稀有的猛禽混血兒很可能是絕望的產(chǎn)物，而不是愛(ài)情

稀有的猛禽混血兒很可能是絕望的產(chǎn)物，而不是愛(ài)情

It is a truth universally acknowledged that a lone common black hawk in no possession of a child, must be in want of a mate, no matter their genus… So begins the tale of one common black hawk’s foray with a red-shouldered hawk, despite their genetic differences. Yet this story does not end in tragedy, for this intergeneric affair has resulted in the natural production of an extremely rare hybrid, an event recorded only a handful of times in wild hawks and eagles.

這是一個(gè)舉世公認(rèn)的真理:一只沒(méi)有孩子的普通黑鷹，一定想找個(gè)伴侶，無(wú)論他們是哪一種鳥(niǎo)……于是，一只普通黑鷹與一只紅肩鷹的故事就這樣開(kāi)始了，盡管它們的基因不同。然而，這個(gè)故事并沒(méi)有以悲劇告終，因?yàn)檫@種屬間事件導(dǎo)致了一種極其罕見(jiàn)的混血兒的自然繁殖，這種情況在野生鷹和老鷹身上只記錄了幾次。

The unconventional tale began in 2005, when Stan Moore, a raptor bander at Fairfax Raptor Research, noticed an unusual sight in the Laguna de Santa Rosa Wetlands Complex in Sonoma County, California: a common black hawk (Buteogallus anthracinus). More commonly found in corridors of gallery forests along flowing streams from the Southwestern United States through to South America, the common black hawk has only been spotted 16 times over a period of 33 years in California.

這個(gè)非傳統(tǒng)的故事開(kāi)始于2005年，費(fèi)爾法克斯猛禽研究中心的猛禽斑手斯坦·摩爾在加利福尼亞索諾瑪縣的拉古納德圣羅莎濕地發(fā)現(xiàn)了一個(gè)不尋常的景象:一只普通的黑鷹(Buteogallus anthracinus)。在從美國(guó)西南部到南美洲的流動(dòng)的溪流中，更常見(jiàn)的是在畫(huà)廊森林的走廊里，常見(jiàn)的黑鷹在加州33年的時(shí)間里只被發(fā)現(xiàn)過(guò)16次。

Katy Pallister

Although a temporary resident for the first two years, the common black hawk Moore had spotted started to hold a permanent territory from April 2008. During this time the hawk, later determined as female after Moore tagged her in 2009, had already begun to engage in mating behaviors, enticing the native red-shouldered hawks (Buteo lineatus) into her territory. But she did not receive a warm reception, having been harassed by a resident pair of red-shouldered hawks during several of her aerial courtship displays.

雖然頭兩年是臨時(shí)居民，但摩爾發(fā)現(xiàn)的普通黑鷹從2008年4月開(kāi)始擁有永久領(lǐng)地。在這段時(shí)間里，這只2009年被摩爾標(biāo)記為雌性的鷹已經(jīng)開(kāi)始進(jìn)行交配活動(dòng)，引誘本地紅肩鷹(Buteo lineatus)進(jìn)入她的領(lǐng)地。但她并沒(méi)有受到熱情的接待，在她的幾次空中求愛(ài)表演中，一對(duì)當(dāng)?shù)氐募t肩鷹對(duì)她進(jìn)行了騷擾。

The red-shouldered Hawks breed across North America. Dirk M. de Boer/Shutterstock

Their refusal of her advances is not wholly surprising, given that the two species of hawks belong to entirely different genera, only sharing common ancestry at the “family” level. Therefore, the black hawk’s uniform dark plumage would be seen as a world away from the red hawk’s rusty and white speckled front. The female black hawk’s superior size may also have been on the male red hawk’s mind, as the size contrast would have posed a significant threat to them.

他們拒絕她的求愛(ài)并不完全令人驚訝，因?yàn)檫@兩種鷹屬于完全不同的屬，只是在“家族”層面上有共同的祖先。因此，黑鷹統(tǒng)一的黑色羽毛將被視為一個(gè)世界遠(yuǎn)離紅鷹生銹和白色斑點(diǎn)的前面。雌黑鷹的優(yōu)越尺寸可能也在雄紅鷹的腦海中，因?yàn)槌叽绲膶?duì)比會(huì)對(duì)它們構(gòu)成重大的威脅。

So what was it that attracted the female black hawk to the male red hawk in the first place? Well, according to a paper published earlier this year in the Journal of Raptor Research, the answer is probably not love but in fact desperation.

那么到底是什么吸引了雌黑鷹和雄紅鷹呢?根據(jù)今年早些時(shí)候發(fā)表在《猛禽研究雜志》上的一篇論文，答案可能不是愛(ài)，而是絕望。

Hubbs’ principle, referred to as the “desperation hypothesis,” is one way in which hybridization can be explained. This is when “a rare individual fails to find a conspecific mate and settles on a mate of a common species,” a rarity caused, for example, by vagrancy, endangerment, or natural range expansion, according to the authors.

哈布斯的原理，被稱為“絕望假說(shuō)”，是解釋雜交的一種方法。這是指“一個(gè)罕見(jiàn)的個(gè)體未能找到一個(gè)同族伴侶，而選擇了一個(gè)普通物種的伴侶”，根據(jù)作者的說(shuō)法，這種罕見(jiàn)是由流浪、瀕?；蜃匀环秶鷶U(kuò)大等原因造成的。

The female black hawk engaged with a male red hawk in aerial courtship (a- photo by N. Dunlop) and simultaneously tending to a nest (b- photo by S.Moore). Moore and Coulson, 2020 (Journal of Raptor Research)

Therefore, away from her species, the vagrant black hawk in western California had to change up her type in order to mate, and the red-shouldered hawks were the most abundant species available, although their dietary overlap and strong associations with aquatic habitats may have helped them along.

因此，遠(yuǎn)離她的物種，在西加利福尼亞的流浪黑鷹不得不改變她的類(lèi)型為了交配，和紅肩鷹是最豐富的物種，雖然他們的飲食重疊和與水生棲息地的強(qiáng)烈聯(lián)系可能有助于他們。

After several years of mating behavior, a suspected hybrid juvenile was sighted in 2012. Ramping up their observations, the researchers recorded a total of three courtship flights, two copulations, and two simultaneous nest attendances between the female black hawk and a male red hawk, which ultimately resulted in another hybrid birth in 2014.

經(jīng)過(guò)幾年的交配行為，2012年發(fā)現(xiàn)了一只疑似雜交幼崽。根據(jù)他們的觀察，研究人員總共記錄了三次求愛(ài)飛行、兩次交配以及雌黑鷹和雄紅鷹同時(shí)筑巢的次數(shù)，這最終導(dǎo)致了2014年的另一次雜交。

Photos (a-c) shows the common black hawk x red-shouldered hawk hybrid at 56 days old, and photo (d) at 46 days old. (Photos by S. Moore) Moore and Coulson, 2020 (Journal of Raptor Research)

Marrying the two species’ appearance, the offspring was large and had a dark plumage, similar to its mother, and had a hooked bill and patches of cream and dark brown, like its father. Although the offspring’s appearance and the behavior between the two hawks point to a hybrid, a genetic analysis of the juvenile’s blood sample would confirm it.

與這兩個(gè)物種的外貌相結(jié)合，后代體型龐大，有著與母親相似的深色羽毛，有著鉤狀的喙，和父親一樣，身上有幾塊奶油色和深褐色的斑點(diǎn)。盡管這只幼鷹的外表和兩只鷹之間的行為表明它是雜交后代，但對(duì)這只幼鷹血液樣本的遺傳分析可以證實(shí)這一點(diǎn)。

But what of the adult hawks’ fate? Reports and photographs from 2019 show the pair engaged in aerial courtship displays. The less cynical amongst us may wonder that what perhaps was once an act of desperation has turned into love after all.

但是成年鷹的命運(yùn)如何呢?2019年的報(bào)道和照片顯示，這對(duì)情侶進(jìn)行了空中求愛(ài)表演。我們中那些不那么憤世嫉俗的人可能會(huì)想，也許曾經(jīng)的絕望行為最終變成了愛(ài)。