individuals and species.

so what

It is one of the first clear examples of an animal sound that combines instinctive and learned components, offering a concrete case of how language-like communication might have begun. It also shows that unrelated species can share a 'word' for a common threat.

the bigger pattern

Darwin proposed in the 19th century that instinctive cries used in new contexts could be a step toward language. Learned signals that are tied to specific threats are also found in primates, such as the distinct alarm calls of vervet monkeys.

Hampi was once one of the world's largest cities, until its Vijayanagara capital was destroyed in 1565

the gist

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.

how it works

The city was built around a fortified core with temples, markets and water structures along the river, supplied by an extensive network of roads and waterworks. When the empire fell, the city was not rebuilt, so its stone monuments were left standing.

so what

Hampi shows how quickly a great city can vanish after a military defeat, and how a ruined capital can remain sacred. Its ruins give historians a view of medieval South Asia that few other sites can match.

fun fact

The name Hampi comes from Pampa, an old name for the Tungabhadra River.

From Wikipedia, the free encyclopedia · text CC BY-SA 4.0

Image: Wikimedia Commons

source: Wikipedia ↗

2 min

politicsshortCNA2:01

False allegations about Singapore’s hand in Indonesia’s markets and a made-up meeting

from CNA

CNA Verify has found close to 400 posts pushing falsehoods tying Singapore to Indonesia’s stock market rout and to a secret meeting that never took place. Together, they drew nearly 12 million views, and some were circulated by accounts that appeared to be working in concert, across multiple social media platforms.

Here’s how the disinformation campaign targeting Singapore was uncovered.

on YouTube: CNA ↗