Azure-winged Magpie Research Articles

How should breeders react when aided by helpers?

In cooperatively breeding systems, breeders may reduce their provisioning to the brood when aided by helpers. However, this is found in only some species, and the reasons for the different reactions of breeders are far from clear. Recently, a paradoxical case of breeders in the azure-winged magpie, Cyanopica cyanus, increasing their contribution when aided by helpers has further complicated the issue. Existing models on the response of breeders consider only whether helpers contribute to increase the amount of food delivered to the brood. Helpers, however, can also contribute with other types of help that may increase the value of the whole brood for parents, such as reducing predation rate. Here we present a deterministic decision-making model to predict how parents should reduce or increase their parental effort on the basis of the relative role of both types of helpers' contributions: delivering food and/or dispensing protection against predation. The model can be used by field workers to make qualitative and quantitative predictions with their data. As an example, we show how data for the azure-winged magpie predicts the observed increase of parental contribution in the presence of helpers.

IBERIAN AZURE-WINGED MAGPIE CYANOPICA (CYANA) COOKI NESTLINGS BEGGING CALLS: CALL CHARACTERIZATION AND HUNGER SIGNALLING

ABSTRACT Nestling begging behaviour has long been seen as a signal by which nestlings solicit care from parents and most of the existing evidence provides some support for it being an honest signal. Begging is a multicomponent signal in which both sound and vision components are usually important. Although it is known that begging encodes information about nestling hunger the present knowledge about the specific behavioural features that convey the information is still scarce. The aim of this study was to describe begging calls of Iberian Azure-winged Magpie Cyanopica (cyana) cooki nestlings and examine how information on nestling hunger might be encoded in the begging calls. Nestlings were experimentally submitted to different periods of food deprivation and the call variation within individuals was studied. The young were individually tested and stimulated to beg by simulating parental visits. When subject to increasing food deprivation periods, nestlings increased the response level to simulated parental visits. The study also found that for the studied size differences, nestlings did not differ in their response level. Results confirmed that information on nestlings' hunger might be encoded in parameters of the calling behaviour. When the food deprivation periods increased, nestlings tended to start begging earlier, begged more often, extended their calling bout and increased the call duration, changing both at the level of the call and vocal begging bout. Overall the results support the view of begging as an honest signal, namely that begging should reflect nestling hunger and that only some call features might encode information about hunger.

Winter male plumage coloration correlates with breeding status in a cooperative breeding species

The function of colored ornaments is usually related to the signaling of individual quality in intra- and intersexual interactions. In cooperative breeding species, where only a fraction of the male population access the breeding status and the other fraction has the option to help breeding pairs, colored traits might provide the females with a reliable information on the quality of potential mate. Males of the cooperative breeding azure-winged magpies (Cyanopica cyanus) display conspicuous blue plumage coloration. Here we explored the role played by structural blue coloration of males and the probability of becoming a breeder or a helper. Birds were trapped during 4 consecutive years, and feather coloration was measured with a spectrometer. Males that became breeders had a more brilliant and saturated blue coloration and showed a more violet hue in the nonbreeding period compared with birds that became helpers. Breeding males also showed a seasonal decline in blueness, whereas the color properties of helpers were constant throughout the year. Blueness of individuals trapped in the nonbreeding period was positively correlated with body size and condition. These findings are consistent with a scenario in which nonbreeding blue plumage coloration may function as a signal of individual quality in the azure-winged magpie at the pair formation time and add to growing evidence suggesting that the nonbreeding season appears particularly important in impacting breeding roles in cooperative breeding birds.

Phylogeographic patterns in widespread corvid birds

Intraspecific genetic diversity and phylogeography of Corvus corone was investigated using the mitochondrial (mt) control region as a molecular marker. A split into two distinct mt lineages was observed. One represents individuals from a wide geographic range spanning from England to the Russian Far East (Kamchatka), while the other one was found in the Primorye and Khabarovsk regions (southern parts of Russian Far East) as well as Japan. For comparison, we investigated several widespread Palearctic corvid taxa with respect to their phylogeographic patterns. A deep split into two lineages was revealed in five cases: Besides C. corone, within Corvus frugilegus, Pica pica, and between the species pairs Corvus monedula– Corvus dauuricus and Cyanopica cyanus– Cyanopica cooki. Although these taxa display a variety of distribution patterns, from disjunct, para/allopatric to continuous, the genetic pattern and level of divergence between clades is very similar. This implies that the differentiation started in about the same time range. In contrast, no differentiation into highly divergent lineages was detected in Corvus corax, Perisoreus infaustus, and Nucifraga caryocatactes. We try to explain the two phylogeographic patterns in corvid birds with ecological factors accompanying the changing climatic conditions during the Pleistocene. The deep genetic splits within several widely distributed Palearctic corvids are discussed with respect to taxonomic questions.

Effect of Japanese lesser sparrowhawks Accipiter gularis on the nest site selection of azure‐winged magpies Cyanopica cyana through their nest defending behavior

The frequency of azure‐winged magpies Cyanopica cyana that nest in association with breeding Japanese lesser sparrowhawks Accipiter gularis was compared between the 1990s and 2000s. During 1990–1994 azure‐winged magpies nested within 50 m of their nests in all of the hawk nest sites studied. During 2005–2006, however, the magpies nested in only two of nine hawk nest sites. During the 1990s Japanese lesser sparrowhawks chased jungle crows away when they intruded within 50 m of their nest. During the 2000s, on the other hand, the hawks attempted to expel few crows at a distance of more than 10 m from their nest. As a result of it, the predation rate of simulated magpie nests located in the hawk nest sites was significantly higher during the 2000s. This suggests that the magpies have the ability to assess the defending behavior of the hawks and judge whether they can rely on their defense. Most azure‐winged magpies may stop nesting in association with breeding Japanese lesser sparrowhawks because of the reduced defending range of their nest sites.

Effect of Japanese lesser sparrowhawks Accipiter gularis on the nest site selection of azure-winged magpies Cyanopica cyana through their nest defending behavior

Effect of Japanese lesser sparrowhawks Accipiter gularis on the nest site selection of azure-winged magpies Cyanopica cyana through their nest defending behavior

Polychlorinated dibenzo- p-dioxins and dibenzofurans in eggs of eight avian species from Dongting Lake, China

Concentrations of polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in eggs of eight avian species collected from Dongting Lake of China to assess residue levels, accumulation patterns, and toxic potential in different avian species. Concentrations of total 2,3,7,8-substituted PCDD/Fs were in the range of 10.8–182 pg g −1 lipid weight. Eggs of great egret and lesser pied kingfisher contained higher levels of PCDD/Fs than eggs of other species, indicating the specific exposure and accumulation of PCDD/Fs relating to feeding habits and the life span. PCDD/Fs congener patterns varied among species. The patterns of PCDD/Fs in the eggs may be influenced by feeding habits, specific elimination, and metabolism. In general, concentrations of PCDDs were higher than those of PCDFs in avian eggs. On basis of lipid weight, total 2,3,7,8-TCDD toxic equivalents (TEQs) calculated based on the WHO TEFs for birds ranged from 2.04 to 42.0 pg g −1; and on basis of wet weight, total WHO-TEQs ranged from 0.19 to 1.59 pg g −1. 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD were the major contributors to TEQ concentration in most avian eggs, whereas 1,2,3,4,7,8-HxCDD also accounted for a major portion of TEQs in eggs of azure-winged magpie. Values of TEQs in avian eggs were lower than toxic threshold values, implying risk reduction and natural restoration of PCDD/Fs contamination in Dongting Lake region.

Sex determination of Iberian Azure‐winged Magpies Cyanopica cyanus cooki by discriminant analysis of external measurements

Like all corvids, the Azure‐winged Magpie Cyanopica cyanus is sexually monomorphic in plumage, making it difficult to distinguish between males and females in the field. We examined sexual size dimorphism in a population of Iberian Azure‐winged Magpies C.c. cooki and used a discriminant function analysis based on five morphological characters to determine the sex of first‐year and adult individuals. Females were significantly smaller than males for all tested variables within each age class except for keel length of first‐year individuals. In both sexes, wing length of adults was greater than that of yearlings, but only males showed significant differences in tail length between age classes (longer in first‐year birds). Stepwise discriminant analysis indicated that tail length and head plus bill length were the most accurate variables in a discriminant function model, predicting the sex of yearlings with about 90% accuracy. Adding wing length to the model yielded the same level of accuracy for adults. We propose a simple system to sex Iberian Azure‐winged Magpies, using only two or three variables easily measured in the field, which provides classification with a high level of accuracy.

Nest defense by Iberian azure-winged magpies (Cyanopica cyanus): do they recognize the threat of brood parasitism?

The ultimate goal of nesting is the production of young and therefore predation and brood parasitism may constrain reproductive success. Breeding azurewinged magpies (Cyanopica cyanus) were exposed to mounts of an sparrowhawk (Accipiter nisus) (i.e. an avian predator on adult and fledged chicks), a female great spotted cuckoo (Clamator glandarius) (i.e. a brood parasite that also preys on eggs and chicks), and a mistle thrush (Turdus viscivorus) (i.e. an innocuous control) at different stages throughout the breeding cycle. In addition, the nest defensive behaviour of the azure-winged magpie and the common magpie (Pica pica) (the current favorite host for the great spotted cuckoo in Iberia) were compared. Azure-winged magpies behaved more aggressively (i.e. higher intensity and shorter latency to an aggressive response) towards the brood parasite and the predator mounts than towards the control. The number of individuals defending a nest was higher when exposed to a predator than to a control or a brood parasite. Aggressiveness against the brood parasite mount was not higher at laying as compared to other breeding periods. Azure-winged magpies defended more intensely than magpies when facing a great-spotted cuckoo, although the number of birds attacking the decoy was similar for both species. Thus, azure-winged magpies appear to perceive a different level of threat and defend their nests accordingly. We discuss the relevance of these results in explaining the current absence of brood parasitism in Iberian azure-winged magpies.

Positive correlation between helpers at nest and nestling immune response in a cooperative breeding bird

In cooperatively breeding species, helpers may contribute to the success of the brood by increasing the number of independent offspring, but also, they may affect offspring condition and, hence, their survival and recruitment into the breeding population. This second type of benefits is rarely included in theoretical models or assessed in field studies. Immune response is a good proxy of individual quality and fitness, and there is good evidence that the performance of the immune system of chicks during the nestling phase is related to their chances of survival and future reproduction. However, no study has so far explored whether helpers at the nest might contribute to enhance immune functioning of nestlings in species with a cooperative breeding system. Here we investigate this issue in the azure-winged magpie (Cyanopica cyanus) and found for the first time a positive correlation between the number of helpers at nest and the cell-mediated immune response of nestlings. This effect was not explained by a general improvement of body condition of chicks because it was independent of individual variation in body mass or tarsus length. Our results suggest that helping can have subtle effects on the quality of offspring that may influence their survival and future reproduction.

Parents increase their parental effort when aided by helpers in a cooperatively breeding bird

In cooperatively breeding species, parents may be assisted by other individuals to feed the young. How breeding parents react when they receive help is poorly understood. Evidence suggests that parents usually maintain their feeding effort when starvation of chicks is common, and reduce it when other risks such as predation are more important for chick survival, although some recent examples do not fit this pattern. In no case, however, have parents been found to increase their effort when they have helpers. We investigated this issue in a rarely studied cooperative breeder, the azure-winged magpie, Cyanopica cyanus . Breeders increased their provisioning rate when aided by helpers. However, chick starvation was rare and it was equally so in nests with and without helpers. The incidence of predation, conversely, was significantly lower in the presence of helpers. Helpers provisioned at a lower rate than parents but buffered the effect of adverse conditions in bad years in the nests they assisted. To our knowledge, these findings show for the first time that parents can increase their investment in the current brood in the presence of helpers, a result that does not seem to have been covered by current theory of cooperative breeding.

Feathers at nests are potential female signals in the spotless starling

Although the presence of feathers in the nest is widespread among birds, it has not been previously suggested that feathers can be used as sexual signals. Females of the spotless starling (Sturnus unicolor) regularly carry feathers to their nest, mostly during laying and incubation. We show that the arrangement of these feathers was non-random with respect to the side (obverse or reverse) placed upwards (which can be viewed from the nest entrance). Feathers of the wood pigeon (Columba palumbus) and the spotless starling, which exhibit higher ultraviolet and visible reflectance on their reverse side, were predominantly placed with this side upwards. On the contrary, feathers of the jay (Garrulus glandarius) were predominantly found exhibiting the obverse side, which possesses higher reflectance in this species. Feathers of the azure-winged magpie (Cyanopica cyana), with similar reflectance values on either side, were placed indiscriminately in obverse and reverse positions. The results suggest that feathers are arranged to maximize their conspicuousness within the nest and hence that they might be potentially used as intraspecific signals.

No brood parasitism by the Great Spotted Cuckoo Clamator glandarius on the Azure-winged Magpie Cyanopica cyanus

Capsule No case of parasitic interaction was found after 12 years of intensive monitoring of a marked population in Spain where both species are sympatric. Aims To evaluate whether the Azure-winged Magpie is parasitized, and suggest possible causes that affect its relationship with the Great Spotted Cuckoo. Methods Data from a long-term field study of marked individuals in a population of Azure-winged Magpie in Spain, were collected from about 60 nests per year over 12 years. Results Although common in the area, no eggs or young of the Great Spotted Cuckoo were found in an Azure-winged Magpie nest. Conclusion The Great Spotted Cuckoo does not appear to parasitize the Azure-winged Magpie, and we suggest that elevated predation rates on nests may be an important, overlooked factor potentially affecting the choice of host species by this brood parasite.

Characteristics of brood parasitism by Common Cuckoos on Azure-winged Magpies, as illustrated by video recordings

ABSTRACT To clarify the influence of host aggression on the Common Cuckoo Cuculus canorus, the cuckoo's parasitic behaviour was compared between a new host, Azure-winged Magpie Cyanopica cyana, and an old host, Great Reed Warbler Acrocephalus arundinaceus. Magpies exhibited less aggression towards cuckoos than did the warblers, and hardly attacked cuckoos at the nest. Cuckoos spent longer in the vicinity of nests while parasitizing magpie nests than when parasitizing reed warbler nests; possibly because of the magpie's lower aggression. Cuckoos parasitized magpie nests later in the day than reed warblers, despite the lower aggression of the magpies. The effect of host aggression on cuckoo parasitic behaviour and the adaptive significance of parasitic behaviour are discussed.

Behavior of radio-tracked Common Cuckoo females during the breeding season in Japan

ABSTRACT The breeding behavior of Common Cuckoo Cuculus canorus females was studied in detail by individual marking, radio-tracking, and automatic recording of radio signals. A total of 132 female cuckoos was captured, and radio transmitters were attached to 44 of them. The female cuckoos parasitised three different types of hosts: Azure-winged Magpies Cynopica cyane, Great Reed Warbler Acrocephalus arundinaceus and Bull-headed Shrike Lanius bucephalus. Female cuckoos using magpie hosts were radio-tracked for a total of 131.1 hours, and females using warbler hosts were radio-tracked for a total of 142.1 hours. The total time for cuckoos using shrike hosts was 12.6 hours. Female cuckoos were found to have distinct breeding and feeding areas, which they commuted between every day. Dominant females maintained strict breeding site tenacity throughout the breeding season. Each female specialized on one host type, knew almost all of the host nests in their breeding areas, and laid eggs selectively among the nes...

Synchronic east-west divergence in azure-winged magpies (Cyanopica cyanus) and magpies (Pica pica)*

Morphometric and genetic analyses were performed to investigate the relationships between populations of the azure-winged magpie (Cyanopica cyanus). In the morphometric analysis 193 specimens were included representing seven of the nine currently accepted subspecies. Among eight characters analysed, four showed significant differences between samples from Spain and Asia. In contrast, the Asian populations/subspecies are not differentiated morphologically except Cyanopica cyanus japonica. The genetic analysis was based on two mitochondrial sequences (control region, cytochrome b gene). The results are in accordance with the morphometric analysis, showing a clear distinction between birds from the western and eastern distribution ranges. The differentiation of C. c. japonica is not found at the sequence level. Both genetic and morphological data support species status of C. cyanus and Cyanopica cooki. The magpie (Pica pica) was included in the phylogenetic study for comparing intraspecific variation. As in C. cyanus, two clearly separated groups are found, one of them containing the far-eastern populations (Pica pica jankowskii and Pica pica sericea) and the other the remaining subspecies studied. For both the azure-winged magpie and the magpie the sequence data imply an east–west differentiation, probably caused by long lasting isolation that may have even started in the Pliocene or repeated expansions/restrictions of distribution ranges during the Pleistocene.

Environmental Constraints and Cooperative Breeding in the Azure-Winged Magpie

AbstractWe studied the Azure-winged Magpie's (Cyanopica cyanus) breeding performance and cooperative breeding system in two consecutive breeding seasons with varying climate conditions. We found a strong year effect on most breeding parameters. Helpers were more frequent in the year with more severe weather conditions, and helper presence significantly increased provisioning rates and breeding success of the breeders. Some of the helpers were adults that had failed on a previous breeding attempt, while others were offspring of the breeding pair from the previous season. We suggest that helping in this species is a “best-of-a-bad-job” strategy, in which individuals facing a breeding attempt with low prospects of success, or with high costs associated, assist others.Imposiciones Ambientales y Cría Cooperativa en Cyanopica cyanusResumen. Estudiamos el éxito reproductivo y el sistema de cría cooperativa en Cyanopica cyanus en dos períodos reproductivos consecutivos con condiciones climáticas muy diferentes. Encontramos un fuerte efecto del año en la mayoría de los parámetros reproductivos. Los ayudantes fueron más frecuentes durante el año con peores condiciones climatológicas, y su presencia aumentó significativamente las tasas de ceba y el éxito reproductivo de las parejas. Algunos de los ayudantes eran adultos que habían fracasado en un intento de reproducción anterior, mientras que otros eran hijos de la pareja reproductora nacidos el año anterior. Sugerimos que el comportamiento de ayudar en esta especie representa una estrategia de “dentro de lo malo, lo mejor”, en la cual algunos individuos en lugar de realizar un intento de reproducción con pocas probabilidades de éxito o muy costoso, se dedican a ayudar a otros.

Egg rejection by Iberian azure‐winged magpiesCyanopica cyanusin the absence of brood parasitism

The Iberian azure‐winged magpieCyanopica cyanusshows a remarkable ability to discriminate against great spotted cuckooClamator glandariuseggs. Here, I studied whether egg recognition in this species could be a derived feature resulting from intra‐specific brood parasitism. Azure‐winged magpies showed a very high level of discrimination and rejection of great spotted cuckoo models (73.7%), and of conspecific eggs (42.8%), even when no evidence of great spotted cuckoo or conspecific brood parasitism has been found in the population. Azure‐winged magpie discriminated more readily than magpies, the current favourite host of the great spotted cuckoo. The high rejection rate of conspecific eggs by the azure‐winged magpie suggests that it is quite possible that egg discrimination in this species evolved in response to conspecific brood parasitism rather than to cuckoo parasitism.

ENVIRONMENTAL CONSTRAINTS AND COOPERATIVE BREEDING IN THE AZURE-WINGED MAGPIE

Abstract We studied the Azure-winged Magpie's (Cyanopica cyanus) breeding performance and cooperative breeding system in two consecutive breeding seasons with varying climate conditions. We found a strong year effect on most breeding parameters. Helpers were more frequent in the year with more severe weather conditions, and helper presence significantly increased provisioning rates and breeding success of the breeders. Some of the helpers were adults that had failed on a previous breeding attempt, while others were offspring of the breeding pair from the previous season. We suggest that helping in this species is a “best-of-a-bad-job” strategy, in which individuals facing a breeding attempt with low prospects of success, or with high costs associated, assist others. Imposiciones Ambientales y Cria Cooperativa en Cyanopica cyanus Resumen. Estudiamos el exito reproductivo y el sistema de cria cooperativa en Cyanopica cyanus en dos periodos reproductivos consecutivos con condiciones climaticas muy diferentes...

Testosterone and helping behavior in the azure-winged magpie ( Cyanopica cyanus ): natural covariation and an experimental test

In this study, we investigated patterns of natural covariation between testosterone and reproductive status in a cooperatively breeding bird species, the azure-winged magpie (Cyanopica cyanus). To assess the relationship between testosterone and breeding behavior, we also manipulated testosterone (T) levels early in the season (before breeding started) using testosterone-filled or empty implants. Our results do not support the hypothesis that circulating testosterone levels affect the occurrence of helping behavior in the azure-winged magpie. Helping males had similar T levels to breeding males. Furthermore, experimentally augmented plasma T did not affect the likelihood of becoming either a helper or a breeder. Overall, these results are consistent with previous findings in other bird species and only give some support to the behavioral suppression hypothesis, suggesting that helping in the azure-winged magpie is a flexible behavioral option moderated in the short-term by social and ecological factors. Experimentally elevated testosterone levels, however, reduced the reproductive success of male breeders because of markedly lower levels of paternal care, had similar effects on their mates, but had the contrary effect on helpers, which raised levels of parental effort. We suggest increases in the share of paternity and in social prestige as possible explanations for these results.