Birds and monkeys in the Amazon share information via ‘internet of the forest’: new research

Ettore Camerlenghi, Deakin University and Ari Martínez, University of California, Santa Cruz

You might go for a walk in the forest to disconnect from work and calm your nerves after a busy week. The chirping and calls of birds in the canopy above might be exactly what allows you to relax.

But what sounds soothing to humans may signal danger to other animals – and trigger fear across the forest.

In our research, published today in Current Biology, we show that when some animals spot a predator they issue a warning cry that is picked up by others and spread through the rainforest canopy. For a time, different species are linked into a shared information network, and parts of the forest briefly fall silent.

Birds and monkeys

During an expedition to a remote area of the Peruvian Amazon, working with a falconer, we used trained raptors to trigger warning calls from birds and primates. We recorded the calls then played them back into the forest and monitored how the community responded.

We already knew that birds sometimes repeat the warnings of others – occasionally even those of different species, or of primates. What we wanted to know was how widespread this behaviour is across the animal community.

Researchers released birds of prey in the Amazon rainforest to study how the alarm calls of other animals travel through the ‘internet of the forest’.

We discovered that alarm calls produced by small bird species – those weighing less than 100 grams – were most often passed on. Other small birds living in the canopy were the most likely to relay the call, but other animals joined in too.

Larger species, including capuchin and spider monkeys, sometimes responded as well. Two canopy species in particular – the black-fronted and the white-fronted nunbirds – stood out as especially likely to repeat and propagate the warnings of their neighbours throughout the forest.

Sounds and silence

Alarm calls from species living in the forest understorey were far less likely to spread and be propagated by other birds or primates.

However, even when these alarm calls were not repeated, they changed the forest’s soundscape. Small canopy birds almost completely stopped singing after hearing a predator alert. At the same time, animals in lower forest layers often continued to make sounds despite the perceived threat.

Together, these findings suggest that the Amazonian canopy is not only the rainforest’s most mysterious layer – largely unexplored and home to much of its biodiversity – but also functions as an information highway, like a fibre-optic network through which animals rapidly share signals of danger.

A new layer of the ‘internet of the forest’

In the past decade, the idea of an “internet of the forest” has become popular through the concept of the “wood wide web”, where plants exchange resources and information via root systems and fungal networks. Our work points to another communication system, one operating high above the ground.

Suspended above our heads is a vast ecosystem where animals constantly listen to one another, forming an eavesdropping network that spreads critical information within seconds.

The vocal activity of birds is usually associated with finding mates and defending territories. However, we now know that sometimes this activity, or lack of it, may represent pulses of a soundscape of fear.

Next time you walk through a rainforest, look up and listen to the birds. A sudden silence may mean a raptor is gliding somewhere above the canopy.

Ettore Camerlenghi, Associate Research Fellow, Avian Behaviour, Deakin University and Ari Martínez, Assistant Professor of Ecology and Evolutionary Biology, University of California, Santa Cruz

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→April 21, 2026

How birds are spreading plastic pollution

White storks and gulls feeding at a landfill. Enrique García Muñoz (FotoConCiencia), CC BY-NC-ND

Andy J. Green, Estación Biológica de Doñana (EBD-CSIC); Manchester Metropolitan University

Hungry gulls do not only steal our chips and sandwiches. They learn our habits, and look for reliable sources of food. That includes waste treatment centres, landfill or anywhere food waste is concentrated. Many gull populations have moved inland from the coast to exploit these sources of food.

Wherever our waste is processed, gulls and other birds can forage. At landfills, gulls feed on waste before it is covered up. If there are plastic or glass pieces covered in food that are small enough, gulls will swallow them whole. Only the food itself gets digested, and when the gull flies back to its roost site, the waste gets regurgitated, polluting that site. This movement of pollutants is known as “biovectoring”.

For the first time, scientists like me are now quantifying just how much plastic and other waste is being leaked into important nature areas through the daily movements of birds.

Many lesser black-backed gulls breeding in the UK and other parts of northern Europe migrate to Andalusia in southern Spain, where they form a wintering population of over 100,000 feeding mainly in rice fields and landfills. Fortunately, many of these birds are fitted with GPS tags while breeding. This enables detailed tracking of their movements.

Fuente de Piedra lake in Málaga is a hotspot for migrating lesser black-backed gulls. This wetland has such special natural significance, it’s designated as an internationally important site under a global convention known as Ramsar. It’s most famous for the largest breeding colony of flamingos in Spain. Gulls fly up to 50 miles to landfills to feed, then fly back to roost.

By combining GPS data with waterbird counts, and analyses of regurgitated pellets, scientists have estimated that an average of 400kg of plastics, plus more than two tonnes of other debris such as glass, textiles or ceramics, are deposited by this gull species into the lake each year. This lake has no outflow, making it salty and hence flamingo friendly. Those imported plastics remain in the lake, breaking down into microplastics. They can be ingested by flamingo chicks, aquatic insects and other animals.

Two yellow-legged gulls chase a white stork that is carrying plastic in its bill, which it picked up at a landfill. Enrique García Muñoz (FotoConCiencia), CC BY-NC-ND

In coastal Andalusia, these gulls join the resident yellow-legged gulls (equivalent to our herring gulls) and a mixture of migratory and resident white storks as the three major waterbird visitors to landfills.

In the Cádiz Bay wetlands (another Ramsar site), surrounding the historical city that is now a favourite stop for cruise ships, the three species combine to spread different types and sizes of plastics into different microhabitats. Annually, 530kg of plastics are deposited into wetlands via regurgitated pellets. Although a stork is bigger, so transports more waste per bird, most of the plastic is again moved by the lesser black-backed gulls that winter there in larger numbers.

Plastic film regurgitated by a gull roosting in a field in Atherton, Greater Manchester. Kane Brides, CC BY-NC-ND

This waste ingestion has strong effects on the birds themselves, through direct mortality from diseases, choking or becoming entangled with plastics, and toxic effects of the additives within them. Then after regurgitation in pellets, those plastics are a threat to all fauna and readily enter our food supply through aquaculture and table salt production, both important in Cádiz Bay.

These studies in Spain address a problem that is ongoing all over Europe. There are no comparable quantitative studies yet in the UK, but similar problems occur wherever gulls concentrate to feed on our waste. If white storks become abundant in the UK future, they will probably visit our landfills, together with gulls and perhaps cattle egrets.

The sealing of many landfills, and improvements in waste management may have contributed to recent declines in many gull populations in the UK and elsewhere. But these problems of plastic leakage will continue so long as our consumer society generates so much waste. Reducing waste, and reusing things is better than recycling, partly because food containers may get eaten by birds before they can be recycled. Cleaning our food containers before we bin them, and composting our own food waste, can also help to reduce this phenomenon.

Andy J. Green, Professor of Freshwater Ecology, Estación Biológica de Doñana (EBD-CSIC); Manchester Metropolitan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→March 28, 2026