Starlings Sturnus Research Articles

Brood size of twelve farmland bird species in Sweden during 1962—2001

Several farmland bird species are declining in Sweden. We investigated if the population decreases are linked to smaller broods or a higher rate of unhatched eggs. The number of broods ringed and the average number of nestlings in these broods from 1962 to 2001 were analysed for twelve species: Skylark Alauda arvensis, Swallow Hirundo rustica, House Martin Delichon urbica, Meadow Pipit Anthus pratensis, White Wagtail Motacilla alba, Wheatear Oenanthe oenanthe, Whitethroat Sylvia communis, Starling Sturnus vulgaris, House Sparrow Passer domesticus, Tree Sparrow Passer montanus, Linnet Carduelis cannabina and Yellowhammer Emberiza citrinella. Only two of the investigated species, the Tree Sparrow and the Yellowhammer, showed a statistically significant decline in average brood size over time. We conclude that changes in brood size alone cannot explain the decline in several farmland bird species. The House Sparrow showed an increase in the number of dead nestlings and data for House Sparrow, Tree Sparrow and Whitethroat indicated that a higher rate of unhatched eggs might be a problem.

Habitat influences on urban avian assemblages

Urbanization is increasing across the globe and there is growing interest in urban ecology and a recognition that developed areas may be important for conservation. We review the factors influencing urban avian assemblages, focusing on habitat type and anthropogenic resource provision, and analyse data from a common bird monitoring scheme to assess some of these issues. The review suggests that (1) local factors are more important than regional ones in determining the species richness of urban avian assemblages, raising the potential for the management of urban sites to deliver conservation; (2) habitat fragmentation frequently influences urban avian assemblages, with the effects of patch size being greater than those of isolation, and (3) urban bird assemblages appear to respond positively to increasing the structural complexity, species richness of woody vegetation and supplementary feeding, and negatively to human disturbance. Data from Britain's Breeding Bird Survey, combined with habitat data obtained from aerial photographs, were used to assess a number of these issues at the resolution of 1‐km squares. Green‐space constituted 45% of these squares, and domestic gardens contributed 50% of this green‐space, though their contribution to large continuous patches of green‐space was negligible. There was no significant positive correlation between the densities of individual species in urban areas and surrounding rural areas. Rural species richness declined with increasing latitude, but urban species richness was not correlated with latitude. This contrast contributes to slightly higher avian species richness in rural squares in Southern England than urban ones. Occupancy and abundance were strongly positively correlated in urban avian assemblages, and some indicator species of conservation concern occurred in few urban areas and at low densities. Such species will require conservation action to be precisely targeted within urban areas. Of the urban indicators of conservation concern, only the House Sparrow Passer domesticus and Common Starling Sturnus vulgaris were more abundant in urban than rural areas. Moreover, the densities of these two species were strongly and positively correlated, indicating that they may be limited by shared resources, such as nest‐sites or supplementary food. There was little evidence that high densities of nest‐predating corvids were associated with reduced densities of their prey species. Species richness and the densities of individual species frequently declined with an increasing number of buildings. Current trends for the densification of many British urban areas are thus likely to be detrimental for many bird species.

Taxonomic recommendations for British birds: Fifth report

Taxonomic recommendations for British birds: Fifth report

The starvation–predation risk trade‐off, body mass and population status in the Common Starling Sturnus vulgaris

It is theoretically and empirically well established that body mass variation in small birds reflects a trade‐off between starvation risk and predation risk. This occurs because carrying increased fat reserves reduces starvation risk but also results in a higher predation risk due to reduced escape flight performance and/or the increased foraging exposure needed to maintain a higher body mass. In principle, therefore, the theory of mass‐dependent predation risk could be used to understand how a bird perceives and responds to the risks in its environment, because its mass will reflect the predictability of foraging opportunities and predation risk. Mass in birds may then provide a relatively straightforward way of assessing the foraging environment of birds and so the potential conservation problems a species faces. This study tests, for the first time for any species, how body mass changes in response to changing starvation risk, changing predation risk and changing population status. Common Starling Sturnus vulgaris mass varies as predicted by starvation–predation risk trade‐off theory: mass is lower when foraging conditions are more favourable and when predation risk is increased. The populations that are declining the most strongly have higher mass, which is most likely indicative of a poor foraging environment, leading to lower relative survival. The results suggest that increased mass in Starlings, and possibly in other species, may provide an indication of the poor quality of the foraging environment and/or rapidly declining populations.

Responses of birds to the characteristics of farm windbreaks in central New South Wales, Australia

In parts of Australia where the clearing of native vegetation has been widespread the establishment of windbreaks is a common farming practice. There is some evidence that birds respond to certain characteristics of windbreaks, particularly width. This is the first study to investigate such effects in Australia. Six properties, containing 61 windbreak sites, were surveyed for birds 12 times between 1993 and 1997. Generalised linear models were used to test relationships between 19 predictor variables and bird community attributes, including the densities of 14 species of birds. Canonical variate analysis was undertaken to discriminate among four types of windbreaks and their avifauna. Species known to be declining in the region and uncommon (<100 observations) woodland birds were more abundant in wider and more floristically diverse windbreak sites. Several native species had a positive response to tree-height, density of under-storey, structural diversity, the proportion of native plant species in the site or the proximity of remnant bushland. The density of introduced bird species, as a group, was strongly negatively related to the proportion of native plants and, for one species, Common Starling (Sturnus vulgaris), to width of windbreak. Recommendations for windbreak design are provided and include: using a diversity of native plants; providing adequate width, preferably over 20 m; and having a diversity of understorey densities. It is also recommended that patterns of experimental windbreaks are created that could be used for formal hypothesis testing.

Song Learning After Isolation in the Open-Ended Learner the European Starling: Dissociation of Imitation and Syntactic Development

Abstract We performed two studies to test whether the ability of open-ended learners to acquire new songs as adults depends on their having learned normal songs as juveniles. European Starlings (Sturnus vulgaris) were kept in isolation for their first year. In the first study the birds were housed in a group with a wild-caught adult male following isolation. The subjects imitated each other but not the wild male and failed to develop normal phonology or syntax. In the second study each yearling was housed individually with a wild-caught adult male following isolation. These subjects developed good phonology and syntax but copied few or no song motifs from the wild adults. Taken together, the two studies indicate that starlings are capable of imitating new motifs and of acquiring species-typical phonology and syntax after a year of isolation. The contrasting results of the two studies suggest that imitation and the development of syntax are independent processes subject to different influences.

Effect of Old Nest Material on Nest Site Selection and Breeding Parameters in Secondary Hole Nesters — a Review

Hole nesting birds, due to the long lasting nature of cavities, use their nest sites for many years. Therefore, they may face the problem of the presence of nest material from previous breeding seasons. For a long time, the problem of old nest presence was not addressed in studies of this group of birds because nestboxes, a useful tool in studies of hole nesters, were cleaned by investigators, with old nests removed before each breeding season. In this review, the available results of experiments related to the effects of old nests on hole nesting birds are collected, recapitulated and discussed. The possible effects of old nests on nest site choice and breeding parameters, such as phenology, clutch size, fledging condition, as well as on ectoparasite numbers in a new nest, are presented. The findings show that studies on the problem of old nests started to be conducted mainly in the early 1990's, and to date more then thirty papers have been published related to this topic. The most frequent subjects of such studies in Europe were the Pied Flycather Ficedula hypoleuca, Blue and Great Tits Cyanistes caeruleus, Parus major, and European Starling Sturnus vulgaris, while in North America — the House Wren Troglodytes aedon and Eastern Bluebird Sialia sialis. The analysis of existing papers reveals that a majority of studies did not find any significant effect of old nest presence on nest site selection. In most papers, the presence of old nests did not influence birds' breeding parameters. Worse reproductive output in nestboxes containing old nests was found very rarely, and in particular seasons or study areas. Data on ectoparasite occurrence in relation to the presence of old nest material were presented only in a few papers. Fewer fleas were found in new nests built in artificially cleaned sites compared to sites containing old nests. The abundance of mites and blow fly larvae was not related to nestbox treatment. The results of this review suggest that there is no clear pattern of effects of old nest presence on hole nesters' breeding. It seems that the location of the study area, which influences the time available for birds' reproduction, is especially important for migratory species, and the impact of the ectoparasites dominating in a given study area may influence obtained results. This paper also suggests the direction of future work in this topic. Of most importance are studies carried out in natural tree holes, as the decomposition rate of old nest material could be much higher in such cavities than in nestboxes, and studies providing detailed descriptions of the costs and benefits of nest site cleaning behaviour of the birds themselves.

Changing demography and population decline in the Common Starling Sturnus vulgaris: a multisite approach to Integrated Population Monitoring

Understanding demography is critical for understanding the causes underlying population declines, and for initiating and monitoring policies to reverse them. A method of fitting demographic models directly to avian count data recorded at a sample of census sites is described. The model is applied to national and regional counts of Common Starling Sturnus vulgaris in Britain for the period 1965–2000. Starlings have declined markedly during this time and are now on the list of birds of highest conservation concern. Although there have been small changes in various aspects of breeding success over this time, the analysis shows that these are unlikely to have made much impact on the long‐term status of the species. By incorporating estimates of survival, based upon recoveries of ringed birds, the model suggests that the pronounced national decline in Starling numbers since a period of stability in the 1970s is most likely to be due to changes in the survival of first‐year birds. This narrows the candidate range of environmental factors which might influence the decline and implicates changes in resource availability.

Long-term trends in first arrival and first egg laying dates of some migrant and resident bird species in northern Italy

Climate change is affecting the phenology of seasonal events in Europe and the Northern Hemisphere, as shown by several studies of birds' timing of migration and reproduction. Here, we analyse the long-term (1982-2006) trends of first arrival dates of four long-distance migratory birds [swift (Apus apus), nightingale (Luscinia megarhynchos), barn swallow (Hirundo rustica), and house martin (Delichon urbicum)] and first egg laying dates of two migrant (swift, barn swallow) and two resident species [starling (Sturnus vulgaris), Italian sparrow (Passer italiae)] at a study site in northern Italy. We also addressed the effects of local weather (temperature and precipitation) and a climate index (the North Atlantic Oscillation, NAO) on the interannual variability of phenological events. We found that the swift and the barn swallow significantly advanced both arrival and laying dates, whereas all other species did not show any significant temporal trend in either arrival or laying date. The earlier arrival of swifts was explained by increasing local temperatures in April, whereas this was not the case for arrival dates of swallows and first egg laying dates of both species. In addition, arrival dates of house martins were earlier following high NAO winters, while nightingale arrival was earlier when local spring rainfall was greater. Finally, Italian sparrow onset of reproduction was anticipated by greater spring rainfall, but delayed by high spring NAO anomalies, and swift's onset of reproduction was anticipated by abundant rainfall prior to reproduction. There were no significant temporal trends in the interval between onset of laying and arrival in either the swift or the barn swallow. Our findings therefore indicate that birds may show idiosyncratic responses to climate variability at different spatial scales, though some species may be adjusting their calendar to rapidly changing climatic conditions.

Crop use by introduced bird species in winter in relation to crop structure and seed resources

Capsule Most species preferred to forage in grassland where seed resources were more abundant and the vegetation was uniform in height but heterogeneous in density. Aim To determine the influence of crop composition and structure, and seed food resources on the distribution of introduced bird species on New Zealand farmland in winter. Methods Birds were counted on 90 ha of mixed cropping farmland during mid- and late-winter periods, 2004. The presence or absence of six introduced species (Blackbird Turdus merula, Skylark Alauda arvensis, House Sparrow Passer domesticus, Goldfinch Carduelis carduelis, Yellowhammer Emberiza citrinella and Starling Sturnus vulgaris) in fields was investigated in relation to crop composition and structure and seed abundance. Results Species–habitat associations varied over time and between species. Blackbird, House Sparrow, Yellowhammer and Starling were associated more frequently with grassland than arable crops during at least one survey. Seed abundance was a significant predictor of the occurrence of all species except House Sparrow, while crop structure was a predictor of only Goldfinch, Yellowhammer and Starling occurrence. Conclusion During the winter, the distribution of six introduced bird species in the lowland cropping area was related to habitat composition, vegetation structure, and seed food resources. The preference for grassland habitats was probably determined by the vegetation structure and seed resources in these areas. The trend for increased use of supplementary animal feed in livestock farming in New Zealand may help sustain introduced bird populations. A larger-scale study is needed to investigate the generality of the species–habitat associations detected in this study at the landscape scale.

NESTLING IMMUNOCOMPETENCE IS AFFECTED BY CAPTIVITY BUT NOT INVESTIGATOR HANDLING

Abstract Environmental conditions during the neonatal period can affect the growth, physiology, behavior, and immune function of birds. In many avian studies the nestling environment includes investigator handling of young, which may be stressful. While neonatal handling is known to affect the adult phenotype in rats, the effects of handling on development have rarely been examined in wild birds. We examined the effect of short, repeated periods of neonatal handling on avian growth and immune system development. We subjected American Kestrels (Falco sparverius) and European Starlings (Sturnus vulgaris) to 15 min of daily investigator handling throughout the nestling period, while controls remained undisturbed. Immediately prior to fledging we assessed cutaneous immunity, humoral immunity, mass, and degree of fluctuating asymmetry. Daily handling did not significantly affect any of these measurements. We also addressed the possibility that treatment differences would appear only when birds were challenged ...

SELENIUM ACCUMULATION IN EUROPEAN STARLINGS NESTING IN A SELENIUM-CONTAMINATED ENVIRONMENT

Abstract I compared selenium (Se) levels in blood, liver, egg, and diet samples from European Starlings (Sturnus vulgaris) nesting at Kesterson Reservoir, Merced County, California and the surrounding area. Concentrations were highest in adult and nestling blood (8.3 and 5.5 µg g−1, respectively), nestling liver (7.5 µg g−1), and eggs (4.6 µg g−1) from nest boxes in interior parts of Kesterson compared to those from the perimeter (adult and nestling blood = 4.0 and 1.4 µg g−1, respectively, nestling liver = 4.7 µg g−1, eggs = 2.8 µg g−1) and off-site (nestling blood = 3.8 µg g−1, liver = 4.3 µg g−1, egg = 2.7 µg g−1). No hatching failure or embryo effects were observed. Although I found strong positive relationships in Se levels among tissues and eggs, variability of dietary exposure and differences in depuration rates across tissues confounds prediction of Se concentration. Nevertheless, I found blood Se to be a good indicator of dietary exposure that can be sampled nondestructively.

SONG LEARNING AFTER ISOLATION IN THE OPEN-ENDED LEARNER THE EUROPEAN STARLING: DISSOCIATION OF IMITATION AND SYNTACTIC DEVELOPMENT

Abstract We performed two studies to test whether the ability of open-ended learners to acquire new songs as adults depends on their having learned normal songs as juveniles. European Starlings (Sturnus vulgaris) were kept in isolation for their first year. In the first study the birds were housed in a group with a wild-caught adult male following isolation. The subjects imitated each other but not the wild male and failed to develop normal phonology or syntax. In the second study each yearling was housed individually with a wild-caught adult male following isolation. These subjects developed good phonology and syntax but copied few or no song motifs from the wild adults. Taken together, the two studies indicate that starlings are capable of imitating new motifs and of acquiring species-typical phonology and syntax after a year of isolation. The contrasting results of the two studies suggest that imitation and the development of syntax are independent processes subject to different influences.

Respiratory water loss during rest and flight in European Starlings (Sturnus vulgaris)

Respiratory water loss in Starlings (Sturnus vulgaris) at rest and during flight at ambient temperatures (T(amb)) between 6 and 25 degrees C was calculated from respiratory airflow and exhaled air temperature. At rest, breathing frequency f (1.4+/-0.3 Hz) and tidal volume Vt (1.9+/-0.4 ml) were independent of T(amb), but negatively correlated with each other. Mean ventilation at rest was 156+/-28 ml min(-1) at all T(amb). Exhaled air temperature (T(exh)) at rest increased with T(amb) (T(exh) = 0.92.T(amb)+12.45). Respiratory water loss at rest averaged 0.18+/-0.09 ml h(-1) irrespective of T(amb). In flying Starlings f was 4.0+/-0.4 Hz and independent of T(amb). Vt during flight averaged 3.6+/-0.4 ml and increased with T(amb) (Vt = 0.06.T(amb)+2.83) as, correspondingly, did ventilation. T(exh) during flight increased with T(amb) (T(exh) = 0.85.T(amb)+17.29). Respiratory water loss during flight (average REWL(f) = 0.74+/-0.22 ml h(-1)) was significantly higher than at rest and increased with T(amb). Our measurements suggest that respiratory evaporation accounts for most water loss in flying Starlings and increases more than cutaneous evaporation with rising ambient temperature.

First record of Rose-coloured Starling Sturnus roseus for Ethiopia and sub-Saharan Africa

First record of Rose-coloured Starling Sturnus roseus for Ethiopia and sub-Saharan Africa

Avian translocations and disease; implications for New Zealand conservation

There is little published information on the pathogens present in New Zealand passerines. We report here on a preliminary survey of selected pathogens and haematology profiles for seven species in the Auckland region. Avian translocations are commonly used for the recovery of threatened species. Translocations may increase the risk of spreading disease to immunologically na�ve populations. It is therefore important to take every opportuntty to gather baseline disease data and test hypotheses associated with disease. Blood, cloacal and faecal samples were collected from Fernbird Bowdleria punctata, Tui Prosthemadera novaeseelandiae, Bellbird Anthornis melanura, Tomtit Petroica macrocephala, New Zealand Robin Petroica australis, Whitehead Mohua albicilla and Starling Sturnus vulgaris during four translocations to and from Tiritiri Matangi Island. Birds (n = 137) were also examined for external lesions typical of avian pox. Blood samples (n = 40) were screened by microscopy for Plasmodium spp., Atoxoplasma spp. and other blood parasites and a differential white blood cell count was made. Cloacal swabs (n = 38) were cultured for Yersinia spp., Salmonella spp. and Campyobaeter spp. Faecal samples were screened for coccidia spp. (n = 28). An unidentified coccidian sp. and a Haemoproteus sp. were detected in one Fembird and one robin respectively. No other organisms with the potential to cause disease were detected. Despite the effort required to complete disease screening, we argue that disease samples and baseline haematology normal values should be collected at an opportunities. We make recommendations for future disease screening, and discuss the importance and potential significance of disease to the conservation of New Zealand's biodiversity.

Has the reduction in nest-site competition from Starlings Sturnus vulgaris been a factor in the recent increase of Great Spotted Woodpecker Dendrocopos major numbers in Britain?

Capsule A national decline in Starling numbers and the reduction in nest-site competition may have contributed to the increase in nest success, numbers and habitat distribution of the Great Spotted Woodpecker in Britain. Aims To examine the evidence that nest-site competition from Starlings was once a significant factor in the breeding performance and phenology of the Great Spotted Woodpecker. Methods The causes of nest failure, daily nest survival and first-egg dates of the Great Spotted Woodpecker from an intensive local study (1984–2003) and the national British Trust for Ornithology (BTO) Nest Record Cards are analysed in relation to nesting Starling density and BTO Common Bird Census/Breeding Bird Survey Starling population trends. Results Nest-site interference from Starlings was cited as a significant cause of breeding failure in the Great Spotted Woodpecker. There were also significant relationships between Starling numbers and the woodpecker daily nest survival and first-egg dates at the local and national scale. With the decline in Starling numbers, cases of interference are no longer reported. Conclusion Up to the 1980s, when Starling numbers were high, nest-site interference was a significant cause of nest failure and delayed breeding in the Great Spotted Woodpecker and may have been sufficiently high to affect their population and habitat distribution. The decline in Starling numbers in recent decades has led to increased breeding success of the woodpeckers and may have allowed them to expand their breeding distribution into less wooded habitats.

Changes in circadian LH-secretion patterns and annual gonadal cycles in the male European starling (Sturnus vulgaris)

An analysis of the circadian and circannual patterns of luteinizing hormone (LH) secretion in male European starlings (Sturnus vulgaris) held in outdoor aviaries is presented. On the basis of six daily time points, eight calendar dates, and seven individuals per sampling unit, we present a mathematical model developed to compare the two temporal patterns of secretion, the circadian and the circannual one. The superposition of four orthonormal trigonometric base functions, plus a constant, is used to examine the daily fluctuations. The contribution of the second harmonic was not the same at each calendar date. From the subsequent regression functions, hourly estimates of LH concentration were calculated and used to construct circannual cubic splines and an LH(t,T) function over the whole year. The model features indicate strong circannual and circadian components in the data. In addition, there appear to be two daily time regions of LH secretion: morning and afternoon. In particular, the afternoon maxima occur during photorefractoriness and early gonadal development; the morning maxima at the onset of photoinduction and late gonadal development. At the peak of gonadal activity (end of April), the highest LH levels occur during the photic input phase. It appears, then, that the circadian acrophase of LH secretion in male starlings fluctuates over the annual cycle of gonadal activity in a highly predictive and biologically interpretable manner.

Evidence for sexy sons in European starlings (Sturnus vulgaris)

The “sexy son” hypothesis suggests that females obtain future fitness benefits from mating with polygynous males through the inheritance by their sons of traits contributing to mating success. We tested this hypothesis in the facultatively polygynous European starling (Sturnus vulgaris) in two ways. We first compared sons of monogynous and polygynous free-living males for their abilities in nest site acquisition and female-directed behaviors in controlled aviary tests. We then investigated eggs laid in monogynous and polygynous matings for concentrations of maternal steroid hormones that could affect behavioral differentiation of sons. Sons of polygynous fathers defended more nest boxes and produced more courtship song than sons of monogynous fathers. Mean concentrations of maternal androstenedione (A4), 5α-dihydrotestosterone (DHT), testosterone (T), and 17β-estradiol (E) in yolks were not affected by mating status. However, the within-clutch pattern of A4 depended on mating status, with higher concentrations in last than in first eggs of clutches of monogynous but not polygynous matings. These results suggest that (1) sons may inherit from their fathers behavioral qualities for the successful acquisition of nest sites and attraction of mates; (2) differential exposure to maternal steroid hormones during development in the egg is unlikely the cause of the behavioral differences between adult sons of monogynous and polygynous fathers; and (3) females adjust the within-clutch pattern of androgen to mating status, possibly in response to the expected contribution of their mate to nestling care.

FEMALE SONG IN EUROPEAN STARLINGS: SEX DIFFERENCES, COMPLEXITY, AND COMPOSITION

Abstract While male song and its functions have been well studied, female song has often been overlooked. In this study, we provide a detailed description of the spontaneous female song in a well-studied northern temperate songbird, the European Starling (Sturnus vulgaris). We compared the song organization, complexity, and composition of female and male starlings housed in large outdoor aviaries. Overall, the general organization was similar in both sexes, and some females sang complex song bouts of more than 30 seconds of uninterrupted song. Although some females were capable of singing the four phrase-type categories typically found in male song bouts (whistle, variable, rattle, and high-frequency phrase types), a significantly lower proportion of females sang all four categories of phrase type as compared to males. Our results also revealed large individual variation in song characteristics among females: repertoire size varied between 11 and 36 phrase types, while average song bout length ranged betw...