Chalcites Lucidus Research Articles

Post-mortem examinations of New Zealand birds. 3. Shining cuckoos (Chrysococcyx lucidus Aves: Cuculinae)

ABSTRACT I examined 107 shining cuckoos that died accidentally in the northern North Island, New Zealand, during 39 years. Birds arriving on migration in spring were all in adult plumage. Juveniles occurred mainly from January to March. The sex-ratio of adults was 1:1. In several measurements, females were slightly larger than males on average, and adults slightly larger than juveniles. Gonad size suggested readiness for breeding from September to January (inclusive). Ninety-one gizzards held a total of 3754 arthropod food items. Insects (10 orders) made up around 94% of items and just two orders accounted for 79% of food items: caterpillars (larval Lepidoptera, 55%) and beetles (Coleoptera, 24%). ‘Spiny’ caterpillars made up roughly 8% of total caterpillars. Ladybirds (Coccinellidae) made up 21% of beetles. Shining cuckoos ate small prey, mostly 1–10 mm long (44%) and 11–20 mm long (43%). By eating hairy caterpillars and ladybirds, shining cuckoos exert predatory control on insects that other birds avoid. By gorging (up to 258 insects per stomach) the cuckoo might dampen the impact of herbivorous insects (e.g. caterpillar infestations) on plants.

Polymorphism at the nestling stage and host-specific mimicry in an Australasian cuckoo-host arms race.

Decades of research have shown that the coevolutionary arms race between avian brood parasites and their hosts can promote phenotypic diversification in hosts and brood parasites. However, relatively little is known about the role of brood parasitism in promoting phenotypic diversification of nestlings. We review field data collected over four decades in Australia, New Caledonia and New Zealand to assess potential for coevolutionary interactions between the shining bronze-cuckoo (Chalcites lucidus) and its hosts, and how diversification at the nestling stage may be generating different subspecies. The shining bronze-cuckoo is a specialist parasite of a few hosts in the family Acanthizidae. It has diversified into subspecies, of which the nestlings closely mimic the respective host nestlings in each region. Additionally, some cuckoo subspecies have polymorphic nestlings. The Acanthizidae hosts have similar breeding and nesting habits and only moderately effective frontline defences against parasitism at cuckoo egg laying or at the egg stages. However, some hosts have developed highly effective defences at the nestling stage by recognising and ejecting cuckoo nestlings from the nest. As with the cuckoo nestlings, some hosts have polymorphic nestlings. The coevolutionary interactions in each region suggest different evolutionary stages of the arms race in which either the parasite or the host is currently in the lead. The presence of moderately effective defences at the egg laying and egg stages might explain why some hosts do not have defences at the nestling stage. The south-Pacific cuckoo - host systems are excellent models to explore the evolutionary mechanisms driving the diversification at the nestling stage in the coevolutionary arms race between avian brood parasites and their hosts.

Discrimination and ejection of eggs and nestlings by the fan-tailed gerygone from New Caledonia.

Nestling rejection is a rare type of host defense against brood parasitism compared with egg rejection. Theoretically, host defenses at both egg and nestling stages could be based on similar underlying discrimination mechanisms but, due to the rarity of nestling rejector hosts, few studies have actually tested this hypothesis. We investigated egg and nestling discrimination by the fan-tailed gerygone Gerygone flavolateralis, a host that seemingly accepts nonmimetic eggs of its parasite, the shining bronze-cuckoo Chalcites lucidus, but ejects mimetic parasite nestlings. We introduced artificial eggs or nestlings and foreign gerygone nestlings in gerygone nests and compared begging calls of parasite and host nestlings. We found that the gerygone ejected artificial eggs only if their size was smaller than the parasite or host eggs. Ejection of artificial nestlings did not depend on whether their color matched that of the brood. The frequency of ejection increased during the course of the breeding season mirroring the increase in ejection frequency of parasite nestlings by the host. Cross-fostered gerygone nestlings were frequently ejected when lacking natal down and when introduced in the nest before hatching of the foster brood, but only occasionally when they did not match the color of the foster brood. Begging calls differed significantly between parasite and host nestlings throughout the nestling period. Our results suggest that the fan-tailed gerygone accepts eggs within the size range of gerygone and cuckoo eggs and that nestling discrimination is based on auditory and visual cues other than skin color. This highlights the importance of using a combined approach to study discrimination mechanisms of hosts.

Threat recognition and response in an avian brood-parasite host from New Caledonia

AbstractNest predation and avian brood parasitism are the main sources of nest failure in many passerine birds. Large predators threaten both brood and parents, whereas brood parasites pose only a danger to eggs or nestlings. The fan-tailed gerygone Gerygone flavolateralis from New Caledonia is subjected to high rates of nest predation by the New Caledonian crow Corvus moneduloides (responsible for about 20–40% of predation) and moderate rates of brood parasitism by the shining bronze-cuckoo Chalcites lucidus (parasitizing about 18% of nests), which also depredates nests that are too advanced for parasitism (13% of nests). To test if fan-tailed gerygones are able to discriminate predators from brood parasites, we presented 3 bird models at active gerygone nests: a brood parasite/small nest predator (shining bronze-cuckoo), a large nest predator (crow), and a small non-native bird (common chaffinch Fringilla coelebs), which is unknown to the gerygone, as a control. We assessed the response of adult gerygones to the presentation of each model by measuring the minimum approach distance, number of alarm calls, number of attacks, and time to first nest visit after the presentation (latency). Adult gerygones often attacked the cuckoo, approached but never attacked the chaffinch and always avoided the crow. Latency was shorter after an attack response and during brooding, but similar among models. We did not find any link between the cuckoo model presentation and later ejection of cuckoo nestlings. We conclude that adult fan-tailed gerygones discriminate between different models and respond accordingly to the level of threat, but do not show awareness of parasitism risk and increase of nestling ejection rates following exposure to the cuckoo model.

Impact of brood parasitism and predation on nest survival of the fan‐tailed gerygone in New Caledonia

Predation and brood parasitism are common reasons for nesting failure in passerine species and the additive impact by invasive species is a major conservation concern, particularly on tropical islands. Recognising the relative contribution of the different components of nesting failure rates is important to understand co‐evolutionary interactions within brood parasite–host systems. In the remote archipelago of New Caledonia, the fan‐tailed gerygoneGerygone flavolateralisis the exclusive host of the brood‐parasitic shining bronze‐cuckooChalcites lucidus. Additionally, invasive rodents also possibly have an impact on breeding success. To estimate the impact of potential nest predators, we 1) video monitored nests to identify predators, 2) estimated the probability of predation based on nest visibility and predator abundance and 3) tested the possibility that the location of experimental nests and lack of odour cues decrease the predation by rodents. In addition, we estimated nest survival rates using data collected in different habitats over the course of eight breeding seasons. Nesting success of fan‐tailed gerygones was relatively low and predation was the main cause of nesting failure. We recorded mainly predation by native birds, including the shining bronze‐cuckoo, whereas predation by rats was rare. In open habitats predation by cuckoos was much lower than predation by other avian predators. Neither predator activity around nests nor nest visibility influenced the probability of predation. Experimental nests in more accessible locations and containing an odorous bait were more exposed to rodent predation. Apparently, the fan‐tailed gerygone has either never been specifically vulnerable to predation by rats or has developed anti‐predator adaptations.

Nest illumination and the evolution of egg rejection in hosts of brood parasites

ABSTRACT Hosts of avian brood parasites, such as cuckoos, are duped into taking care of a foreign chick and this has led to the evolution of host defenses, such as egg rejection. However, many host species are not egg rejecters and it has been suggested that poor illumination inside closed nests may constrain the evolution of this defense. In this study, we experimentally increased the light inside the dome nests of Yellow-Rumped Thornbills, the main host of the Shining Bronze-Cuckoo. Our results show that rejection events did not increase significantly when nests were brighter, although there is a possibility that rejection mistakes could decrease. Moreover, we found that natural light levels inside dome nests were highly variable, and in many cases as high as those in cup-nesting species with high rejection rates. This evidence suggests that rapid changes in nest illumination do not alter rejection behavior.

Breeding biology of the Fan-tailed Gerygone Gerygone flavolateralis in relation to parasitism by the Shining Bronze-cuckoo Chalcites lucidus

Apart from a few well-studied examples, there is little information regarding the life history and ecological requirements of brood parasites and their hosts in most cuckoo–host systems, particularly in tropical areas. In New Caledonia, the Fan-tailed Gerygone Gerygone flavolateralis, is the exclusive host of the Shining Bronze-cuckoo, Chalcites lucidus. Here, the arms race has escalated to the nestling stage, and both host and parasite have polymorphic (difference in skin coloration) nestlings. This is a novel system for the study of brood parasitism, but very little is known about the breeding biology of the Fan-tailed Gerygone and how this may affect the co-evolutionary interactions with the Shining Bronze-cuckoo. We monitored active nests of the Fan-tailed Gerygone during six breeding seasons, using video monitoring and direct observation. Nest attendance periods of host parents were shorter during laying than during incubation, and therefore parasitism was more likely to occur during the laying period. Cuckoos eggs were on average 2 days more developed than host eggs, and thus cuckoo nestlings usually hatched before host nestlings. Fan-tailed Gerygone nestling phenotypes had similar growth and fledging rates and their frequency did not differ between habitats, indicating no apparent trade-off with skin coloration. The precipitation regime affected predation but not the parasitism rate. The current situation in New Caledonia suggests a higher selection pressure on the parasite than on the host. Our study highlights the importance of data on the breeding biology of the host in the context of studies on brood parasitism.

Visual discrimination of polymorphic nestlings in a cuckoo-host system

Mimicry by avian brood parasites favours uniformity over variation within a breeding attempt as host defence against parasitism. In a cuckoo-host system from New Caledonia, the arms race resulted in both host (Gerygone flavolateralis) and parasite (Chalcites lucidus) having nestlings of two discrete skin colour phenotypes, bright and dark. In our study sites, host nestlings occurred in monomorphic and polymorphic broods, whereas cuckoo nestlings only occurred in the bright morph. Irrespective of their brood colour, host parents recognised and ejected parasite nestlings but never ejected their own. We investigated whether host parents visually recognised their own nestlings by using colour, luminance and pattern of multiple body regions. We found that the parasite mimicked multiple visual features of both host morphs and that the visual difference between host morphs was larger than the difference between the parasite and the mimicked host morph. Visual discrimination alone may result in higher chances of recognition errors in polymorphic than in monomorphic host broods. Host parents may rely on additional sensorial cues, not only visual, to assess nestling identity. Nestling polymorphism may be a trace of evolutionary past and may only have a marginal role in true-recognition of nestlings in the arms race in New Caledonia.

Grey Gerygone hosts are not egg rejecters, but Shining Bronze-Cuckoos lay cryptic eggs

ABSTRACT Many brood parasites rely on mimicry to prevent the detection of their eggs by hosts, yet most Australasian cuckoo species lay darkly colored eggs while the eggs of their hosts are pale and speckled. In the dimly lit nests of their hosts, these cuckoo eggs may appear cryptic; however, it is unclear if this disguise has evolved to fool hosts or other cuckoos. Recent work suggests that in at least one species of bronze-cuckoo, cuckoos are more likely to reject conspicuous eggs than are hosts, but it remains unclear whether this is common across the species group. Here, we present field experiments on the sole host of the Shining Bronze-Cuckoo (Chalcites lucidus lucidus) in New Zealand, the Grey Gerygone (Gerygone igata; known locally as the Grey Warbler), that explored whether this host ignores cuckoo eggs because they are cryptic. Using an avian vision model, we showed that Shining Bronze-Cuckoo eggs were variable in their conspicuousness, but were more cryptic in host nests than the host's eggs. ...

Batten down the thatches: front-line defences in an apparently defenceless cuckoo host

Avian brood parasites lay their eggs in the nests of other species, imposing high costs on their hosts. In theory, this should select for the evolution of defences against parasitism in hosts, yet eviction of parasite eggs or chicks is absent in many host species. One such host is the yellow-rumped thornbill, Acanthiza chrysorrhoa, the primary host of the shining bronze-cuckoo, Chalcites lucidus, in Australia. Here we tested whether the lack of egg and chick rejection in yellow-rumped thornbills has led to the evolution of alternative defences against brood parasitism. We provide evidence that this host has evolved two types of frontline defences. First, yellow-rumped thornbills responded to the presence of a cuckoo mount near the nest with mobbing behaviour and by occupying their dome-shaped nests, potentially as a means of blocking the small entrance hole. Second, we show that brood parasitism imposes directional selection for early breeding on the yellow-rumped thornbill and that yellow-rumped thornbills show a concomitant shift in their breeding phenology, breeding earlier than both congeneric and sympatric species. Our results highlight the importance of studying apparently defenceless hosts in order to identify alternative defence strategies.

Establishment of Microsatellite Markers to Assess the Mating System of the Fan-Tailed Gerygone (Gerygone flavolateralis) for Studying Cuckoo-Host Arms Race

We developed a set of microsatellite markers for the fan-tailed gerygone (Gerygone flavolateralis), host of a brood parasite, the shining bronze-cuckoo (Chalcites lucidus). We used 454 pyro-sequencing to establish 17 polymorphic microsatellite markers. The number of alleles per locus ranged from 6 to 18, the expected heterozygosity from 0.328 to 0.931 and the polymorphism information content from 0.306 to 0.916. The developed set of microsatellites will allow us to determine the gerygone's mating system, which is crucial to understand inheritance of dichromatism in skin colour of their chicks.

Latitudinal differences in the breeding phenology of Grey Warblers covary with the prevalence of parasitism by Shining Bronze-Cuckoos

Variation in the temporal patterns of nest availability through the breeding season or across the geographical range of a host is expected to be an important selection pressure shaping the breeding biology of avian brood parasites. The archipelago-wide distribution of the endemic Grey Warbler (Gerygone igata) in New Zealand, and its parasitism by the specialist Shining Bronze-Cuckoo (Chalcites lucidus), makes this a valuable system in which to study small-scale latitudinal gradients in host breeding phenology and the effects of these on the prevalence of brood parasitism. Nest records from throughout New Zealand and our study sites on both the North and South Islands indicated that, as expected, clutch-sizes were larger at higher, more southern, latitudes. Contrary to predictions, breeding began later and finished earlier, and usually involved only one brood on the North Island, compared with a longer breeding season with two broods on the South Island. Prevalence of brood parasitism covaried positively with latitude, suggesting that geographical patterns in breeding phenology of hosts may influence the prevalence of parasitism.

Predicted visual sensitivity for short-wavelength light in the brood parasitic cuckoos of New Zealand

Different lineages of birds show varying sensitivity to light in the ultraviolet (UV) wavelengths. In several avian brood parasite-host systems, UV-reflectance of the parasite eggs is important in discriminating own from foreign eggs by the hosts. In turn, for parasitic females it may be beneficial to lay eggs into host clutches where eggs more closely match the parasite's own eggs. While the visual sensitivities of numerous cuckoo- and cowbird-host species have been described, less is known about those of their respective parasites. Such sensory characterization is important for understanding the mechanisms underlying potential perceptual coevolutionary processes between hosts and parasites, as well as for better understanding each species' respective visual sensory ecology. We sequenced the short wavelength-sensitive type 1 (SWS1) opsin gene to predict the degree of UV- sensitivity in both of New Zealand's obligate parasitic cuckoo species, the Shining Cuckoo (Chalcites (Chrysococcyx) lucidus) and the Long-tailed Cuckoo (Urodynamis (Eudynamis) taitensis). We show that both species are predicted to possess SWS1 opsins with maximal sensitivity in the human-visible violet portion of the short-wavelength light spectrum, and not in the UV. Future studies should focus on the (mis)matching in host-parasite visual sensitivities with respect to host-parasite egg similarity as perceived by the avian visual system and the behavioral outcomes of foreign egg rejection.

Nonresident birds in tropical wet sclerophyll forest, northeast Queensland, Australia

Ten bird species were quantified as nonresidents in tropical wet sclerophyll forest, northeast Queensland, Australia: the banded honeyeater Certhionyx pectoralis (Gould, 1841), leaden flycatcher Myiagra rubecula (Latham, 1801), white-throated needletail Hirundapus caudacutus (Latham, 1802), black-faced monarch Monarcha melanopsis (Vieillot, 1818), shining bronze-cuckoo Chrysococcyx lucidus (Gmelin, 1788), satin flycatcher Myiagra cyanoleuca (Vieillot, 1818), spangled drongo Dicrurus bracteatus (Gould, 1842), slender-billed cicadabird Coracina tenuirostris (Jardine, 1831), satin bowerbird Ptilonorhynchus violaceus (Vieillot, 1816), and mistletoebird Dicaeum hirundinaceum (Shaw & Nodder, 1792). These nonresident species comprised 23% of the abundant and common bird species (n = 44) in the tropical wet sclerophyll forest during our study period (September 1995–October 1997). The greatest density of nonresident birds (0.674 individuals/ha) was during January–February (mid–late summer, wet season) when nine of...

Learned recognition of brood parasitic cuckoos in the superb fairy-wren Malurus cyaneus

Cuckoo hosts defend themselves against parasitism by means of mobbing, egg rejection, and chick rejection. However, each of these defenses is prone to costly recognition errors, and hosts are therefore more likely to deploy these defenses if they observe a cuckoo in the vicinity of their nest. The success of such response plasticity depends on accurate recognition of sympatric cuckoo species, but the mechanism by which hosts recognize cuckoos is largely unknown. Here, we use microgeographic variation in exposure to cuckoos in superb fairy-wren (Malurus cyaneus) hosts to test whether recognition of cuckoos is dependent on learning. We compare mobbing by superb fairy-wrens in response to freeze-dried specimens of a shining bronze-cuckoo (Chalcites lucidus) and a honeyeater control (Lichenostomus penicillatus) at 2 heavily parasitized sites and 2 rarely parasitized sites. Hosts at heavily parasitized sites mobbed the cuckoo intensively, including production of a distinctive whining call that appears to instigate group mobbing. By contrast, hosts at the rarely parasitized sites showed little reaction to the cuckoo, and their responses were similar to those given to the control. Furthermore, individuals with past experience of cuckoos mobbed the cuckoo specimen even when cuckoos were absent from the site, and did so significantly more than naive individuals. The extreme variation in response to cuckoos on such a small geographic scale and in relation to past exposure to cuckoos is consistent with learned recognition of cuckoos rather than local genetic adaptation.

Reliable Information Content and Ontogenetic Shift in Begging Calls of Grey Warbler Nestlings

AbstractThe most critical assumption of communication models regarding parent–offspring conflict is that food solicitation displays of genetic offspring are honest signals to elicit beneficial parental care. A critical requirement of honesty is the reliable change of perceivable aspects of begging calls with physiological needs. We experimentally tested whether and how the acoustic structure and begging call rate of individual Grey Warbler Gerygone igata nestlings change with hunger level and age. We also examined a rarely documented component of chick begging calls, namely the temporal dynamics of acoustic modulation after nestlings heard parental feeding calls. Begging call structure narrowed in frequency range and, surprisingly, decreased in amplitude as chick hunger levels increased. We also found that begging calls changed with chick age, with the frequency increasing and the duration decreasing for older chicks. These results indicate that the acoustic properties of nestling Grey Warbler begging calls are complex and may be used to signal several aspects of nestling traits, including hunger level and age (or size, a correlate of age). Overall, begging calls of Grey Warbler chicks appear to be honest, implying that parents are likely to benefit from relying on the acoustic features of their progeny’s calls which predict chick need. Our results have important implications regarding the reliability and information content of nestling solicitation signals for the brood parasite shining cuckoo Chrysococcyx lucidus exploiting Grey Warbler parental care, in that these begging‐call mimetic specialist cuckoos might also need to match closely the dynamics of acoustic features of their host chicks’ calls.

Begging call matching between a specialist brood parasite and its host: a comparative approach to detect coevolution

Studies of avian brood parasite systems have typically investigated the mimicry of host eggs by specialist parasites. Yet, several examples of similarity between host and parasite chick appearance or begging calls suggest that the escalation of host–parasite arms races may also lead to visual or vocal mimicry at the nestling stage. Despite this, there have been no large-scale comparative studies of begging calls to test whether the similarity of host and parasite is greater than predicted by chance or phylogenetic distance within a geographically distinct species assemblage. Using a survey of the begging calls of all native forest passerines in New Zealand, we show that the begging call of the host-specialist shining cuckoo (Chrysococcyx lucidus) is most similar to that of its grey warbler (Gerygone igata) host compared to any of the other species, and that this is unlikely to have occurred by chance. Randomization tests revealed that the incorporation of the shining cuckoo's begging calls into our species-set consistently reduced the phylogenetic signal within cluster trees based on begging call similarity. By contrast, the removal of the grey warbler calls did not reduce the phylogenetic signal in the begging call similarity trees. These two results support a scenario in which coevolution of begging calls has not taken place: the begging call of the host retains its phylogenetic signal, whereas that of the parasite has changed to match that of its host. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 208–216.

Seventeen years of predation by one suburban cat in New Zealand

The 558 prey items brought home by one domestic cat, recorded over its 17‐year lifetime, included 221 mice, 63 rats, 35 rabbits, 4 hares and 2 weasels. The cat hunted up to 600 m from the house, and prey was caught both inside and outside the 0.5 ha garden. Of the 223 birds brought in, 54 were native, including 43 silvereyes (Zosterops lateralis), but those killed were quickly replaced, so there was always a resident population of 1–2 pairs. The other known native birds comprised five fantails (Rhipidura fuliginosa), four warblers (Gerygone igata), a kingfisher (Halcyon sancta), and a shining cuckoo (Chrysococcyx lucidus). Only nine skinks (Cyclodina aenea) and one frog (Litoria raniformis) were brought in. The abundance of birds and reptiles in the garden showed no apparent change over the 17 years compared with the previous 15‐year‐period without a cat. By contrast, the cat exterminated the rabbit population in the garden, and “farmed” surrounding burrows during its whole life; all other prey killed declined in frequency after the cat was 8–9 years old.

Escalation of a coevolutionary arms race through host rejection of brood parasitic young.

Cuckoo nestlings that evict all other young from the nest soon after hatching impose a high reproductive cost on their hosts. In defence, hosts have coevolved strategies to prevent brood parasitism. Puzzlingly, they do not extend beyond the egg stage. Thus, hosts adept at recognizing foreign eggs remain vulnerable to exploitation by cuckoo nestlings. Here we show that the breach of host egg defences by cuckoos creates a new stage in the coevolutionary cycle. We found that defences used during the egg-laying period by host superb fairy-wrens (Malurus cyaneus) are easily evaded by the Horsfield's bronze-cuckoo (Chrysococcyx basalis), a specialist fairy-wren brood parasite. However, although hosts never deserted their own broods, they later abandoned 40% of nests containing a lone Horsfield's bronze-cuckoo nestling, and 100% of nests with a lone shining bronze-cuckoo nestling (Chrysococcyx lucidus), an occasional fairy-wren brood parasite. Our experiments demonstrate that host discrimination against evictor-cuckoo nestlings is possible, and suggest that it has selected for the evolution of nestling mimicry in bronze-cuckoos.

FREQUENCY OF EGG REJECTION BY POTENTIAL HOSTS OF THE NEW ZEALAND CUCKOOS

Abstract Host-specific brood parasites use a limited diversity of host species to raise their young. The two species of parasitic cuckoo that occur in New Zealand, Shining Cuckoo (Chrysococcyx lucidus) and Long-tailed Cuckoo (Eudynamys taitensis), are both host specific despite the availability of other apparently suitable species to act as hosts. To determine if host specificity has been shaped by the widespread occurrence of egg rejection among potential hosts, I tested the response of nine native passerine species to brood parasitism by the experimental addition of artificial cuckoo eggs to their nests. Artificial Shining Cuckoo eggs were rejected at least some of the time in eight of nine species tested, but levels of rejection were generally low. The majority of hosts accepted artificial Long-tailed Cuckoo eggs, and only the Brown Creeper (Mohoua novaeseelandiae) rejected eggs of both cuckoos. The occurrence of egg rejection in species currently not used as hosts (e.g., New Zealand Robin [Petroica au...