火烈鸟奇观

我有幸走进广袤的非洲草原，与一团、更准确地说是一大片温和燃烧的烈火――大火烈鸟进行了亲密接触，探索到这群有着火红羽毛的大鸟不为人知的秘密。

那是肯尼亚西部，著名的东非大裂谷贯穿其中。在那深壑万丈、险景不绝的峡谷中，隐藏着一潭潋滟的湖水，这就是纳古鲁湖。纳古鲁湖不大，只有62平方公里，水也很浅，只有两三米深。然而令人惊奇的是，这里竟聚集有300万只大火烈鸟，是世界上最大的大火烈鸟聚居地，被称为“大火烈鸟的天堂”。

第一次见到大火烈鸟，我就被极大地震惊了。这种喜欢扎堆生活的大鸟，往往成千上万只甚至多达10万只聚集在一起，与雁类相似的叫声此起彼伏，震耳欲聋。远远望去，红腿如林，一条条长颈频频交替蠕动，十分壮观。如果从飞机上向下看，遍地通红，绵延好几公里，就像一块巨大的红地毯，又宛如一片在泥沼原野上沸腾的红色波涛，一派生机勃勃的景象，令人心旷神怡。

大火烈鸟又称红鹳、红鹤、火鹤等，雄雌相似，是一种羽色鲜艳、多姿多彩的大型涉禽，体长130－142厘米。全身的羽毛主要为朱红色，特别是翅膀基部的羽毛，光泽闪亮，远远看去就像一团熊熊燃烧的烈火，因此得名。它的体形长得很奇特，身体纤细，头部很小，镰刀形的嘴细长弯曲向下，前端为黑色，中间为淡红色，基部为黄色。黄色的眼睛很小，与庞大的身躯相比显得很不协调。细长的颈部弯曲呈“S”形，双翼展开达160厘米以上，尾羽却很短。

大火烈鸟羽毛鲜艳的颜色非常引人注目，特别是一大群大火烈鸟一起飞翔时，其场景蔚为壮观。这种鲜艳的红色并非是一种伪装，而是与这种鸟类所摄取的食物有很大的关系。

大火烈鸟一般以贝类为食，贝类含有大量色素，比如类胡萝卜素。对于各种贝壳类、软体类动物或者蠕虫来说，类胡萝卜素与它们体内的蛋白质合成有着非常重要的联系。此外，一只大火烈鸟每天还要吃掉大量的螺旋藻，而螺旋藻中除含有大量蛋白质外，还含有一种特殊的叶红素。当大火烈鸟吞食这些食物后，这些色素就存在鸟的体内，特别是在羽毛中积存起来，这就是为什么大火烈鸟的羽毛如火焰般鲜红的原因。

火烈鸟的性情温和，平时显得胆怯而机警，游泳的技术也很出色。飞翔时，能把颈部和两脚伸长呈一条直线，而且只要有一只飞上天空，就会有一大群紧紧跟随，边飞边鸣，就像一条红色的彩练从蓝天白云中掠过。

大火烈鸟的繁殖是集团式的，成百上千只在一起组成一个求偶群，但婚配却主要是“一夫一妻”制。如果没有一定数量的种群“刺激”，大火烈鸟甚至会发生只恋爱不产子的现象。交尾时雄鸟跳到雌鸟的身上，只有这时才能清楚地分辨它们的性别。

每年营巢一次，但新巢大多搭建在旧巢之上。巢高出水面，一般多选择在三面环水的半岛形土墩或泥滩上，有时也在水中用杂草建筑一个“小岛”。筑巢时，大火烈鸟用喙把潮湿的泥巴滚成小球，再混入一些草茎等纤维性物质，然后用脚一层层砌成上小下大、顶部为凹槽的“碉堡”式的巢，别具一格，坚固耐用，任凭大雨冲刷也不会倒塌。它的卵呈淡白色，每窝仅产l~2枚。孵卵工作由雄鸟和雌鸟共同担任，一只孵化时，另一只就守卫在巢的旁边。雏鸟出壳后羽毛一干，马上就能下地行走，第二天即可下水游泳，4~5天后就十分活跃了，但主要还是依靠吃“父母”嗉囊里分泌的乳状物来生存。雏鸟的绒羽呈灰色丝状，腿也是灰色的，更有趣的是，嘴并不弯曲，而是直的。到了两个半月的时候，幼鸟已经学会飞翔，一年以后体形几乎同成鸟一样大了，但体色仍然是灰色的，直到第三年才能变为红色，达到性成熟。大火烈鸟的寿命为20~50年。

非洲的纳古鲁湖被称为“大火烈鸟的天堂”。这里每年最多的时候集结有300多万只火烈鸟。每天，湖水之上总是浮动着一条条红色的彩练，如落英逐逝水，似朝霞映碧池，给雄险的大裂谷平添了几分优柔妩媚的韵致。它们身披白中透红的粉红色羽衣，两条长腿悠然挺立，远远望去，周身红得就像一团烈火，两腿则红得就像炽燃的两根火柱。一旦成千上万只大火烈鸟集聚在一起，一池湖水顿时被映照得通体红透。纳古鲁湖的大火烈鸟群，历来被称为世界上“火光永不熄灭” 的一大奇观。

大火烈鸟经常在湖的浅水区游窜，在岸畔信步徜徉，交颈嬉戏。一时兴起，扑棱棱双翅舒展，长颈猛摇，列成严整的方阵，翩然起舞。每当此时，湖光鸟影，交相辉映，犹如万树桃花在水中飘游。忽然它们又嘎啦啦一声长鸣，倏然腾空，排成整齐的队伍绕着湖边翻飞，此时一湖桃花遂化为一片彩霞，直烧中天。这一奇幻的景色被誉为“世界禽鸟王国中的绝景”。为观赏这一绝景，每年有十几万游客从世界各地来到纳古鲁湖。

（本文摄影 夏富祥 吴常云）

A Spectacle of Flamingos

By Li Xiangtao

I consider myself lucky for visiting the world’s largest colony of greater flamingoes in Africa. To be lyrical, what I witnessed was an expansion of blazing flames.

Hidden in the west Kenya where the Great Rift Valley cuts down into the Earth and zigzags, the 62-square-kilometer Lake Nakuru is 2-3 meters in depth. The paradise-like lake is home to about 4 million greater flamingos.

The first time I faced the huge flocks of the pink wading birds, I was totally amazed. The red legs resembled a huge forest and the slender necks moved in a fascinating way. They made deafening noises.

Their plumage looked impressively pretty. I learned that the red is not a disguise the birds adopt for self protection. It comes from the food on which they feed: shellfish in the lake that contains a large quantity of coloring matters such as carotene, and spirulina that contains erythrophyll, which is also red.

Greater flamingos are mild creatures. The shy birds are always on alert against possible dangers. They are good swimmers. In flight, they stretch their legs and neck in one straight line. When one flamingo takes wings and soars into the sky, others will follow suit immediately, forming a vermilion belt against the azure sky.

Though they gather together in large flocks of hundreds or even thousands while mating, flamingos are “monogamists”. Their genders can be distinguished only by the time they are in the process of mating. Those on the top are male.

Greater flamingos build their nests once a year. Most new nests are erected on the old ones. Usually these nests rest on some peninsular mounds above water. Some nests are in the water protected by plants and mud. These nests look like blockhouses, sturdy and well-built against storms. The mates take turns incubating one or two eggs. The baby flamingos are able to walk as soon as they get out of eggs and swim the next day. They don gray-color feathers and their bills are straight, unlike the hooked bills of adults. After two and half a months, baby flamingos are able to fly and in a year they are as large as their parents. But they have to wait till they are three years old before their plumage turns red.

Greater flamingos on Lake Nakuru are a spectacular scene that pulls in more than 100,000 tourists from all over the world every year.

(Translated by David)