On Tuesday afternoon, Mr. Barrett, 54, returned to the Pond to check on the Mandarin duck. Carrying binoculars, Mr. Barrett, who works as an investor and computer scientist when he’s not birding, circled the shore trying to spot the glamorous creature. 
 
 After many minutes of fruitless searching, he spotted the duck nestled near a rock across the Pond, on the eastern shore of the Hallett Nature Sanctuary. 
 
 Joined by a fellow birder on a lunch break from her day job, Mr. Barrett began to strategize how he’d coax the duck from the other side, which was thick with trees and shadows in the late afternoon. “We need to be enterprising,” he said. 
 
 First, the pair of birders tried to entice him. Mr. Barrett purchased a salted soft pretzel from a cart in the park, ripping off tiny pieces and tossing them off the shore. No luck. 
 
 The second birder, Sandra Critelli, muttered that she needed to get back to the office soon. “But that damn duck!” she said. 
 
 As his next option, Mr. Barrett tried to chase the duck away from its nook on the distant side of the Pond. After walking around the Pond to the forested nature sanctuary, Mr. Barrett climbed around trees and over branches to reach the shore. Then, he began to quack. 
 
 Yes, quack. And soon, a small group of ducks began to swim out of the shadows. 
 
 Mr. Barrett sprinted over the bridge and back to the other side of the Pond. By the time he got there, the Mandarin duck was already basking in the sun with his mallard friends, posing for awe-struck onlookers with cameras. ||||| Image copyright Silviu Petrovan/Mihai Leu Image caption A mallard duck closes in on a fledgling black redstart 
 
 Wild mallard ducks have been observed attacking and eating migratory birds. 
 
 This has never been documented before and is probably a new behaviour, say scientists. 
 
 Zoologists at the University of Cambridge filmed a group of mallard ducks hunting other birds on a reservoir in Romania. 
 
 Two fledglings - a grey wagtail and a black redstart - were chased and swallowed when they landed in the water. 
 
 Mallards are one of the most abundant types of wild duck, and a common sight in parks and on lakes. 
 
 The duck normally snacks on seeds, acorns, berries, plants and insects. 
 
 It has, on occasions, been seen to eat small fish, but bigger vertebrates are normally strictly off the menu. 
 
 Image copyright Silviu Petrovan/Mihai Leu Image caption The black redstart is captured 
 
 Dr Silviu Petrovan noticed the unusual behaviour of a group of mallards while he was out bird watching with friends near a national park in southwest Romania. 
 
 He saw the adult female duck grab the grey wagtail in her beak, and repeatedly submerge it in the water, before eventually eating it. 
 
 A second bird - a fledgling black redstart - then landed in the water, where it was chased by juvenile mallard ducks. 
 
 "The poor bird landed on the water and was screaming and trying to navigate itself out of danger," said Dr Petrovan. "Then it was almost instantaneously attacked by the mallards." 
 
 The bird eventually disappeared - assumed to be drowned or consumed. 
 
 The scientists could find no record of mallard bird predation in the scientific literature, which suggests such behaviour is both "very rare" and newly-learned. 
 
 "The mallard was massively struggling to eat that wagtail, presumably because it couldn't actually tear it to pieces because the bill is flattened - it's not designed for ripping prey apart," said Dr Petrovan. 
 
 "Digesting bones and feathers - that's not something that mallards have really evolved to do." 
 
 Image copyright Silviu Petrovan/Mihai Leu Image caption The unfortunate grey wagtail is swallowed almost whole 
 
 Ducks by nature are seldom aggressive and tend not to enjoy novel food. 
 
 However, mallards in California have been seen to enter the sea to feed on sand crabs, perhaps to find new sources of high-energy protein. 
 
 The same may be happening at the reservoir, which is largely deep-water. 
 
 "Potentially there is quite a lot of pressure for those fast-growing juveniles to get animal protein intake, and therefore they are looking at opportunities to supplement that," said Dr Petrovan. 
 
 "But, the fact that these individuals seem to have learnt how to hunt birds is pretty extraordinary." 
 
 The findings are published in the journal, Waterbirds. 
 
 Follow Helen on Twitter.
– If there's anywhere you'll see a punk rocker with a "multicolored mohawk," New York City would be the place. But the Mandarin duck that's been hanging out in Central Park since mid-October is another story entirely. The New York Times reports the creature with brilliantly hued plumage was first spotted Oct. 10 and has since gone viral, with spectators all vying for pictures of an animal usually seen only in East Asia. For now, the duck's origins remain a mystery: None of the city's zoos have this type of duck missing from the roster, and it's illegal in NYC to keep a duck as a pet. That means the duck perhaps escaped from, say, an owner in New Jersey and made its way to the city, or maybe the owner itself got sick of the duck and unceremoniously left it and ran. Either way, the duck has been a huge hit. "It's just an incredible gift to New York," one birder tells CBS New York. Avian experts believe that based on its feeding habits—it likes bugs and vegetation skimmed from the water's surface—the duck should be able to survive just fine in the Big Apple, and park officials say they're just going to let it be unless it becomes injured. It already appears to have made friends with the park's mallards. Read more on how a pair of eager birders tried (and ultimately succeeded) to coax the duck to come closer for pictures, including with a hot pretzel from a nearby cart and, yes, quacking. (The search for a pink-headed duck in Myanmar.)