小杜鹃在强脚树莺巢中寄生繁殖

2006年6~7月作者在贵州省宽阔水自然保护区首次发现小杜鹃(Cuculus poliocephalus)在强脚树莺(Cettiafortipes)巢中寄生(封4图片),并对这一现象进行了连续观察,对小杜鹃的雏鸟生长进行了测量。报道如下:宽阔水自然保护区位于贵州省遵义市绥阳县北部(28°06′25″~28°19′25″N     

大杜鹃在荒漠伯劳巢中寄生繁殖

2010年5～7月在安西极旱荒漠国家级自然保护区发现3巢荒漠伯劳被大杜鹃寄生,寄生率10.34%.荒漠伯劳产白色和粉红色两种颜色的卵,大杜鹃产白色寄生卵于卵色为白色的宿主巢中.寄生卵均产于6月,当月寄生率达42.86%.大杜鹃雏鸟19日龄离巢,离巢时体重66.24 g.     

大杜鹃在白腹短翅鸲巢中寄生繁殖

2009年至2012年期间,在甘肃莲花山自然保护区共发现91个白腹短翅鸲(Hodgsonius phaenicuroides)巢,其中15巢被大杜鹃(Cuculus canorus)寄生,寄生率为16.48%。根据对13枚寄生的大杜鹃卵的观察,其中12枚卵色为浅蓝色,与白腹短翅鸲的深蓝绿色卵差异明显,仅1枚与白腹短翅鸲卵色一致。大杜鹃与白腹短翅鸲的卵重(t =11.208, df=38, P<0.001)和卵短径(t=0.970,df=38, P<0.001)差异极显著。白腹短翅鸲具有识别大杜鹃卵的能力,15巢中只有4巢接受寄生卵并继续孵化,7巢成功识别,剩余4巢无法确定是否识别。白腹短翅鸲为雌鸟单独孵卵,推测识别大杜鹃卵可能只与雌鸟有关。     

中杜鹃在3种宿主巢中寄生繁殖

了解杜鹃对其宿主的选择和寄生情况,能为两者间的协同进化研究提供重要的基础资料。2012和2013年每年的4～8月,在贵州宽阔水国家级自然保护区对不同生境类型中的鸟巢进行搜索监测,记录到4例中杜鹃(Cuculus saturatus)寄生繁殖现象,其宿主分别是暗绿绣眼鸟(Zosterops japonicus)、棕腹柳莺(Phylloscopus subaffinis)和黄喉鹀(Emberiza elegans),其中棕腹柳莺和暗绿绣眼鸟是首次记录到被中杜鹃寄生。中杜鹃卵重(2.39±0.14)g(n=3),体积(2.24±0.18)cm3(n=3),通过T检验方法发现中杜鹃卵极显著大于暗绿绣眼鸟和棕腹柳莺卵(P0.001),同时在形状上也与两者极不相似,中杜鹃卵呈明显的长椭圆形,与黄喉鹀的卵在大小上无显著差异(P=0.1)。反射光谱的分析结果发现,寄生于不同宿主巢的中杜鹃卵在背景色和斑点上都具有一定差异,这表明中杜鹃的卵可能存在基因族群的分化。     

棕腹杜鹃在山蓝仙鹟巢中寄生繁殖

正棕腹杜鹃(Hierococcyx nisicolor)是鹃形目(Cuculiformes)杜鹃科(Cuculidae)的寄生性繁殖鸟类(郑光美2011,Dickinson et al.2013)。目前棕腹杜鹃已记录的宿主主要为鹟科(Muscicapidae)鸟类,例如北灰鹟(Muscicapa dauurica)、白腹蓝姬鹟(Cyanoptila cyanomelana)等(Payne 2005,Erritz?e et al.2012)。棕腹杜鹃在中国的宿主报道很少,仅粟通萍等(2016)报道了在广西大明山的棕腹杜鹃寄生于海南蓝仙鹟(Cyornis hainanus)一例。     

大杜鹃的巢寄生

巢寄生（brood parasitism）：是某些鸟类将卵产在其他鸟的巢中,由其他鸟（义亲）代为孵化和育雏的一种特殊的繁殖行为。本图片为东方大苇莺在哺育大杜鹃雏鸟。     

陕西长青自然保护区发现棕腹杜鹃和八声杜鹃

于2014年7月16日和2015年6月9日,先后在陕西长青国家级自然保护区内发现并拍摄到棕腹杜鹃（Cuculus nisicolor）和八声杜鹃（Cacomantis merulinus）,为陕西省首次记录。     

小杜鹃对强脚树莺的巢寄生及其卵色模拟

于1999-2009年的鸟类繁殖季(4-8月)对贵州宽阔水自然保护区内的强脚树莺(Cettia fortipes)的繁殖进行监测,并采用光纤光谱仪,通过主成分分析、反射光谱、罗宾逊投射等方法对强脚树莺的卵色与小杜鹃(Cuculus poliocephalus)对其寄生的卵色模拟程度进行分析。研究结果表明,强脚树莺的繁殖成效在不同年份间均无显著差异,但其巢被捕食率和巢被寄生率都较高,分别为49.26%和9.18%。通过反射光谱分析,表明小杜鹃卵在色调和色度上高度模拟强脚树莺的卵,但其亮度高于宿主卵,而且在人眼无法探测的紫外光部分存在差异。     

大杜鹃对家燕的巢寄生

了解杜鹃(Cuculus spp.)对不同宿主鸟类的巢寄生,是研究杜鹃与其宿主之间协同进化的重要基础资料。大杜鹃(Cuculus canorus)和家燕(Hirundo rustica)分布遍及全国,且为同域分布,但两者之间的寄生现象尚未有过系统调查。2012年和2014年4~8月,对繁殖于吉林市昌邑区桦皮厂镇(34°58′44.18″N,126°13′26.83″E,海拔184 m)和海南岛的家燕种群进行调查,结果表明,吉林市昌邑区桦皮厂镇家燕种群的寄生率为2.4%(1/42),而在海南岛所调查的1 719个家燕巢未发现杜鹃寄生现象。同时在网络上搜集家燕巢寄生的报道案例,共记录到13巢家燕被大杜鹃寄生繁殖,均发生在北方的家燕种群。     

鹰鹃在橙翅噪鹛巢中寄生繁殖

2011年和2012年每年的5月到8月,在甘肃莲花山地区共发现了5例鹰鹃(Hierococcyx sparverioides)在橙翅噪鹛(Garrulax elliotii)巢中寄生繁殖的案例.鹰鹃卵为椭圆形,浅蓝色,卵壳上没有斑点.测量了其中2枚卵,卵重分别为6.9g和7.2g,长径×短径分别为29.76 mm×20.40 mm和28.40mm×21.68 mm.鹰鹃幼鸟在出壳后的第20天离巢.     

How can distinct egg polymorphism be maintained in the rufescent prinia (Prinia rufescens)–plaintive cuckoo (Cacomantis merulinus) interaction—a modeling approach

In avian brood parasitism, both the host and the parasite are expected to develop various conflicting adaptations; hosts develop a defense against parasitism, such as an ability to recognize and reject parasitic eggs that look unlike their own, while parasites evolve egg mimicry to counter this host defense. Hosts may further evolve to generate various egg phenotypes that are not mimicked by parasites. Difference in egg phenotype critically affects the successful reproduction of hosts and parasites. Recent studies have shown that clear polymorphism in egg phenotype is observed in several host–parasite interactions, which suggests that egg polymorphism may be a more universal phenomenon than previously thought. We examined the mechanism for maintaining egg polymorphism in the rufescent prinia (Prinia rufescens) that is parasitized by the plaintive cuckoo (Cacomantis merulinus) from a theoretical viewpoint based on a mathematical model. The prinia has four distinct egg phenotypes: immaculate white, immaculate blue, white with spots, and blue with spots. Only two egg phenotypes, white with spots and blue with spots, are found in the cuckoo population. We show that the observed prinia and cuckoo phenotypes cannot be at an equilibrium and that egg polymorphism can be maintained either at stationary equilibrium or with dynamic, frequency oscillations, depending on the mutation rates of the background color and spottiness. Long‐term monitoring of the prinia–cuckoo interaction over a wide geographic range is needed to test the results of the model analyses.     

长白山中华秋沙鸭的种内巢寄生

雁形目鸟类的种内巢寄生现象十分普遍,但有关中华秋沙鸭(Mergussquamatus)的种内巢寄生现象未见报道。2019年4和5月,从长白山1个中华秋沙鸭人工巢的视频监控发现,1只雌鸭在亲鸟孵卵时强行进入巢箱趴卧约29 min。其后根据该巢窝卵数的增加、超常窝卵数和窝卵不同步孵化3个指标,确认该巢存在种内巢寄生现象。宿主对进入巢内寄生的个体表现出强烈的攻击行为,但对寄生卵未表现出明显的拒卵行为。由于区域内仍有较多巢箱未被利用,中华秋沙鸭的种内巢寄生行为是否源于对有限巢址资源的竞争,有待进一步研究。     

The Value of Artificial Stimuli in Behavioral Research: Making the Case for Egg Rejection Studies in Avian Brood Parasitism

Experimentation is at the heart of classical and modern behavioral ecology research. The manipulation of natural cues allows us to establish causation between aspects of the environment, both internal and external to organisms, and their effects on animals' behaviors. In recognition systems research, including the quest to understand the coevolution of sensory cues and decision rules underlying the rejection of foreign eggs by hosts of avian brood parasites, artificial stimuli have been used extensively, but not without controversy. In response to repeated criticism about the value of artificial stimuli, we describe four potential benefits of using them in egg recognition research, two each at the proximate and ultimate levels of analysis: (1) the standardization of stimuli for developmental studies and (2) the disassociation of correlated traits of egg phenotypes used for sensory discrimination, as well as (3) the estimation of the strength of selection on parasitic egg mimicry and (4) the establishment of the evolved limits of sensory and cognitive plasticity. We also highlight constraints of the artificial stimulus approach and provide a specific test of whether responses to artificial cues can accurately predict responses to natural cues. Artificial stimuli have a general value in ethological research beyond research in brood parasitism and may be especially critical in field studies involving the manipulation of a single parameter, where other, confounding variables are difficult or impossible to control experimentally or statistically.     

北京小龙门东方中杜鹃多重寄生冕柳莺的报道

多重巢寄生是1只或多只寄生性鸟类在1个宿主巢内产2枚或多枚卵的特殊行为方式。对于雏鸟具有排他性的杜鹃而言,多重寄生被认为是种内个体之间或种间的一种竞争,但相关报道较少。通过野外观察和分子生物学检测技术,我们在北京小龙门国家森林公园确定了一个被东方中杜鹃(Cuculus optatus)多重寄生的冕柳莺(Phylloscopus coronatus)巢。     

Relationship Between Nest Predation Suffered by Hosts and Brown-Headed Cowbird Parasitism: A Comparative Study

There are at least four main hypotheses that may explain how the evolution of host selection by avian brood parasites could be linked to nest predation among their potential hosts. First, selection may have favoured parasite phenotypes discriminating among hosts on the basis of expected nest failure. Second, parasitized nests may be more easily detected by predators and extra costs of parasitism may accelerate the evolution of host defences. Third, selection may have favoured predator phenotypes avoiding parasitized nests because parasitism enhances nest defence. Fourth, female brood parasites may directly or indirectly induce host nesting failures in order to enhance future laying opportunities. We collected data on brood parasitism and nest failure due to predation to test these hypotheses in a comparative approach using North American passerines and their brood parasite, the brown-headed cowbird Molothrus ater. Under the hypotheses 1 or 3 we predicted brood parasitism to be negatively associated with nest predation across species, whereas this relation is expected to be positive if hypotheses 2 or 4 are true. We demonstrate that independent of host suitability, nest location, habitat type, length of the nestling period, body mass and similarity among species due to common ancestry, species experiencing relatively high levels of nest predation suffered lower levels of cowbird parasitism. Our results suggest a previously ignored role for nest predation suffered by hosts on the dynamics of the coevolutionary relationships between hosts and avian brood parasites. Co-ordinating editor: Dr. F. Stuefer     

Brood parasitism selects for no defence in a cuckoo host

In coevolutionary arms races, like between cuckoos and their hosts, it is easy to understand why the host is under selection favouring anti-parasitism behaviour, such as egg rejection, which can lead to parasites evolving remarkable adaptations to ‘trick’ their host, such as mimetic eggs. But what about cases where the cuckoo egg is not mimetic and where the host does not act against it? Classically, such apparently non-adaptive behaviour is put down to evolutionary lag: given enough time, egg mimicry and parasite avoidance strategies will evolve. An alternative is that absence of egg mimicry and of anti-parasite behaviour is stable. Such stability is at first sight highly paradoxical. I show, using both field and experimental data to parametrize a simulation model, that the absence of defence behaviour by Cape bulbuls (Pycnonotus capensis) against parasitic eggs of the Jacobin cuckoo (Clamator jacobinus) is optimal behaviour. The cuckoo has evolved massive eggs (double the size of bulbul eggs) with thick shells, making it very hard or impossible for the host to eject the cuckoo egg. The host could still avoid brood parasitism by nest desertion. However, higher predation and parasitism risks later in the season makes desertion more costly than accepting the cuckoo egg, a strategy aided by the fact that many cuckoo eggs are incorrectly timed, so do not hatch in time and hence do not reduce host fitness to zero. Selection will therefore prevent the continuation of any coevolutionary arms race. Non-mimetic eggs and absence of defence strategies against cuckoo eggs will be the stable, if at first sight paradoxical, result.