巢寄生行为

巢寄生是一种鸟类将卵产在其它鸟的鸟巢中,由义亲代为孵化和育雏的一种特殊的繁殖行为。照片中所示的草地鹨（Ａｎｔｈｕｓｐｒａｔｅｎｓｉｓ）喂食大杜鹃,就是一种种间巢寄生类型。大杜鹃是现有巢寄生鸟类８０多种中最典型的一种鸟,它可把卵寄生在１２５种其它鸟类的巢中。巢寄生行为表现在：宿主的选择,大杜鹃在繁殖期寻找与孵化期和育雏期相似、雏鸟食性基本相同、卵形与颜色易仿的宿主,多为雀形目鸟类。寄生时间上,大杜鹃多在宿主开始孵卵之前,乘宿主离巢外出时快速寄生产卵。巢寄生的协同进化,表现在宿主卵的形态特征上。寄生…     

八声杜鹃在两种缝叶莺巢中寄生繁殖

了解杜鹃对不同寄主的选择和利用,可为研究两者之间的协同进化提供重要基础资料。2012至2014年每年的3~6月,在广西弄岗地区共记录到3例八声杜鹃(Cacomantis merulinus)的寄生繁殖,其中,2例寄生于栗头缝叶莺(Orthotomus cuculatus)的巢(寄生率1.4%,n=142),其中2枚杜鹃卵均为白色具棕色斑点;1例寄生于黑喉缝叶莺(O.atrogularis)(寄生率10%,n=10),杜鹃卵为白色具棕色斑点。栗头缝叶莺为八声杜鹃寄主的首次报道,而两种缝叶莺均首次在中国记录到被八声杜鹃寄生。八声杜鹃的卵重为(1.45±0.09)g,卵体积为(1.46±0.07 cm3)(n=3),其卵大小和重量均显著大于栗头缝叶莺和黑喉缝叶莺的卵(t检验,P0.001)。     

甘肃安西荒漠伯劳的繁殖生态

2010年4～8月在甘肃安西极旱荒漠国家级自然保护区,采用样点法对荒漠伯劳(Lanius isabellinus isabellinus)的繁殖生态进行了研究,采用单因素方差分析(ANVON)对荒漠伯劳卵体积与卵序之间的关系进行了研究,用二元Logistic回归对雏鸟生长曲线进行拟合。结果表明,荒漠伯劳的繁殖时间为4月底至8月初,每巢产卵3～6枚,平均窝卵数为4.67±0.57(n=21),卵体积为(3.14±0.32)cm3(n=95),卵鲜重(3.48±0.20)g(n=20),卵体积随着产卵顺序显著减小(R=-0.427,P=0.021,n=29),其采取的是"窝雏减少"的繁殖策略。雌鸟产首枚卵后即开始孵卵,雄鸟负责情饲及警戒。温度自动记录仪测量平均孵卵温度为(38.19±0.77)℃(n=2),雌鸟在巢率为93.95%。平均孵卵时间为(15.33±0.52)d(n=6)。荒漠伯劳雏鸟留巢期12～15 d,幼鸟离巢后亲鸟继续饲喂幼鸟,整个育雏期最长达31 d。研究地区荒漠伯劳种群的孵卵率为82.50%(n=80),卵成功率为46.25%(n=80),雏鸟离巢率为56.06%(n=66),巢成功率58.62%(n=29)。在2010年环志标记的12对繁殖鸟中只有1对繁殖了第二窝。     

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。     

三个东方大苇莺种群大杜鹃寄生率的变异

东方大苇莺Acrocephalus orientalis是大杜鹃Cuculus canorus的主要寄主之一。本文对东方大苇莺的3个地理种群进行杜鹃寄生率的时空比较。发现不同东方大苇莺种群被大杜鹃的巢寄生率在21.4%和65.5%之间,差异显著;不过,地理位置相近的两个种群在巢寄生率上则没有显著差异。另外,同一地理种群的巢寄生率年间也存在显著差异。     

荒漠伯劳的繁殖及雏鸟生长发育

2006～2007年对新疆石河子市荒漠伯劳(Lanius isabellinus phoenicuroides)的巢、卵及雏鸟的生长发育状况进行了研究.结果表明,荒漠伯劳窝卵数平均5.67枚,孵卵期17 d,育雏期15 d.育雏主要由雌鸟担任.采用Logistic方程对雏鸟发育过程中主要生长指标的生长方程进行了曲线拟合,相关指标生长方程的拟合度均在0.99以上.     

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。     

荒漠伯劳巢址选择和繁殖成功

2011年5～7月对甘肃安西极旱荒漠国家级自然保护区(N40°21'～40°22',E96°13'～96°14',海拔1 306 m)荒漠伯劳(Lanius isabellinus)巢址选择和繁殖成功进行研究。调查了58巢的巢址因子,巢主要位于营巢树主枝上,巢距地面高度多为2.0～2.5 m。主成分分析结果表明,巢距地面高度、营巢树高度、营巢树胸径和营巢处树干直径是影响荒漠伯劳巢址选择的主要因素,这也是荒漠伯劳适应繁殖地大风天气的结果。既调查巢址数据又明确繁殖情况的49个巢中,红柳(Tamarix ramosissima)(5棵)上巢的繁殖成功率明显高于沙枣(Elaeagnus angusifolia)(43棵)和胡杨(Populus euphratica)(1棵)上的巢,原因可能是红柳郁闭度大。已知窝卵数和繁殖情况的30个巢中,窝卵数分别为2(1巢)、4(7巢)、5(18巢)、6(4巢)。卡方检验结果表明,窝卵数和繁殖成功率之间差异不显著(χ2=3.921,df=3,P0.05)。发现的63个巢中跟踪监测了54个巢(包括调查巢址数据的和未调查巢址数据的)的繁殖情况,54巢中37巢繁殖成功,成功率为68.52%。所有繁殖失败的巢均为产卵阶段或育雏早期阶段由于同类的破坏而导致繁殖失败,繁殖失败巢的数量随着相邻最近巢的距离的增加而减少,因而,繁殖失败可能与种群密度以及种内竞争有关。     

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。     

中杜鹃捕食比氏鹟莺的卵

许多杜鹃在产下寄生卵之前通常会先叼走或吃掉宿主的1~2枚卵,这说明杜鹃不仅是寄生性繁殖的鸟类,同时可能也是潜在的捕食者。关于杜鹃对其宿主巢捕食的动机,一般认为一是由于杜鹃发现宿主巢时,已不适合寄生,将其捕食或毁坏可迫使宿主重新筑巢,从而杜鹃会获得寄生机会;二则可能由于宿主识别并拒绝了寄生卵,一些杜鹃会通过捕食或破坏宿主的巢,作为对宿主的一种惩罚性报复。2015年6月,在贵州宽阔水自然保护区,通过录像首次记录到中杜鹃(Cuculus saturatus)捕食整巢比氏鹟莺(Seicercus latouchei)卵的行为,表明中杜鹃不仅是许多宿主鸟类的巢寄生者,同时也可能是其巢捕食者。     

Cuckoo parasitism in a cavity nesting host: near absent egg‐rejection in a northern redstart population under heavy apparent (but low effective) brood parasitism

Brood parasite – host systems continue to offer insights into species coevolution. A notable system is the redstart Phoenicurus phoenicurus parasitized by the ‘redstart‐cuckoo’ Cuculus canorus gens. Redstarts are the only regular cuckoo hosts that breed in cavities, which challenges adult cuckoos in egg laying and cuckoo chicks in host eviction. We investigated parasitism in this system and found high overall parasitism rates (31.1% of 360 redstart nests), but also that only 33.1% of parasitism events (49 of 148 eggs) were successful in laying eggs into redstart nest cups. The majority of cuckoo eggs were mislaid and found on the rim of the nest; outside the nest cup. All available evidence suggests these eggs were not ejected by hosts. The effective parasitism rate was therefore only 12.8% of redstart nests. Redstarts responded to natural parasitism by deserting their nests in 13.0% of cases, compared to desertion rates of 2.8% for non‐parasitized nests. Our egg parasitism experiments found low rates (12.2%) of rejection of artificial non‐mimetic cuckoo eggs. Artificial mimetic and real cuckoo eggs added to nests were rejected at even lower rates, and were always rejected via desertion. Under natural conditions, only 21 cuckoo chicks fledged of 150 cuckoo eggs laid. Adding to this low success, is that cuckoo chicks are sometimes unable to evict all host young, and were more likely to die as a result compared to cuckoo chicks reared alone. This low success seems to be mainly due to the cavity nesting strategy of the redstart which is a challenging obstacle for the cuckoo. The redstart‐cuckoo system appears to be a fruitful model system and we suggest much more emphasis should be placed on frontline defences such as nest site selection strategies when investigating brood parasite–host coevolution.     

Egg Rejection and Brain Size among Potential Hosts of the Common Cuckoo

Interspecific brood parasitism by the common cuckoo (Cuculus canorus) lowers host fitness, and has selected for discrimination and rejection of parasitic eggs in their commonly parasitized hosts. Cognitive demands needed to discriminate and reject cuckoo eggs may have led to augmentation of relative brain size among passerine hosts parasitized by cuckoos. This hypothesis predicts for across species positive relationships of brain size with rejection rate, host suitability and parasitism level. Here we test these predictions while controlling for phylogenetic, ecological and developmental factors known to affect brain size and egg rejection in a comparative study using the cuckoo and their hosts in Europe as a model system. Contrary to expected the rate of rejection of non‐mimetic cuckoo eggs covaried negatively with relative brain size across bird species. Either suitability as cuckoo host, which reflects long‐time duration of exposure to cuckoo parasitism, and level of parasitism, did not relate to brain size. Our results do not support the hypothesis that cuckoo parasitism was a main direct force affecting brain size variation across passerine hosts.     

Brood parasitism and egg matching in the Red-chested Cuckoo Cuculus solitarius in southern Africa

Host usage and relative rates of egg matching were investigated in the Red-chested Cuckoo Cuculus solitarius in southern Africa, using nest record cards and museum collections. Eighteen host species were found to be parasitized at varying degrees of intensity (0.14–12.5%). The most commonly recorded parasitized host, the Cape Robin Cossypha caffra , had a relatively low rate of parasitism (2.46%). The host species experiencing the most recorded pressure from parasitism was the Bearded Robin Erythropygia quadrivirgata , with 12.5% parasitism. Human perception of cuckoo/host egg matching was assessed for parasitized clutches of host species in museum egg collections. Eggs of three different cuckoo egg morphs were scored as matching those of the host species on a 1–5 scale. Perfect/good matching was recorded for eggs found in Chorister Cossypha dichroa , Heuglin's Cossypha heuglini and Natal Robins' Cossypha natalensis clutches. Poor and very poor matching was evident for cuckoo eggs found in four host species' clutches: the Cape Robin, Stonechat Saxicola torquata , Cape Rockthrush Monticola rupestris and Black Flycatcher Melaenornis pammelaina . Available evidence suggests that the Red-chested Cuckoo parasitizes hosts in a particular environment (low vegetation and trees). Good to intermediate matching was recorded with only 47% of host eggs, and with only 28.5% of Cape Robin clutches. A relatively high degree of host specificity, however, is suggested by the nest record card data, which indicate that species with large numbers of records are not those with the highest rates of parasitism.     

The common cuckoo Cuculus canorus and its cavity nesting host, the redstart Phoenicurus phoenicurus: a peculiar cuckoo-host system?

We examined redstart Phoenicurus phoenicurus populations over a period of fifteen years to study interactions between the cuckoo Cuculus canorus and its cavity-nesting host. Over 380 redstart nests were checked and more than 100 cuckoo eggs were found during the study period. The average parasitism rate was 20%. The cuckoos' breeding success was extremely low, only 18 chicks surviving to the fledgling stage. When redstarts were parasitized experimentally with artificial cuckoo eggs, they rejected eight percent of mimetic eggs and 44% of non-mimetic eggs. We were not able to record any rejection of the real cuckoo eggs. However, about 30% of the real cuckoo eggs were found outside the redstart's nest cup. This could be the result of laying failures by the cuckoo, rather than of a strong rejection behaviour by the redstart. We suggest that redstarts' cavity nesting itself was a factor that reduced the cost of the parasitism dramatically. Firstly, it makes it difficult for the female cuckoo to lay her egg correctly in the nest and secondly, it is more difficult for the cuckoo chick to evict the host's eggs or nestlings effectively from the nest. Only 54% of the cuckoo chicks were able to evict all the host eggs or chicks from the nest. When reared in mixed broods, cuckoo chicks survived only in every second case to fledgling age, while at least one redstart chick from every brood managed to leave the nest.     

Behaviour of African turdid hosts towards experimental parasitism with artificial red-chested cuckoo Cuculus solitarius eggs

The red-chested cuckoo Cuculus solitarius parasitises many passerines in Africa, but some common species sympatric with this brood parasite are rarely used as hosts. We tested the responses of three turdid hosts to parasitism with artificial cuckoo eggs. The kurrichane thrush Turdus libonyana , which is not regularly parasitized by the cuckoo, rejected 60% of mimetic model eggs and 81% of non-mimetic eggs. We observed female thrush behaviour during the first visit after parasitism, and thrushes appeared to be initially fooled by mimetic eggs in completed clutches in all cases, and incubated. By contrast, in half of the experiments with non-mimetic eggs, these were ejected by the thrushes, with the host grasping the egg and flying away with it. The time spent nest checking prior to ejection was only one third of the time spent nest checking when females decided to incubate the clutch, suggesting that females were immediately aware of a foreign egg in the nest. By contrast, southern olive thrushes T. olivaceous rejected all non-mimetic and accepted all mimetic model eggs, whereas cape robins Cossypha caffra accepted all model eggs, irrespective of whether or not they were mimetic. Our results support the hypothesis that rejection behaviour in these two thrush species evolved as a defence against interspecific nest parasitism, with thrushes appearing to be ahead in this particular host-parasite arms race. The cape robin, by contrast, appears not to reject cuckoo eggs, either because it is to unable to recognize them, or because the costs associated with removal may be too high.     

No change in common cuckoo Cuculus canorus parasitism and great reed warblers’ Acrocephalus arundinaceus egg rejection after seven decades

The coevolutionary process among avian brood parasites and their hosts involves stepwise changes induced by the antagonistic selection pressures of one on the other. As long‐term data on an evolutionary scale is almost impossible to obtain, most studies can only show snapshots of such processes. Information on host behaviour, such as changes in egg rejection rates and the methods of rejection are scarce. In Hungary there is an interesting case between the common cuckoo Cuculus canorus and the great reed warbler Acrocephalus arundinaceus, where the level of parasitism is unusually high (around 50%). We compared host rejection rates and methods of rejection from within our own project to that of an early study carried out and published almost 70 yr ago in the same region. Our comparisons revealed high and stable rates of parasitism (range: 52–64%), and marked fluctuations in the ratio of multiply parasitized nests (range: 24–52%). No difference was revealed in egg rejection rates after 7 decades (34–39%). Linear mixed‐effects modelling revealed no year effect on the type host responses toward the parasitic egg(s) during the years of study (categorized as acceptance, ejection, burial, and nest desertion). Cuckoo egg rejection was primarily affected by the type of parasitism, as more cuckoo eggs were rejected during single parasitism than from multiply parasitized nests. Our comparison did not reveal any directional changes in this cuckoo–host relationship, except a slight decrease in the frequency of multiple parasitism, which is likely to be independent from coevolutionary processes.     

Factors influencing the risk of common cuckoo Cuculus canorus parasitism on marsh warblers Acrocephalus palustris

Using multiple logistic regression analysis, we investigated the influence of nest site characteristics, laying date and nest size in marsh warblers Acrocephalus palustris on the risk of parasitism by common cuckoos Cuculus canorus . Marsh warblers breed in more diverse and dense herbaceous vegetation than other cuckoo hosts investigated in comparable studies. The "perch proximity" hypothesis was supported as parasitized nests were situated closer to trees than non-parasitized ones. Furthermore, demonstrated for the first time in a cuckoo host, tree height was an important predictor of parasitism, with higher trees increasing the parasitism odds ratio. The "nest exposure" hypothesis was also supported since parasitized nests had a shorter stand of vegetation in the close vicinity than non-parasitized nests. However, visibility of the nest from the nearest potential cuckoo perch (cuckoo view) was not selected by the model, probably because most nests were well concealed. Laying date, height of nest above ground and the distance from the nest to the nearest edge of the vegetation were not important predictors of parasitism. Though smaller nests tended to be parasitized more frequently than larger ones, nest size only approached significance, making its importance unclear.     

To eject or to abandon? Life history traits of hosts and parasites interact to influence the fitness payoffs of alternative anti‐parasite strategies

Hosts either tolerate avian brood parasitism or reject it by ejecting parasitic eggs, as seen in most rejecter hosts of common cuckoos, Cuculus canorus, or by abandoning parasitized clutches, as seen in most rejecter hosts of brown‐headed cowbirds, Molothrus ater. What explains consistent variation between alternative rejection behaviours of hosts within the same species and across species when exposed to different types of parasites? Life history theory predicts that when parasites decrease the fitness of host offspring, but not the future reproductive success of host adults, optimal clutch size should decrease. Consistent with this prediction, evolutionarily old cowbird hosts, but not cuckoo hosts, have lower clutch sizes than related rarely‐ or newly parasitized species. We constructed a mathematical model to calculate the fitness payoffs of egg ejector vs. nest abandoner hosts to determine if various aspects of host life history traits and brood parasites’ virulence on adult and young host fitness differentially influence the payoffs of alternative host defences. These calculations showed that in general egg ejection was a superior anti‐parasite strategy to nest abandonment. Yet, increasing parasitism rates and increasing fitness values of hosts’ eggs in both currently parasitized and future replacement nests led to switch points in fitness payoffs in favour of nest abandonment. Nonetheless, nest abandonment became selectively more favourable only at lower clutch sizes and only when hosts faced parasitism by a cowbird‐ rather than a cuckoo‐type brood parasite. We suggest that, in addition to evolutionary lag and gape‐size limitation, our estimated fitness differences based on life history trait variation provide new insights for the consistent differences observed in the anti‐parasite rejection strategies between many cuckoo‐ and cowbird‐hosts.     

Breeding success of common cuckoos Cuculus canorus parasitising four sympatric species of Acrocephalus warblers

We investigated the level of parasitism, egg mimicry and breeding success of cuckoos parasitising four sympatric species of Acrocephalus warblers in southern Moravia, Czech Republic. The parasitism rate was highest in the marsh warbler Acrocephalus palustris (44.8%) followed by great reed warbler A. arundinaceus (33.8%), sedge warbler A. schoenobaenus (26.5%) and reed warbler A. scirpaceus (11.6%). Although the cuckoo eggs showed a high level of mimicry the eggs of the marsh warbler this host species rejected 72% of the cuckoo eggs, resulting in a cuckoo breeding success of only 4.3%. Cuckoo eggs laid in great reed warbler and reed warbler nests showed a similar hatching success, but the cuckoo chicks survived better in great reed warbler nests, resulting in a breeding success of 30.4%, as compared to 16.4% in nests of the reed warbler. The relationship between the level of parasitism, host rejection of cuckoo eggs, cuckoo chick survival and breeding success is discussed for the four host species.     

A laboratory study of host use by the cuckoo catfish <Emphasis Type="Italic">Synodontis multipunctatus</Emphasis>

The only known non-avian vertebrate obligate brood parasite is the cuckoo catfish (Synodontis multipunctatus), a Lake Tanganyikan endemic. The cuckoo catfish parasitizes Tanganyikan mouthbrooding cichlids, and under captive conditions, will also parasitize cichlids from other Rift Valley lakes. Here we examine the frequency of parasitism by the cuckoo catfish of Ctenochromis horei from Lake Tanganyika and three species from Lake Malawi and the greater Lake Victorian system in a laboratory setting. C. horei was parasitized significantly less (17%) than the allopatric species Haplochromis latifasciatus, Haplochromis nubilus, and Metriaclima estherae (combined parasitism rate of 28%). The lower rates of parasitism in C. horei may be due to differences in the mating ritual, oviposition (e.g., long periods of pseudo-spawning before actual oviposition), and behavioral adaptations (e.g., increased aggression towards the cuckoo catfish). The number of catfish eggs per parasitized brood was similar between C. horei, H. latifasciatus, H. nubilus, and M. estherae. Our results are comparable to findings from the field for C. horei parasitism frequency and number of cuckoo catfish per brood. We also analyzed the parasitism rate of the albino morph of Metriaclima zebra, a domestic strain. Parasitism rates and number of catfish per brood were the highest in the albino morphotype suggesting that the higher levels of parasitism may be related to lower aggressive behavior, lower visual acuity, or captive influence. Cuckoo catfish and mouthbrooding cichlids provide a model system for testing brood parasitism in a laboratory setting.