On a cold morning in 2015, five-year-old Lucas stood on the bank of Blue Star River, hugging a dead salmon（鲑鱼）against his thick yellow coat. He looked up at his father, Steve, who nodded encouragingly. “Go ahead,” he said. “Put it in.” The young boy dragged his feet forward and held the fish as far as he could into the shallow water. “It’s floating!” Lucas yelled, delighted. For a moment, it’s almost as if the handsome salmon could come back to life.

Lucas’ salmon was just one of 100 or so dead bodies that will land in Blue Star River in a half-hour activity this morning, delivered by dozens of volunteers. None of the salmon will rise from the dead, but Andy, president of the Fish Rescue Society, who has promoted this gathering, is carrying out the resurrection （复活）project of salmon.

Andy led the group’s campaign to recover this urban waterway’s salmon population. “The Fish Rescue Society started exploring the possibility of recovering the salmon in the river in the mid-1990s, and they also focused on river recovery in cities worldwide.”

Andy and his group are devoted to giving the river a full make-over. This monumental repair job, supported by approximately $95,000 of funding from the Pacific Salmon Foundation over the past 15 years, has involved recovering the river-habitat of salmon and preventing   it from wearing away. Work on the river’s final section was completed in October 2016.

People may use the expression “birdbrain” in English to talk about someone who is stupid, but crows prove that this is unfair. Now it has been discovered that crows may understand analogies.

It was once thought that only humans could understand analogies, which help us to solve problems creatively, put things into categories, and make scientific discoveries.

To test this ability in animals, scientists do “relational matching-to-sample”(RMTS) tests, according to the IFL Science website. If a pair was AA, for example, then picking BB to match it would be correct. If the pair was CD, however, then EF would be correct.

Apes and monkeys have learned RMTS, but scientists wanted to know if crows could do it, too. An international team led by Edward Wasserman from the University of Iowa in the US first trained two hooded crows to match things by color, shape, and number in what is called “identity matching-to-sample (IMTS)”, then moved onto RMTS.

For the IMTS test, the birds were put in a cage with a plastic tray that had three cards and two cups in it. The card in the middle was the sample card. The cups on either side were covered with the other two cards: One was the same as the sample (in the color, shape, or number of shapes pictured), while the other wasn’t. The cup with the card that matched the sample card contained two worms to eat.

In the second part of the experiment, the birds were tested with relational matching pairs. A card with two same-sized circles, for example, meant they should pick the test card with two same-sized squares and not two different-sized circles. The birds did well in the more difficult test and picked the correct card more than three quarters of the time, Science News reports.

Wasserman was surprised that crows were able to solve the problem without any training in RMTS. “What the crows have done is extraordinary,” he said in a news release. “Honestly, if it was only by force that the crows showed this learning, then it would have been an impressive result. But this was spontaneous.”

So perhaps it’s time to stop saying “birdbrain” permanently!

Feeding bread to the ducks is a fond pastime for many of us, reminding us of our happy childhood trips to the local park. But did you know that bread actually poses a danger to birds, as well as the environment? Eating it can cause our feathered friends to develop a condition called Angel Wing, which is when too much bread makes birds’ feathers grow too quickly. This additional weight puts a strain on their muscles, causing their wings to twist and drop open, and if not treated fast, they can lose the ability to fly.

“Angel Wing can be remedied if we reach birds before it has developed too severely,” says Caroline Simpson, a trustee of UK charity Swan Lifeline, which has rescued and treated more than 30,000 birds over the last 20 years. “Otherwise the consequence can be awful—such as amputations of the wing.” Adult swans can also develop gut and heart disease, so it’s important we do our bit to prevent this by feeding wild birds with the right kind of food.

Bread can also cause harmful changes to the natural ecosystem. Rotting bread at the bottom of rivers and lakes allows bacteria to breed, spreading disease and attracting rats and other vermin to our waterways. It can result in algal blooms and the presence of a mould called Aspergillus too, which has the potential to kill waterfowl and other wildlife if it gets into their lungs.

But this doesn’t mean we have to stop fun trips to feed the ducks. Giving birds the right food—like frozen peas, sweetcorn and lettuce leaves—is good for both them and the environment. So, next time you visit your local park, take a healthier alternative with you and do your bit to protect our precious wildlife.