It’s the sort a sneaky trick only a gull would learn: by watching how people handle their food, the birds can work out when there are snacks to be had. Researchers found that herring gulls were more likely to peck at items left on the ground if humans had pretended to eat them first.

這種偷偷摸摸的技倆只有海鷗才學得起來：藉由觀察人類如何處理食物，海鷗能夠算出什麼時候會有點心可以吃。研究人員近日發現，黑脊鷗比較有可能會去啄食人類假裝先吃過、再留在地上的東西。

The study suggests that gulls take cues from human behavior to help them home in on tasty scraps in the rubbish people leave behind. “People don’t tend to think of wild animals as using cues from humans like this,” said Madeleine Goumas, a researcher at the University of Exeter. “It’s the kind of behavior that’s more often associated with domesticated animals or those kept in captivity.”

該研究指出，海鷗會從人類行為得到提示，幫助它們在人類留下的垃圾裡面精準定位出美味的食物碎屑。英國艾希特大學的研究人員瑪德蓮‧郭瑪斯指出：「人們通常不太會想到野生動物能像這樣運用來自人類的提示。」她表示：「這類行為比較常讓人聯想到被馴化、或是那些被關起來豢養的動物。」

Goumas, who has become one of the more prominent gull researchers in Britain, reported last year that maintaining eye contact can deter seagulls from snatching food. In tests with bags of chips in seaside towns, she found that staring the birds out put them off their daring raids.

郭瑪斯近來成為英國頗富盛名的海鷗研究學者，她在去年的研究報告中指出，跟海鷗保持眼神接觸可以威懾它們不敢從人類手中搶走食物。她當時在靠海的城鎮用炸薯條進行實驗，發現瞪視海鷗可以有效遏止它們放肆的掠奪行徑。

To follow up that work, Goumas wanted to see whether gulls pick up on subtle human cues to help them find their next meal. And so she set off to the Cornish towns of Falmouth, St Ives, Newquay and Penzance, and Plymouth in Devon, armed with shop-bought flapjacks in shiny blue wrappers, a supply of blue sponges, and a pair of dark glasses.

為了進行進一步研究，郭瑪斯想知道海鷗是否能接收細微的人類行為暗示，來幫助它們找到下一餐。於是，她動身前往康瓦爾郡的幾個城鎮，包括法爾茅斯、聖艾夫斯、紐基和彭贊斯，以及德文郡的普利茅斯。她身上配備了從商店買來、裝在閃亮藍色包裝裡的烤燕麥棒、一批藍色海綿，還有一副墨鏡。

For the first experiment, Goumas donned the sunglasses and walked toward her chosen bird, carrying a bucket with a flapjack in each hand. When she was about 8m from the gull, she sat down, flipped the buckets over so they concealed the snacks, and pushed them out to her sides. She then lifted off the buckets, picked up one of the flapjacks, stood up and pretended to eat it. After 20 seconds, she put the flapjack back and retreated a safe distance.

在第一項實驗中，郭瑪斯戴上墨鏡，走向她選定的海鷗，兩手各拎著一個水桶和一包烤燕麥棒。當她接近到距離海鷗約八公尺時，便坐了下來，把水桶翻過去藏起點心，然後將它們推向身旁兩側。接下來，她把水桶翻開，選了一包燕麥棒，站起來假裝在吃。這項行為進行二十秒後，她再把燕麥棒放回水桶底下，撤退到安全的距離外。

Goumas, who wore the sunglasses to avoid deterring the birds with her gaze, recorded what the gulls did next. Out of 38 birds singled out for tests, 24 approached and pecked at the flapjacks. Of these, 19 — or 74 percent — pecked at the flapjack she had recently handled. The results suggest that the birds paid attention when she pretended to eat the snack.

郭瑪斯戴著墨鏡是為了避免海鷗被她的目光嚇到不敢來吃，隨後她記錄了海鷗們接下來的行動。在選出來作為測驗對象的三十八隻海鷗中，有二十四隻接近並啄食燕麥棒。而在這些吃到點心的海鷗裡面，有十九隻──也就是百分之七十四──啄的是郭瑪斯剛剛碰過的包裝。結果顯示，當她假裝在吃點心時，這些鳥確實有在注意。

To see whether the effect held true for other items, Goumas set off to different parts of the towns in search of more gulls. Once in place, she performed the same experiment but substituted the flapjacks for little blue sponges. This time, the gulls pecked both the handled and unhandled items roughly equally. “Seagulls have made an association between humans and food and the reason for that is probably that we’re not disposing of our food properly when we’ve finished it,” Goumas said. Details of the work are published in Royal Society Open Science.

為了確定這項結果是否在其他物品上也能成立，郭瑪斯遂前往城鎮的不同地點尋找更多海鷗。只要抵達一個地點，她就會進行一樣的實驗，但是把燕麥棒掉包，換成小的藍色海綿。這次，她碰過和沒碰過的物品，海鷗兩者都啄，且比例大約相同。郭瑪斯表示：「海鷗已經產生人類和食物之間的聯想，其原因大概是因為我們吃完東西以後都沒有好好處理垃圾。」關於該研究的細節日前發表於《皇家學會開放科學》期刊。

Clashes between humans and herring gulls are believed to be on the rise as urban expansion encroaches on and overwhelms the birds’ traditional nesting grounds. While the birds seem abundant in seaside towns, the population in Britain fell 60 percent between 1969 and 2015, putting the birds on the UK’s red list of Birds of Conservation Concern.

科學家相信，隨著都市擴張侵占並吞沒這種鳥類的傳統築巢地點，人類和黑脊鷗之間的衝突正在逐漸升溫。儘管這種鳥類在靠海城鎮看起來數量很多，英國的黑脊鷗族群卻在一九六九年到二○一五年間減少了百分之六十，使得它們被列入英國「須關注保育鳥類」的紅色清單中。

“Whereas a lot of animals may not be able to live alongside humans and make use of urban environments, herring gulls seem to have been able to adapt and this is possibly one way they have become successful,” Goumas said. “Most seagulls don’t snatch food from people, they wait. If we don’t want to have gulls coming up to us and trying to get our food, we need to dispose of our food properly, and have bins that actually keep food inside them,” she added.

郭瑪斯表示：「相對於許多動物可能無法在人類週遭生活，也無法利用都市環境，黑脊鷗看起來已經能夠適應與人類生活，而這也可能是它們成功繁衍的方式之一。」她補充說：「大部份的海鷗不會從人類手上搶走食物，它們只是在旁邊等。如果我們以後不想看到海鷗朝我們正面飛來，企圖得到食物，那人類就必須正確地丟棄食物，並且設置真正能夠存放廢棄食物（而不會被海鷗打開）的垃圾桶。」

Source article: https://www.taipeitimes.com/News/lang/archives/2020/03/08/2003732262