Background: Birdsong is an important form of communication that plays an important role in territorial defense and mate attraction by conveying valuable information. While body-size and song frequency are often negati...Background: Birdsong is an important form of communication that plays an important role in territorial defense and mate attraction by conveying valuable information. While body-size and song frequency are often negatively correlated among species, this relationship is only found in a few songbirds. Previous studies on the Dusky Warbler (Phylloscopus fuscatus) found that there was a positive correlation between tarsus length and peak frequency. And heavier male Dusky Warblers possess better territories and obtain more opportunities for mating;body condition may be related to reproduction of birds, so females may choose heavier mates or better body condition based on the singing characteristics of males. Methods: We recorded spontaneous song and measured morphology of 33 male Dusky Warblers in Saihanba Forest Farm area between July 5 and August 10, 2015. We chose body weight as an indicator of body size and defined body condition as residuals from a linear regression between body weight and tarsus length. Frist, we used Pearson correlation to analyze whether date and time of day were correlated with weight, and then we used linear regression to analyze whether sound features could indicate the body weight and body condition. We call body weight and body condition the male condition. Results: We found no effect of date and time of day on weight, and we showed a correlation between the male condition and song features in the small songbird, Dusky Warbler. Maximum trill quality and maximum peak frequency of songs were negatively related to male condition;the mean number of syllables of songs and maximum high frequency of songs were positively correlated with body weight and body condition. Conclusions: In the small songbird, Dusky Warbler, four song parameters, including maximum trill quality, mean number of syllables of songs, maximum peak frequency of songs, maximum high frequency of songs, significantly predicted male condition change of which the most important song characteristic for male condition was maximum trill quality. This study suggested that the extreme song features were more constrained by male condition than mean sound characteristics.展开更多
The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra repro...The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra reproductive costs,they may be less willing to care for nestlings that have prolonged nestling periods.To test this hypothesis,the duration of feeding by Oriental Reed Warblers under natural conditions for their own nestlings was compared with the duration of feeding under natural conditions for Common Cuckoo nestlings and for artificially prolonged cuckoo nestlings.The results showed that Oriental Reed Warblers did not starve,drive away,or desert any of the nestlings in the experiment,and neither parent was left alone.Our experimental study indicates that both Oriental Reed Warbler parents were willing to care for nestlings with a prolonged nestling period(up to 30 days,twice the average duration time that the Oriental Reed Warblers fed their own chicks in natural conditions).However,further experiments and observations are required in other host bird species to examine whether both parents or one of the parents may exhibit the behavior of abandoning nestlings with a prolonged nestling period.展开更多
Our current understanding of how species have evolved is mainly based on comparative phylogenetic methods,which use phylogenies to infer the evolution of traits.The development of ancestral state reconstruction(ASR)me...Our current understanding of how species have evolved is mainly based on comparative phylogenetic methods,which use phylogenies to infer the evolution of traits.The development of ancestral state reconstruction(ASR)methods has provided the tools to reconstruct trait evolution,which are widely used in fields like evolutionary biology,macroecology and paleontology.As there are different elements involved in those analyses,with different levels of uncertainty(i.e.relating to branch length estimation,trait coding,statistical framework,taxon sampling or software),the various combinations of these elements likely have a strong impact on the reconstruction of the evolution of traits,potentially leading to opposite conclusions.To assess the impact of these different elements in ASR,we performed a set of analyses,including all possible combinations of such elements and using the evolution of migratory behavior in Sylvia warblers as a case study,which was coded as a continuous or as a discrete character.Our results show that taxon sampling,character coding,tree shape,statistical framework and software all significantly affect ASR,both individually and in combination.Not all reconstructed tree nodes show discrepancies,but in the critical ones most pairwise comparisons between analyses lead to conflicting and unexpectedly antagonistic results(zero migration vs fully migratory),thus challenging interpretations of trait evolution.We propose some possible solutions to partly inform decisions,involving the method selection and the incorporation of biological or fossil evidence regarding how traits evolve,but our results demand serious rethinking about how the research community currently uses ASR.展开更多
Avian alarm calls mediate defenses against brood parasites and predators. These calls facilitate communication among adults and alert nestlings to potential danger. While heterospecific call recognition has been exten...Avian alarm calls mediate defenses against brood parasites and predators. These calls facilitate communication among adults and alert nestlings to potential danger. While heterospecific call recognition has been extensively studied in adult birds, nestlings—lacking direct predation experience and heterospecific alarm exposure—represent an ideal system to investigate the response to interspecific warning cues. This study explored the recognition capabilities of 5–6-day-old nestlings in Oriental Reed Warbler (Acrocephalus orientalis), a common host of the Common Cuckoo (Cuculus canorus). We exposed the nestlings to playbacks of alarm calls directed at parasites and raptors from conspecific, Vinous-throated Parrotbill (Sinosuthora webbiana, sympatric species), Isabelline Shrike (Lanius isabellinus, allopatric species) and Common Tailorbird (Orthotomus sutorius, allopatric species) adults. Results indicated that there was no significant difference in the responses of nestlings to the alarm calls of conspecific and allopatric adults directed at cuckoos and sparrowhawks. In addition, interestingly, nestlings significantly reduced their begging in response to conspecific and unfamiliar allopatric Isabelline Shrike and Common Tailorbird alarm calls but exhibited a weak response to the sympatric Vinous-throated Parrotbill. Whether older warbler nestlings with more social experience exhibit stronger responses to the alarm calls of Vinous-throated Parrotbill adults requires further investigation.展开更多
Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness...Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.展开更多
Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that...Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that closely match the incubation stage of their own eggs.While intuitive,and supported by the findings of numerous longterm monitoring studies,experimental evidence of this remains sparse.By using video monitoring,we used three experimental groups to explore whether Common Cuckoos preferentially choose host Oriental Reed Warbler(Acrocephalus orientalis)nests that are early in their laying cycle.We found that Common Cuckoos preferentially parasitize nests of the host Oriental Reed Warbler that are earlier in their laying(less vs.more eggs)or nesting cycle(eggs vs.chicks),and videos of our experiments provide direct insights into their decision making process.Our results provide strong experimental evidence that Common Cuckoos are able to assess nesting stage and strategically choose nests that increase the likelihood of successful parasitism.展开更多
Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the hos...Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the host. In this study, we investigated how egg-spot matching between the Common Cuckoo(Cuculus canorus) and its host, the Oriental Reed Warbler(Acrocephalus orientalis) is affected by the local parasitism rate, nest availability in breeding synchronization and egg rejection.Methods: We used the paired design of parasitized and their nearest non-parasitized nests where breeding occurred simultaneously to compare egg-spot matching. The image analysis was used to compare four eggshell pattern variables, namely spot size, density, coverage on the different areas of egg surface, and the distribution on the whole egg surface. Egg recognition experiments were conducted to test the effect of egg spots on egg rejection by the host.Results: Our results show that much better matching in almost all spot parameters tested on the side of the egg and the spot distribution on the whole egg occurred in parasitized nests than in non-parasitized nests. Matching of spot density between cuckoo and host eggs in parasitized nests increased with the synchronization between temporal availability of nests and the egg-laying period of female cuckoos. Egg recognition experiments in which the warbler eggs were deliberately painted with extra spots led to a significantly higher egg rejection rate(78.3%) than of unpainted eggs.Conclusion: Our data suggest that both the high temporal encounter rate between cuckoo and warbler nests as well as the high egg rejection ability of the host are important factors for egg-spot matching of the cuckoos.展开更多
Moustached Warbler （Acrocephalus melanopogon）, belonging to the genus of Acrocephalus and the family of Acrocephalidae, breeds widely but locally in the warm temperate regions from Northwest Africa and eastern Iberi...Moustached Warbler （Acrocephalus melanopogon）, belonging to the genus of Acrocephalus and the family of Acrocephalidae, breeds widely but locally in the warm temperate regions from Northwest Africa and eastern Iberian Peninsula to eastern Kazakhstan. However, this species has never been scientifically recorded in China. On 22 April 2016, a Moustached Warbler was observed in Ulanbuy wetland （43°36′N, 87°43′E; 1114 m a.s.l.）, Urumqi, Xinjiang of China. This was the first photography-confirmed record of Moustached Warbler in China. As Moustached Warbler is a songbird, the songs were then recorded on 18 May 2016 using a Sony PCM D-100 recorder and the song characteristics were analyzed using Avisoft-SASLab software. The result showed that the mean maximum frequency of song strophes was 6.64 （±0.47） kHz and the mean minimum frequency of song strophes was 1.72 （±0.14） kHz. This study could considered as a supplement of the checklist of birds in China.展开更多
The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- ito...The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- itored 66 Marsh Grassbird nests during 2004-2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We ad- vocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increas- ing water levels during the breeding period （May-July） of Marsh Grassbirds.展开更多
Avian interspecific brood parasitism is an excellent system for studying coevolutionary processes in nature because brood parasites directly affect host reproductive success.Most research on avian brood parasitism has...Avian interspecific brood parasitism is an excellent system for studying coevolutionary processes in nature because brood parasites directly affect host reproductive success.Most research on avian brood parasitism has,therefore,focused primarily on specific host anti-parasite behaviours and parasite counter-adaptations.However,the population-level consequences of brood parasitism for host species are poorly understood.This study investigated the effect of Common Cuckoo(Cuculus canorus)parasitism on the productivity of a local population of the Great Reed Warbler(Acrocephalus arundinaceus)host in south-western Slovakia.A total of 495 females nesting at the studied site successfully fledged 1321 of their own young and 63 young of the Common Cuckoo over the course of 15 years(2008-2022),and the annual rate of successful parasitism ranged from 18% to 44% over this period.As predicted,higher rates of successful cuckoo parasitism significantly reduced the annual productivity of the local Great Reed Warbler population,and its contribution to decreased host reproductive success was at about the same rate as overall nest failure caused by predation and other environmental factors.Such a heavily parasitized population was probably maintained by immigrants from other populations and density-dependent selection,which is also consistent with source-sink dynamics.However,further long-term studies monitoring parasitized populations are required to confirm these findings.展开更多
Background: Soft song is a low-amplitude song produced by many birds. Recent studies have confirmed that soft song is an aggressive signal. For example, the Brownish-flanked Bush Warblers Cettia fortipes use soft song...Background: Soft song is a low-amplitude song produced by many birds. Recent studies have confirmed that soft song is an aggressive signal. For example, the Brownish-flanked Bush Warblers Cettia fortipes use soft song in male-male conflicts, particularly prior to attacks. Although stable signaling systems require that signals be honest on average,models predict that cheating is an acceptable strategy for some individuals or in some contexts.Methods: This study aimed to test the reliability of soft song as an aggressive signal in the brownish-flanked bush warbler. We used mounted specimens accompanied by broadcast songs or soft songs to simulate a male attempting to invade an existing territory.Results: We found the mounted specimen that coupled playback of soft songs suffered more and quicker attacks from the territory owner and that the relationship between soft song and subsequent attack in the territory owner was far from perfect. We observed territory owners that both over-signaled(i.e., produced soft song but did not attack) and under-signaled(i.e., attacked without producing soft song). Under-signaling territory owners were relatively more commonly than were over-signaling territory owners, particularly in simulated intrusion that coupled playback of soft song with a mount specimen.Conclusions: We discuss the cost of producing soft song and the potential benefit of the unreliable use of soft song and propose a new hypothesis for under-signaling with soft song; i.e., under-signaling territory owners might benefit from taking the initiative in fights.展开更多
Background:As one of the most elaborate and diverse sexual signals,bird songs are prominent among mate choice criteria.Females generally prefer mates with larger repertoire size,which promotes the evolution of song co...Background:As one of the most elaborate and diverse sexual signals,bird songs are prominent among mate choice criteria.Females generally prefer mates with larger repertoire size,which promotes the evolution of song complex?ity.However,there are also some songbirds that have far simpler and less diverse vocalizations,which have not been the focus of scientific scrutiny.Most Phylloscopus warblers are accomplished singers with complex songs.In contrast,Hume's Warbler(P.humei) has extremely simple songs.In order to explore the song's function,its evolutionary sig?nificance and particularly to assess its possible relationship with parental investment,we studied mate choice of the subspecies P.h.mandellii in Lianhuashan National Nature Reserve,Gansu,China.Methods:We recorded body measurements and songs of breeding males and then explored their relationships with the date of clutch initiation,reasoning that the characteristics of males that are involved with early nesting activities reflect female mate preferences.We also recorded egg size and body measurements of nestlings to assess the rela?tionship between parental investment and mate choice.Results:We found that male wing and tail lengths were positively correlated with early clutch initiation as were songs characterized by short duration and rapid rise to maximum amplitude.We also found that early?breeding females did not lay large eggs,but produced more surviving young,which grew up faster.Conclusions:Female mate choice criteria in this bird include both visual signals and song characteristics.Our study supports the hypothesis that females may judge male quality from quite subtle differences.In order to reduce the risk of predation,a preference for such inconspicuous male characteristics may be partially driven by high vulnerability of this warbler to predators as a ground?nesting species.展开更多
Avian brood parasitism constitutes a classical model for studying coevolution.The discovery and reporting of cuckoo parasitism on various new hosts contribute to a deeper comprehension of the coevolutionary relationsh...Avian brood parasitism constitutes a classical model for studying coevolution.The discovery and reporting of cuckoo parasitism on various new hosts contribute to a deeper comprehension of the coevolutionary relationships between these parasites and their hosts.This study involved field monitoring of the black-browed reed warbler(Acrocephalus bistrigiceps,BRW)in a reed wetland of northeast China during the breeding seasons for 13 consecutive years(2012-2024).A total of 677 BRW nests were monitored,and only three cases of cuckoo parasitism were detected,for a parasitism rate of 0.44%.An egg recognition experiment indicated that the BRW possesses a relatively strong egg recognition ability and can effectively reject foreign parasitic eggs.The color characteristics of common cuckoo and BRW eggs are considerably different.Through the analysis and comparison of egg color spectra between cuckoo and warbler eggs,combined with the field cuckoo parasitism rate and egg recognition ability of warblers,we concluded that the BRW is not a commonly used host for the common cuckoo.展开更多
基金funded by the Natural Science Foundation of Hebei Province(No.C2012204087)the Natural Science Research Plan Project of Hebei University(No.2014-299)
文摘Background: Birdsong is an important form of communication that plays an important role in territorial defense and mate attraction by conveying valuable information. While body-size and song frequency are often negatively correlated among species, this relationship is only found in a few songbirds. Previous studies on the Dusky Warbler (Phylloscopus fuscatus) found that there was a positive correlation between tarsus length and peak frequency. And heavier male Dusky Warblers possess better territories and obtain more opportunities for mating;body condition may be related to reproduction of birds, so females may choose heavier mates or better body condition based on the singing characteristics of males. Methods: We recorded spontaneous song and measured morphology of 33 male Dusky Warblers in Saihanba Forest Farm area between July 5 and August 10, 2015. We chose body weight as an indicator of body size and defined body condition as residuals from a linear regression between body weight and tarsus length. Frist, we used Pearson correlation to analyze whether date and time of day were correlated with weight, and then we used linear regression to analyze whether sound features could indicate the body weight and body condition. We call body weight and body condition the male condition. Results: We found no effect of date and time of day on weight, and we showed a correlation between the male condition and song features in the small songbird, Dusky Warbler. Maximum trill quality and maximum peak frequency of songs were negatively related to male condition;the mean number of syllables of songs and maximum high frequency of songs were positively correlated with body weight and body condition. Conclusions: In the small songbird, Dusky Warbler, four song parameters, including maximum trill quality, mean number of syllables of songs, maximum peak frequency of songs, maximum high frequency of songs, significantly predicted male condition change of which the most important song characteristic for male condition was maximum trill quality. This study suggested that the extreme song features were more constrained by male condition than mean sound characteristics.
基金supported by the National Natural Science Foundation of China(Nos.32270526 to WL,32260253 to LW and 32101242 to LM)。
文摘The Oriental Reed Warbler(Acrocephalus orientalis)is one of the most commonly used hosts for the parasitic Common Cuckoo(Cuculus canorus).However,as hosts that feed unrelated parasitic nestlings may suffer extra reproductive costs,they may be less willing to care for nestlings that have prolonged nestling periods.To test this hypothesis,the duration of feeding by Oriental Reed Warblers under natural conditions for their own nestlings was compared with the duration of feeding under natural conditions for Common Cuckoo nestlings and for artificially prolonged cuckoo nestlings.The results showed that Oriental Reed Warblers did not starve,drive away,or desert any of the nestlings in the experiment,and neither parent was left alone.Our experimental study indicates that both Oriental Reed Warbler parents were willing to care for nestlings with a prolonged nestling period(up to 30 days,twice the average duration time that the Oriental Reed Warblers fed their own chicks in natural conditions).However,further experiments and observations are required in other host bird species to examine whether both parents or one of the parents may exhibit the behavior of abandoning nestlings with a prolonged nestling period.
基金This work was supported by a grant of the Spanish Ministerio de Economía y Competitividad and FEDER CGL2013-40924-P,CGL2017-89898-R(AEI/FEDER,UE)a BiodivERsA:EC21C ERANet grant to DRV.RP was supported by an FPU predoctoral fellowship from the Spanish Ministerio de Educación.
文摘Our current understanding of how species have evolved is mainly based on comparative phylogenetic methods,which use phylogenies to infer the evolution of traits.The development of ancestral state reconstruction(ASR)methods has provided the tools to reconstruct trait evolution,which are widely used in fields like evolutionary biology,macroecology and paleontology.As there are different elements involved in those analyses,with different levels of uncertainty(i.e.relating to branch length estimation,trait coding,statistical framework,taxon sampling or software),the various combinations of these elements likely have a strong impact on the reconstruction of the evolution of traits,potentially leading to opposite conclusions.To assess the impact of these different elements in ASR,we performed a set of analyses,including all possible combinations of such elements and using the evolution of migratory behavior in Sylvia warblers as a case study,which was coded as a continuous or as a discrete character.Our results show that taxon sampling,character coding,tree shape,statistical framework and software all significantly affect ASR,both individually and in combination.Not all reconstructed tree nodes show discrepancies,but in the critical ones most pairwise comparisons between analyses lead to conflicting and unexpectedly antagonistic results(zero migration vs fully migratory),thus challenging interpretations of trait evolution.We propose some possible solutions to partly inform decisions,involving the method selection and the incorporation of biological or fossil evidence regarding how traits evolve,but our results demand serious rethinking about how the research community currently uses ASR.
基金funded by the National Natural Science Foundation of China (No. 32301295 to JW, 32101242 to LM, and 32260253 to LW)High-Level Talents Research Start-Up Project of Hebei University (No. 521100222044 to JW)
文摘Avian alarm calls mediate defenses against brood parasites and predators. These calls facilitate communication among adults and alert nestlings to potential danger. While heterospecific call recognition has been extensively studied in adult birds, nestlings—lacking direct predation experience and heterospecific alarm exposure—represent an ideal system to investigate the response to interspecific warning cues. This study explored the recognition capabilities of 5–6-day-old nestlings in Oriental Reed Warbler (Acrocephalus orientalis), a common host of the Common Cuckoo (Cuculus canorus). We exposed the nestlings to playbacks of alarm calls directed at parasites and raptors from conspecific, Vinous-throated Parrotbill (Sinosuthora webbiana, sympatric species), Isabelline Shrike (Lanius isabellinus, allopatric species) and Common Tailorbird (Orthotomus sutorius, allopatric species) adults. Results indicated that there was no significant difference in the responses of nestlings to the alarm calls of conspecific and allopatric adults directed at cuckoos and sparrowhawks. In addition, interestingly, nestlings significantly reduced their begging in response to conspecific and unfamiliar allopatric Isabelline Shrike and Common Tailorbird alarm calls but exhibited a weak response to the sympatric Vinous-throated Parrotbill. Whether older warbler nestlings with more social experience exhibit stronger responses to the alarm calls of Vinous-throated Parrotbill adults requires further investigation.
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background: Resemblance to raptors such as hawks(Accipiter spp.) is considered to be an adaptive strategy of cuckoos(Cuculus spp.), which has evolved to protect cuckoos against host attacks. However, the effectiveness of the mimicry remains controversial, and is not yet fully studied for highly aggressive hosts.Methods: We evaluated the effectiveness of sparrowhawk(Accipiter nisus) mimicry by common cuckoos(Cuculus canorus) in oriental reed warblers(Acrocephaus orientalis), which are highly aggressive hosts. Using a both the single and the paired dummy experiment, defense behaviors and attack intensities of oriental reed warblers against common cuckoos, sparrowhawks and oriental turtle doves(Streptopelia orientalis) were assessed.Results: Oriental reed warblers exhibit strong nest defense behaviors, and such behaviors do not change with breeding stage(i.e., egg stage and nestling stage). Furthermore, assistance from conspecific helpers may increase attack intensities. However, they were deterred from mobbing overall by the presence of the hawk.Conclusions: Oriental reed warblers are able to distinguish cuckoos from harmless doves. However, they may be deterred from mobbing by the presence of the predatory hawk, suggesting hawk mimicry may be ineffective and does not reduce attacks of cuckoos by highly aggressive hosts.
基金supported by the National Natural Science Foundation of China(Nos.31960105 to LW,and 31970427 to WL)the specific research fund of the Innovation Platform for Academicians of Hainan Provincefunded by the Guizhou Natural Science Foundation(No.ZK[2022]-316)。
文摘Brood parasites,such as the Common Cuckoo(Cuculus canorus),rely on manipulating hosts from other species to raise their offspring.Selection should favor individuals that are able to identify and choose host nests that closely match the incubation stage of their own eggs.While intuitive,and supported by the findings of numerous longterm monitoring studies,experimental evidence of this remains sparse.By using video monitoring,we used three experimental groups to explore whether Common Cuckoos preferentially choose host Oriental Reed Warbler(Acrocephalus orientalis)nests that are early in their laying cycle.We found that Common Cuckoos preferentially parasitize nests of the host Oriental Reed Warbler that are earlier in their laying(less vs.more eggs)or nesting cycle(eggs vs.chicks),and videos of our experiments provide direct insights into their decision making process.Our results provide strong experimental evidence that Common Cuckoos are able to assess nesting stage and strategically choose nests that increase the likelihood of successful parasitism.
基金supported by the National Natural Science Foundation of China (Nos.31301888 and 31672316 to DL)the General Scientific Research Project of the Education Department of Liaoning Province (L2015196 to DL)the Open Fund of the Ministry of Education Key Laboratory for Biodiversity Sciences and Ecological Engineering, Beijing Normal University (K1401 to DL)
文摘Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the host. In this study, we investigated how egg-spot matching between the Common Cuckoo(Cuculus canorus) and its host, the Oriental Reed Warbler(Acrocephalus orientalis) is affected by the local parasitism rate, nest availability in breeding synchronization and egg rejection.Methods: We used the paired design of parasitized and their nearest non-parasitized nests where breeding occurred simultaneously to compare egg-spot matching. The image analysis was used to compare four eggshell pattern variables, namely spot size, density, coverage on the different areas of egg surface, and the distribution on the whole egg surface. Egg recognition experiments were conducted to test the effect of egg spots on egg rejection by the host.Results: Our results show that much better matching in almost all spot parameters tested on the side of the egg and the spot distribution on the whole egg occurred in parasitized nests than in non-parasitized nests. Matching of spot density between cuckoo and host eggs in parasitized nests increased with the synchronization between temporal availability of nests and the egg-laying period of female cuckoos. Egg recognition experiments in which the warbler eggs were deliberately painted with extra spots led to a significantly higher egg rejection rate(78.3%) than of unpainted eggs.Conclusion: Our data suggest that both the high temporal encounter rate between cuckoo and warbler nests as well as the high egg rejection ability of the host are important factors for egg-spot matching of the cuckoos.
基金supported by the Investigation of Terrestrial Wildlife Resources in the Zoogeographic Unit of North Slopes of the Tianshan Mountains,Xinjiang,China(XJLK2014009)the Second Wetland Resource Survey of Xinjiang Uygur Autonomous Region(XJLK2011008)the National Key Research and Development Programme(2016YFC1200700)
文摘Moustached Warbler （Acrocephalus melanopogon）, belonging to the genus of Acrocephalus and the family of Acrocephalidae, breeds widely but locally in the warm temperate regions from Northwest Africa and eastern Iberian Peninsula to eastern Kazakhstan. However, this species has never been scientifically recorded in China. On 22 April 2016, a Moustached Warbler was observed in Ulanbuy wetland （43°36′N, 87°43′E; 1114 m a.s.l.）, Urumqi, Xinjiang of China. This was the first photography-confirmed record of Moustached Warbler in China. As Moustached Warbler is a songbird, the songs were then recorded on 18 May 2016 using a Sony PCM D-100 recorder and the song characteristics were analyzed using Avisoft-SASLab software. The result showed that the mean maximum frequency of song strophes was 6.64 （±0.47） kHz and the mean minimum frequency of song strophes was 1.72 （±0.14） kHz. This study could considered as a supplement of the checklist of birds in China.
基金supported by the National Natural Science Foundation of China(Grant No.3037022141310302+1 种基金41001026)the Fundamental Research Funds for the Central Universities of China(Grant No.DL12CA09)
文摘The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest- site selection can minimize nest loss, especially for open- cup and ground nesting passerines. We located and mon- itored 66 Marsh Grassbird nests during 2004-2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We ad- vocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increas- ing water levels during the breeding period （May-July） of Marsh Grassbirds.
文摘Avian interspecific brood parasitism is an excellent system for studying coevolutionary processes in nature because brood parasites directly affect host reproductive success.Most research on avian brood parasitism has,therefore,focused primarily on specific host anti-parasite behaviours and parasite counter-adaptations.However,the population-level consequences of brood parasitism for host species are poorly understood.This study investigated the effect of Common Cuckoo(Cuculus canorus)parasitism on the productivity of a local population of the Great Reed Warbler(Acrocephalus arundinaceus)host in south-western Slovakia.A total of 495 females nesting at the studied site successfully fledged 1321 of their own young and 63 young of the Common Cuckoo over the course of 15 years(2008-2022),and the annual rate of successful parasitism ranged from 18% to 44% over this period.As predicted,higher rates of successful cuckoo parasitism significantly reduced the annual productivity of the local Great Reed Warbler population,and its contribution to decreased host reproductive success was at about the same rate as overall nest failure caused by predation and other environmental factors.Such a heavily parasitized population was probably maintained by immigrants from other populations and density-dependent selection,which is also consistent with source-sink dynamics.However,further long-term studies monitoring parasitized populations are required to confirm these findings.
基金supported by National Natural Science Foundation of China (No.31172098)the China Postdoctoral Science Foundation (No.2014 M550026)
文摘Background: Soft song is a low-amplitude song produced by many birds. Recent studies have confirmed that soft song is an aggressive signal. For example, the Brownish-flanked Bush Warblers Cettia fortipes use soft song in male-male conflicts, particularly prior to attacks. Although stable signaling systems require that signals be honest on average,models predict that cheating is an acceptable strategy for some individuals or in some contexts.Methods: This study aimed to test the reliability of soft song as an aggressive signal in the brownish-flanked bush warbler. We used mounted specimens accompanied by broadcast songs or soft songs to simulate a male attempting to invade an existing territory.Results: We found the mounted specimen that coupled playback of soft songs suffered more and quicker attacks from the territory owner and that the relationship between soft song and subsequent attack in the territory owner was far from perfect. We observed territory owners that both over-signaled(i.e., produced soft song but did not attack) and under-signaled(i.e., attacked without producing soft song). Under-signaling territory owners were relatively more commonly than were over-signaling territory owners, particularly in simulated intrusion that coupled playback of soft song with a mount specimen.Conclusions: We discuss the cost of producing soft song and the potential benefit of the unreliable use of soft song and propose a new hypothesis for under-signaling with soft song; i.e., under-signaling territory owners might benefit from taking the initiative in fights.
基金supported by the National Natural Sciences Foundation of China(Grant Nos.31301886,31272286)
文摘Background:As one of the most elaborate and diverse sexual signals,bird songs are prominent among mate choice criteria.Females generally prefer mates with larger repertoire size,which promotes the evolution of song complex?ity.However,there are also some songbirds that have far simpler and less diverse vocalizations,which have not been the focus of scientific scrutiny.Most Phylloscopus warblers are accomplished singers with complex songs.In contrast,Hume's Warbler(P.humei) has extremely simple songs.In order to explore the song's function,its evolutionary sig?nificance and particularly to assess its possible relationship with parental investment,we studied mate choice of the subspecies P.h.mandellii in Lianhuashan National Nature Reserve,Gansu,China.Methods:We recorded body measurements and songs of breeding males and then explored their relationships with the date of clutch initiation,reasoning that the characteristics of males that are involved with early nesting activities reflect female mate preferences.We also recorded egg size and body measurements of nestlings to assess the rela?tionship between parental investment and mate choice.Results:We found that male wing and tail lengths were positively correlated with early clutch initiation as were songs characterized by short duration and rapid rise to maximum amplitude.We also found that early?breeding females did not lay large eggs,but produced more surviving young,which grew up faster.Conclusions:Female mate choice criteria in this bird include both visual signals and song characteristics.Our study supports the hypothesis that females may judge male quality from quite subtle differences.In order to reduce the risk of predation,a preference for such inconspicuous male characteristics may be partially driven by high vulnerability of this warbler to predators as a ground?nesting species.
基金The National Natural Science Foundation of China(32260253)The Guizhou Natural Science Foundation(ZK[2022]-316)。
文摘Avian brood parasitism constitutes a classical model for studying coevolution.The discovery and reporting of cuckoo parasitism on various new hosts contribute to a deeper comprehension of the coevolutionary relationships between these parasites and their hosts.This study involved field monitoring of the black-browed reed warbler(Acrocephalus bistrigiceps,BRW)in a reed wetland of northeast China during the breeding seasons for 13 consecutive years(2012-2024).A total of 677 BRW nests were monitored,and only three cases of cuckoo parasitism were detected,for a parasitism rate of 0.44%.An egg recognition experiment indicated that the BRW possesses a relatively strong egg recognition ability and can effectively reject foreign parasitic eggs.The color characteristics of common cuckoo and BRW eggs are considerably different.Through the analysis and comparison of egg color spectra between cuckoo and warbler eggs,combined with the field cuckoo parasitism rate and egg recognition ability of warblers,we concluded that the BRW is not a commonly used host for the common cuckoo.
