Common Starling Sturnus Vulgaris Research Articles

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.

What factors determine where invertebrate‐feeding birds forage in dry agricultural grasslands?

Increases in the intensity of the management of agricultural grasslands over the past 50 years have reduced plant species diversity in swards and increased uniformity in structure through changes in fertilizer regimes, grazing and mowing practices. These factors, as well as increased disturbance and trampling, have reduced the number and diversity of forbs and thus the diversity and abundance of invertebrates, in particular of foliar species. Associated with these changes in management, there has been a large decline in the abundance of many species of farmland birds in pastoral areas and more local extinctions compared with arable areas. To understand the impact of these management changes on bird populations, and design measures to reverse the declines, it is necessary to identify the key factors influencing bird usage of fields. We review results from five studies, which have related fertilizer and grazing management to bird usage of grass fields. Species that fed on soil invertebrates tended to show a positive response to the amount of nitrogen fertilizer added and increased grazing pressure, although there was a high degree of correlation between these two variables. In summer, many species, including corvids, Common Blackbird Turdus merula, Common Starling Sturnus vulgaris, Pied Wagtail Motacilla alba and Hedge Accentor Prunella modularis, showed a negative relationship with sward height, and in winter more species showed a positive relationship with bare ground. Taller sward heights are associated with a greater abundance and diversity of bird invertebrate food resources, and accessibility of food items or a lower risk of predation (actual or perceived) are likely to be the reasons for birds choosing to forage on shorter swards and in areas with more bare ground. Birds feeding on soil invertebrates were found to be generally tolerant of modern management practices that maintain short swards short, as accessibility to the soil has been increased. Species that feed on foliar invertebrates or forb seeds have been affected negatively by modern grassland agricultural practices.

A record of the Common Starling Sturnus vulgaris in Darwin, Northern Territory

A record of the Common Starling Sturnus vulgaris in Darwin, Northern Territory

Plumage Condition Affects Flight Performance in Common Starlings: Implications for Developmental Homeostasis, Abrasion and Moult

Variation in length and asymmetry of wing primary feathers can arise from a breakdown of developmental homeostasis, feather abrasion and incomplete growth during moult. Indirect predictions have been made concerning the impact of primary length and asymmetry on the flight ability of birds, but they have not been explicitly tested. Here we provide evidence from both natural variation in primary feather condition and experimental manipulations of primary feather length and asymmetry to indicate that these factors influence aspects of flight performance in the Common Starling Sturnus vulgaris. Damaged and incompletely grown primary feathers reduce escape flight performance. Experimentally reduced primary lengths reduce take-off speed; increased primary asymmetry decreases aerial manoeuvrability. A comparison of the experimental and natural plumage data indicates that birds may be able to adapt to a change in wing morphology, perhaps reducing the effects of feather loss or damage on flight. The results from this study indicate that primary feathers are under strong stabilising selection to maximise developmental homeostasis and reduce feather asymmetry. These findings are also of ecological importance to the damageavoidance and moult strategies of these birds. This is the first experimental evidence to indicate a quantitative reduction in flight performance with feather lengths and asymmetries typical of those observed during flight feather moult and feather damage in any species.

Comparative Mechanics of Bill, Claw and Feather Keratin in the Common Starling Sturnus vulgaris

The Vickers microhardness of non-melanic keratin was measured from the bills, claws and outer primaries of Common Starlings Sturnus vulgaris. Highly significant differences in hardness were found between all three keratin types. Bill keratin was the hardest and feather keratin the least hard; the relative molecular weight of the different keratin types may explain these differences. Indentation hardness can be used as a measure of the competence of a material to resist abrasive wear so it is likely that the three keratin types differ in their competence at resisting abrasive wear.

The Breeding Bird Communities of Three Canberra Suburbs

SummaryLenz, M. (1990). The breeding bird communities of three Canberra suburbs. Emu 90, 145–153.The composition and size of the breeding bird populations of three plots with garden city character in Canberra, Australian Capital Territory, were each estimated for one breeding season between 1978 and 1981 using the modified territory mapping method. The number of territories per 10 ha (abundance) were 58.4 (Ainslie). 56.1 (Hackett) and 91.2 (Aranda). Species numbers in the sample areas were 26 (Ainslie, Hackett) and 20 (Aranda). Territories of introduced species, mainly House Sparrow Passer domesticus (44.8–63.5%), Common Starling Sturnus vulgaris (6.8–23.0%) and Blackbird Turdus merula (1.27.6%), comprised between 71–79% of the total number of territories. The only dominant native bird species was the Silvereye Zosterops lateralis (5.9–10.3%). 40–69% of all bird species ranked as rare (each < 1 % of the total population). The abundances of native bird species, excluding the Silvereye, were 5.9 T/10 ha in Ainslie, 8.5 T/10 ha in Hackett and 18.9 T/10 ha in Aranda, probably reflecting the extent of native trees and shrubs in streets and gardens. In Ainslie, the vegetation was composed largely of exotic species. In Hackett, native trees (eucalypts) were more common but distributed unevenly. In Aranda, native vegetation dominated, many trees had been retained from the original woodland. Aranda supported a significantly higher population of exotic birds (65 T/10 ha) than Ainslie (46.5 T/10 ha) and Hackett (44.2 T/10 ha); many cavities in the original eucalypts provided House Sparrows and Common Starlings with more nest sites than were available in the other plots.

Origin, Structure, Molt, and Dispersal of a Late Summer Red-Winged Blackbird Population

and feed there on seeds of aquatic plants; they also make feeding raids on nearby grain fields. Often they are joined by common grackles (Quiscalus guiscula), brown-headed cowbirds (Molothrus ater), starlings (Sturnus vulgaris), and bobolinks (Dolochonyx oryzivorous). In many areas where they congregate at this season of the year, red-winged blackbird roosting populations are composed mostly of birds that have bred locally, and their offspring. The origin, structure, and dispersal of a typical late summer redwinged blackbird population, and the relationship of molt to migration were studied during parts of 5 summers (1958 through 1962) at the Patuxent River marsh, Maryland.