The Osprey (Pandion haliaetus)—also known as the sea hawk, river hawk, or fish hawk—is a diurnal bird of prey and the only member of the Pandionidae family. In 2020 and 2021, I often saw them circling high in the sky, but in March 2022, I had the exciting opportunity to observe one perched closely in a treetop near a dam.
Ospreys have a very distinct "look" that makes them easy to identify, even from a distance. They have a white head with a dark brown stripe extending past the eye. Their upper body is dark brown, contrasting sharply with a white underside. They have a relatively short tail and extremely narrow wings. When soaring, their wings often form a distinct "M" shape, and you can see five "forked fingers" at the wingtips. Males and females are very similar in appearance, though females are often slightly larger and may have a darker "necklace" of feathers on their breast.
Ospreys are specialists; 99% of their diet consists of fish. They prefer to perch on high protrusions near the water to scout for movement. When hunting, they circle above the water and, upon spotting a target, they hover briefly before diving feet-first to snatch the fish with their powerful talons.
Seeing the Osprey at the Santa Fe Dam on almost the same dates in March (March 31, 2021, and March 14, 2022) led me to wonder about their migratory patterns. I learned that their migration is driven by accessibility to food. Fish are cold-blooded and sensitive to temperature changes. In the warm spring and summer months, fish stay near the surface where Ospreys can easily catch them. As temperatures drop, fish seek refuge in deeper, warmer waters, making them inaccessible to the Osprey. To avoid starvation, Ospreys must migrate to warmer climates where fish remain near the surface.
Interestingly, Ospreys are solitary migrants. Unlike many other North American raptors that travel in groups, Ospreys migrate independently. Even mated pairs and their juveniles do not travel together; each bird finds its own way to its wintering grounds.
鶚也被稱為海鷹、河鷹、魚鷹、王鴡和雎鳩。它是唯一的一種屬鶚科晝出夜息善於捕魚的猛禽。 2020 年和 2021 年，我經常看到它們在高空盤旋，但在 2022 年 3 月，我有幸近距離觀察到一隻鷂棲息在水壩附近的一棵樹梢上。
鶚的外形非常獨特，即使遠距離也能輕鬆辨認。它們的頭部呈白色，有明顯黑褐色粗過眼線。上身呈暗褐色，與白色的下身形成鮮明對比。它們的尾巴相對較短，翅膀也極為狹窄。翱翔時，翅膀常常呈現明顯的「M」形，指叉 5 枚。雄性和雌性外形非常相似，但雌性通常體型略大，胸部可能有一圈顏色較深的羽毛。
鶚是專食性動物，99% 的食物都是魚類。它們喜歡棲息在水面附近突出物上，以便觀察水面動靜。獵食時，它們會在水面上盤旋，一旦發現目標，會定點鼓翼，俯衝入水中以爪抓魚。
在三月幾乎相同的日期（2021 年 3 月 31 日和 2022 年 3 月 14 日）於聖達菲大壩看到魚鷹，讓我不禁好奇它們的遷徙規律。我了解到，它們的遷徙是由食物的可獲得性所驅動的。魚類是冷血動物，對溫度變化非常敏感。在溫暖的春夏季節，魚類會待在水面附近，魚鷹很容易就能捕捉到它們。隨著氣溫下降，魚類會游到更深更溫暖的水域，魚鷹就無法捕食它們了。為了避免餓死，魚鷹必須遷移到魚類仍待在水面附近的溫暖氣候地區。
有趣的是，魚鷹是獨居遷徙鳥類。與其他許多北美洲猛禽成群遷徙不同，魚鷹是單獨遷移的。即使是已配對的魚鷹及其幼鳥也不會一起遷徙；每隻鳥都會個自遷徙前往越冬地。
Notes 筆記
- The osprey also called sea hawk, river hawk, and fish hawk — is a diurnal, fish-eating bird of prey in the Pandionidae family.
- It is a large raptor, reaching more than 60 cm (24 in) in length and 180 cm (71 in) across the wings. It is brown on the upperparts and predominantly greyish on the head and underparts.
- The osprey tolerates a wide variety of habitats, nesting in any location near a body of water providing an adequate food supply. The osprey is the second most widely distributed raptor species, after the peregrine falcon. It is found on all continents except Antarctica, although in South America it occurs only as a non-breeding migrant.
- An Osprey may log more than 160,000 migration miles during its 15-to-20-year lifetime.
- The osprey is piscivorous, with fish making up 99% of its diet. Ospreys have vision that is well adapted to detecting underwater objects from the air. Ospreys are excellent anglers. Over several studies, Ospreys caught fish on at least 1 in every 4 dives. The average time they spent hunting before making a catch was about 12 minutes. Occasionally, the osprey may prey on rodents, rabbits, hares, other birds, and small reptiles.
- The osprey differs in several respects from other diurnal birds of prey. Its toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved. The osprey and owls are the only raptors whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. This is particularly helpful when they grab slippery fish.
- The osprey breeds near freshwater lakes and rivers, and sometimes on coastal brackish waters. Ospreys usually mate for life. Rarely, polyandry has been recorded.
- Osprey eggs do not hatch all at once. Rather, the first chick emerges up to five days before the last one. The older hatchling dominates its younger siblings, and can monopolize the food brought by the parents. If food is abundant, chicks share meals in relative harmony; in times of scarcity, younger ones may starve to death.
- In Buddhism, the osprey is sometimes represented as the "King of Birds"
- The osprey is mentioned in the famous Chinese folk poem "guan guan ju jiu" (關關雎鳩); "ju jiu" 雎鳩 refers to the osprey, and "guan guan" (關關) to its voice. In the poem, the osprey is considered to be an icon of fidelity and harmony between wife and husband, due to its highly monogamous habits. Some commentators have claimed that "ju jiu" in the poem is not the osprey but the mallard duck, since the osprey cannot make the sound "guan guan".
- In heraldry, the osprey is typically depicted as a white eagle, often maintaining a fish in its talons or beak, and termed a "sea-eagle." It is historically regarded as a symbol of vision and abundance; more recently it has become a symbol of positive responses to nature, and has been featured on more than 50 international postage stamps.
- 鶚也被稱為海鷹，河鷹和魚鷹-是一種晝出夜息善於捕魚的猛禽屬鶚科。
- 鶚是體型大的猛禽，長約60公分(24英吋)，翼展達180公分(71英吋)。上身呈棕色，頭部及下身主要呈灰色。
- 鶚可以適應各種各樣的棲息環境，可在食物充足的水域周圍任何地點築巢。 鶚是僅次於遊隼的第二種分佈最廣的猛禽。除南極洲以外的所有大洲都可以找得到它。而在南美它是非繁殖季的候鳥。
- 魚鷹在其15至20年的生命中可能會記錄超過160,000英里的遷移里程。
- 魚鷹是魚食性的，魚占其飲食的99％。魚鷹有非常特殊從空中探測水下物體的視力。魚鷹是出色的垂釣者。 在數項研究中，魚鷹每4次潛水至少捕獲1條魚。 他們抓魚之前平均花費狩獵時間約12分鐘。偶爾它也會捕食囓齒動物，兔子，野兔，其他鳥類和小型爬行動物。
- 魚鷹與其他晝出夜息的猛禽在幾個方面有所不同。 它的腳趾等長，跗骨是網狀的，而且爪子是圓形的，而不是開槽形的。 魚鷹和貓頭鷹是唯一外趾可翻轉的猛禽，前面有兩個腳趾，後面有兩個腳趾，使它們能夠抓住獵物，在抓住滑的魚時特別有用。
- 魚鷹通常在淡水湖泊和河流附近繁殖，有時在沿海鹹水上繁殖。魚鷹通常是一夫一妻。 很少有一妻多夫的記錄。
- 魚鷹的卵不會一次全部孵化。 最後一隻小魚鷹可能在第一隻小魚鷹出生後的五天孵出。 較先孵化出的魚鷹比其年輕的兄弟姐妹佔優勢地位，可以壟斷父母帶回來的食物。 如果食物多，小魚鷹們會和諧的分食。 但食物匱乏的時候，年紀較小的魚鷹可能會餓死。
- 在佛教中，魚鷹有時被稱為“鳥類之王”
- 中國著名的民間詩詞“關關雎鳩”中提到了魚鷹。 “ ju jiu”是指魚鷹，而“關關”是指其聲音。 在這首詩中，由於魚鷹一夫一妻制的習性，它被視為夫妻之間忠實和和諧的象徵。 一些評論家聲稱，詩歌中的“雎鳩”不是魚鷹，而是綠頭鴨，因為魚鷹不能發出“關”的聲音。
- 在紋章學中，魚鷹常被描繪成一隻白鷹，因為它的爪或喙可叼一條魚，故被稱為“海鷹”。 過去它被視為有遠見和豐裕的象徵； 最近它已成為對自然正面回應的象徵，在50多種國際郵票上可得到它。
References 參考資料
- Wikipedia: Osprey
- All about birds: Osprey
- 維基百科: 鹗
- Avian Report: Osprey Migration
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