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Waterholes visited by the endangered Gouldian finch contained trace DNA that allowed scientists to detect the bird’s presence.Credit: photographereddie/Getty

For the first time, researchers have detected an endangered bird in the wild using traces of the genetic material it left behind. Environmental DNA gathered from waterholes in northern Australia revealed that Gouldian finches (Erythrura gouldiae) had visited the site in the previous two days. (Rangers also confirmed the species’ presence at the locations.) Compared with conventional methods that involve capturing or tracking, the technique is often safer for both animals and researchers, cheaper and, in some cases, more accurate and sensitive. But some scientists say environmental DNA is too easily tainted to be fully relied on.

Nature | 6 min read

Reference: Endangered Species Research paper

Hong Kong protests close universities

Classes have been cancelled and research disrupted in the wake of violent clashes between police and protesters on the campuses of leading Hong Kong universities. Hong Kong Polytechnic University, City University of Hong Kong and the Chinese University of Hong Kong are the latest battlegrounds for protests that hinge on the extent of the territory’s independence from the mainland.

Nature | 4 min read

The Australian government has released new guidelines for universities to protect themselves against foreign interference. The move comes amid concerns over China’s influence on Australian campuses, and after major cybersecurity breaches at the Australian National University in Canberra. The guidelines require institutions to do due diligence on research collaborations with foreign partners and to introduce robust cybersafety strategies.

Nature | 2 mins

Features & opinion

A handful of European institutions that have been hit by scandal are hiring integrity inspectors to vet researchers’ papers before they go to journals. Perhaps surprisingly, their researchers see the extra layer of checks as protective, not intrusive. “Because of the manuscript check, I sleep at night,” says biologist Björn von Eyss.

Nature | 11 min read

Base editors are a new class of CRISPR-based tools that excel at correcting single-site mutations. They are proteins that chemically change one DNA base to another without completely breaking the DNA backbone, making them more efficient and less error-prone than CRISPR–Cas9. Researchers hope that base editors might one day be used to treat human genetic diseases — if they can overcome important hurdles.

Nature | 11 min read

Considering how widespread same-sex sexual behaviour (SSB) is in animals across species and clades, it’s time to rethink some biased assumptions about its evolutionary origins and benefits, argue five biologists. “We aim to redefine the null hypothesis in studies of SSB,” they write. “Put simply, we are proposing a shift from asking ‘Why engage in SSB?’ to ‘Why not?’

Nature Ecology & Evolution | 31 min read

By the numbers More than 1,500 The number of animal species in which same-sex sexual behaviour has been recorded, with a widespread distribution across most major clades.

Image of the week

Credit: Paul Goldstein/Cover Images

A young jaguar (Panthera onca) in the Pantanal wetlands region in Brazil was spotted playing with a discarded plastic bottle by wildlife photographer Paul Goldstein, who described the sight as ‘distressing’. He added that the animal was probably attracted by the scent of the bottle, which would have floated downstream during the wet season.

See more of the month’s most compelling science images, selected by Nature’s photo team.