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Segregation in sympatrically nesting red-winged starling Onychognathus Morio (L.) and European Starling Sturnus Vulgaris L.

Kopij G.

Polish Journal of Ecology

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2009

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Vol. 57, nr 3

589-595

EN

If two related species come into contact, it could be expected that, in order to coexist, they will either shift their niches apart from each other or one species will replace the other in the course of ever growing competition. Recently, two starling species, the indigenous Red-winged Starling and the exotic European Starling, came into contact in some places in Lesotho (southern Africa). In this paper, some breeding parameters of these species have been compared in an area of their co-occurrence. Studies were carried out in an urbanised habitat in Lesotho, in four consecutive breeding seasons (August-March) during the years 1998-2001. The average density of the Redwinged Starling was 13.8 pairs 100 ha[^-1], while that of the European Starling was 9.3 pairs 100 ha[^-1]. The proportion of the Red-winged Starling to European Starling breeding pairs (1.0:0.7) was strikingly constant over the four consecutive breeding seasons. Most Red-winged Starling breeding territories (78%, N = 56) were located within builtup areas, while most European Starling territories were located either within built-up areas (25%) or on the border of built-up areas and open areas (59%, N =41). Most Red-winged Starling nests (96%) were situated in buildings (N = 46), while European Starling nests were located both in tree holes (43%) and in buildings (57%, N = 28). Both starling species show high nest site tenacity. The Red-winged Starling daily activity pattern during the nestling phase differed considerably from that of the European Starling. Although both starling species do not overlap their feeding niches and daily and seasonal activities, their sympatric occurrence in urbanised habitats may be limited, if suitable nesting sites are lacking.

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Lack of synchrony between breeding in two neighbouring starling (Sturnus vulgaris L.) populations in New Zealand : evidence of no regional effect of the ENSO?

Flux J., Bull P., Zduniak P., Tryjanowski P.

Polish Journal of Ecology

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2009

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Vol. 57, nr 2

363-369

EN

Weather and climatic conditions may impact on many aspects of bird populations, including population size, the timing of breeding and synchrony between these variables in local populations. We examined synchrony in population size and the laying date of two starling Sturnus vulgaris populations 25 km apart, at Ohau and Belmont, in New Zealand. Data were collected in nest-boxes in both study plots from 1970 to 2003. Additionally we investigated possible relationships with a large geographical climate index, the El Nino Southern Oscillation (ENSO). Starlings at Ohau bred significantly earlier than at Belmont. The difference in the median of year median date of laying the first egg was 3 days. Simultaneously, the percent of nest boxes used by birds was much higher in Ohau (86%, SE = 4.1) than in Belmont (52%, SE = 2.9). However, we did not find a significant relationship between median dates of laying and the percent of nest boxes used by birds in each breeding season in the two populations. Furthermore, we found no influence of ENSO on (potential) synchrony in starlings. breeding parameters. We suggest that lack of synchrony between two close local populations, both in percentage of occupied nest boxes and time of laying, is due to starlings responding to very local conditions, like food availability. We urge future studies to take advantage of spatially close populations.

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Female biometrical characteristics and egg dimensions of the Starling (Sturnus vulgaris L.) in Croatia

Dolenec Z., Kralj J., Mustafić P., Dolenec P.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

545-548

EN

Female biometrical characteristics play an important role in the breeding and contribute to breeding success. The size and shape of Starling (Sturnus vulgaris) eggs in relation to female characteristics were examined. The material was collected in northwestern Croatia (Mokrice region) in 2007. Only first clutches were analysed. Egg length averaged 29.7 mm, egg breadth - 21.2 mm, egg volume - 6810 mm[^3] and egg shape index - 1.41. The inter-clutch CV amounted 6% for length, 3% for breadth, 10% for volume and 6% for egg shape index. The mean female body mass was equal to 81.8 g, wing length - 128.6 mm and female condition - 0.64. No significant correlation was found between the female biometrical parameters like body mass, wing length, female condition and egg dimensions (like egg length, egg breadth, egg volume) or egg shape. Egg length was marginally correlated with egg breadth. Female body mass was significantly correlated with wing length.

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Effect of old nest material in nestboxes on ectoparasites abundance and reproductive output in the European Starling (Sturnus vulgaris L.)

Mazgajski T.

Polish Journal of Ecology

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2007

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Vol. 55, nr 2

377-385

EN

Before breeding, hole nesting birds face the problem of the presence of old nest material from previous seasons in their nest sites. This material fills the cavity, making it shallower, resulting in greater brood vulnerability to predators, as well as creating good conditions for ectoparasite development. As a consequence, this may negatively affect many breeding parameters of hole nesters. However, adult birds may compensate the effect of blood sucking ectoparasites by increasing their feeding rates. It is known that the European Starling Sturnus vulgaris L. can deepen its nest site by removing old nest material. Therefore, a study was conducted to find out whether the presence of old nest material influences ectoparasite abundance in newly built nests, reproductive parameters, as well as nestling. body parameters and feeding rates in this species. An experiment with nestboxes was carried out in two forested areas. Two groups of nestboxes were prepared - one contained old nests from the previous breeding season, and the other group was cleaned with old nests removed. During the breeding season, data on Starling reproduction were collected, i.e. laying dates, clutch size and number of fledglings. Nestling body parameters were measured on the 6th, 9th, 13th and 17th days of their lives. On the 10th and 15th days of nestling life, the number of feedings was counted over a period of 30 minutes. Nests were collected and analyzed for the presence of ectoparasites. It was found that the average number of ectoparasites, both fleas and mites, was greater in nests built on old nest material, and that this number was highly correlated. In further analysis, two possible effects on reproductive output were investigated separately: the presence of old nest material and the abundance of ectoparasites. Clutch size and number of fledglings were smaller in broods from nestboxes containing old nest material, but there was no such relationship to laying dates and nestlings. body parameters (weight, tarsus and wing length). The number of feeding trips on the 10th day of nestling life was higher in .cleaned. nestboxes, but a similar level was achieved by the 15th day in both groups of nestboxes. It was found that ectoparasite abundance did not influence any of the studied parameters of Starling reproduction, i.e. breeding, nestlings. physical condition or number of feedings. This confirmed earlier findings that ectoparasite infestation at a natural level does not affect Starlings. breeding. It seems that the negative effect of the presence of old nest material in nest sites is connected to the costs of site preparation and old nest material removal, which are borne by the females.