http://www.scientificamerican.com/podcast/episode/gators-guard-birds-that-nest-nearby/
Florida’s Everglades are home to lots of large wading birds, like egrets and herons. But the ‘Glades also have lots of raccoons and possums. For the mammals, the birds’ nests are an all-you-can-eat buffet. And when an invasion occurs, “sometimes thousands of birds will abandon their nests, and just leave, and there’s littered remains of dead chicks and eggs that have been eaten.” Lucas Nell, an ecologist at the University of Georgia.
佛羅里達州的大沼澤地是許多大型涉禽(水鳥)的家鄉,像是白鷺、蒼鷺。沼澤也住著浣熊和負鼠。對於這些哺乳類,鳥巢就像吃到飽自助餐一樣。喬治亞州立大學生態學家,盧卡斯.尼歐表示「被入侵時,有時候上千隻鳥會遺棄牠們的巢,然後就離開,留下被吃掉的雛鳥和蛋的殘骸散落。」
Nell says that, in order to seek protection from their furry foes, birds actually prefer to build their nests in plots of swamp with a resident alligator. In fact, in one study a graduate student planted fake alligators. And the birds seemed to prefer to build nests close to them. “Where there’s a water source, there are alligators, so it’s sort of this moat of protection around these colonies.”
尼歐表示,為了尋求保護以躲避毛茸茸的敵人,鳥兒傾向於將鳥巢築於有短吻鱷居住的沼澤地。事實上,在一項研究中,一名研究生曾安插一些假的短吻鱷,而鳥兒似乎比較喜歡將巢築在靠近牠們的地方。「當有水資源的地方,就有短吻鱷,所以就類似於護城河保護著這些群體。」
Nell and his colleagues took to the Everglades at night, hunting for gators near and far from nests. “You have to use a spotlight and you see the little demon eyes shining out of the marsh.” They lassoed the gators, pulled them into the airboat, and took blood samples and body measurements.
尼歐和他同事於晚上搭船去大沼澤地,獵尋靠近和遠離鳥巢的鱷魚。「你必須用聚光燈,然後你會看到小小的惡魔般的眼睛在沼澤中閃爍。」他們將鱷魚套索後,拉上汽船,採取血液樣本並測量體長。
Turns out the gators near bird colonies were 13 percent fatter. Which means this unusual arrangement may be mutually beneficial. The birds get protection. And the alligators? They feast on any chicks that get kicked out of the nest, as well as on the rest of the extra-productive swamp life, fertilized by all that guano. The findings are in the journal PLoS ONE. [Lucas A. Nell et al, Presence of Breeding Birds Improves Body Condition for a Crocodilian Nest Protector]
結果發現靠近鳥群的鱷魚較遠離的胖了百分之十三。這表示此種不尋常的安排可能皆有利於雙方。鳥兒受到保護,那鱷魚呢?牠們享用被踢出巢的雛鳥,還有其餘被鳥糞滋養以至於特別多產的沼澤生命。這項發現收錄於PLos ONE期刊(為一份同行評審的開放獲取科學期刊,由公共科學圖書館(Public Library of Science,PLOS)自2006年發行。PLOS ONE為全世界文章刊載數量最多的期刊。所刊載的文章包含科學及醫學各領域的基礎研究)。
There is one drawback for adult birds who stray too close to their bodyguard: Gators are not discriminating diners. “I liken it less to a bodyguard situation, more like keeping some psychopathic murderer in your yard, to keep out cat burglars.”
當成鳥誤走而太靠近牠們的保全時有一個缺點:鱷魚並非有識別能力的用餐者。「將鱷魚比作一個在你家院子,用來趕走身手矯捷的盜賊的神經病殺手,較保全貼切些。」
—Christopher Intagliata