For decades, researchers have thought that access to food determined the brood size of birds. Now, biologists at Lund University in Sweden have discovered a completely new explanation: the body temperature of small birds can increase by more than 4°C to exceed 45°C when they are feeding their young. Larger broods would require more work, resulting in even higher body temperatures - something the birds would probably not survive.

New research identifying climate vulnerability hotspots has found that the number of people affected by multiple climate change risks could double if the global temperature rises by 2°C, compared to a rise of 1.5°C.

Ecologists have long known that agricultural and sewage pollution can cause low oxygen conditions and fish kills in rivers. A study published today in Nature Communications reports that hippo waste can have a similar effect in Africa’s Mara River, which passes through the world renowned Maasai Mara National Reserve of Kenya, home to more than 4,000 hippos.

With the arrival of spring, we look forward to the return of hundreds of species of migratory songbirds from their wintering grounds.

Looking at Earth from the International Space Station, astronauts see big, white clouds spreading across the planet. They cannot distinguish a gray rain cloud from a puffy white cloud. While satellites can see through many clouds and estimate the liquid precipitation they hold, they can’t see the smaller ice particles that create enormous rain clouds.

Two species of seal found in Antarctic seas are helping scientists collect data about the temperature and salinity of waters around vulnerable ice sheets in West Antarctica.

Orangutans, already critically endangered due to habitat loss from logging and large-scale farming, may face another threat in the form of smoke from natural and human-caused fires, a Rutgers University–New Brunswick study finds.

By studying streams on the UK coast, experts have calculated how much organic matter we might find on Mars, and where to look.

Onward! Our next order of business is to bid adieu to La Niña, as the sea surface temperature in the tropical Pacific returned to neutral conditions in April—that is, within 0.5°C of the long-term average.

Why was an earthquake in Virginia felt at more than twice the distance than a similar-sized earthquake in California? The answer is one that many people may not realize. Earthquakes east of the Rocky Mountains can cause noticeable ground shaking at much farther distances than comparably-sized earthquakes in the West.