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In this review the influence of ectoparasites on nestlings' of some hole-nesting birds is discussed, especially the impact on nestlings' mortality or condition.
The paper analyses the effect of egg dimensions (volume, breadth, and length) on the growth and development of Tree Sparrow nestlings on successive days of life. Egg size did not influence nestling mortality. It was found that for most days of nestling life, the mean volume and breadth of eggs were positively correlated with the mean mass of nestlings in the nest. Similarly, the deviation of the volume and breadth of a particular egg from the mean egg volume and breadth in the clutch was positively correlated with the deviation of nestling mass from the mean nestling mass in the nest. Nestling growth and development in terms of asymptotic mass (g), maximum growth rate (g/day), tarsus length, and longest remex length were also positively correlated with egg size. The effect of egg size was particularly pronounced in the period of termination of intensive growth rate, development of thermoregulation, and feather development. It is possible that larger eggs contain more microelements, hormones, antioxidants, and vitamins.
Several studies have suggested dietary segregation between nestling and adult birds resulting from both dietary requirements of offspring and distance to the foraging sites. We examined the diet in terms of composition and dimension, as the weight, habitat and taxonomy of prey in nestling and adult male and female Bluethroats Luscinia svecica spp. cyanecula at a recently colonized area in a mosaic of wetland (with sewage water) and terrestrial habitats in south-west Poland. On the basis of faecal samples collected between 2009-2012 from several broods and 94 adults, we found that nestlings had significantly lower diet diversity, consisting of heavier prey items. Comparing the proportion of seven major food types (order of insects/invertebrate class) we showed that the diet composition of adult and nestling Bluethroats differed significantly. The diet of nestlings contained significantly more soft-bodied prey items, namely Diptera and Lepidopteran larvae, and significantly fewer Coleoptera and Hemiptera. Furthermore, since adult showed marked decrease (contrary to young Bluethroats) of diet diversity and number of prey in the progress of the breeding season, hence our entire findings can imply that nestlings are fed in a selective manner receiving more profitable (soft-bodied and terrestrial) prey, and adults adjust their diet consuming less profitable (more chitinized and smaller) prey. This ultimately suggests the partial dietary segregation between nestling and adult birds, both in the term of size (biomass) and composition of prey. The use of a broad spectrum of food items and various prey types, and particularly the low dependence of nestlings on aquatic insects, suggests that Bluethroats have very plastic dietary requirements, which is most likely a factor facilitating the recent population recovery and adaptation to ecotonal zones between moist/wetland and terrestrial habitats with abundant moist soil, in newly settled areas of Europe.
Females of many socially monogamous bird species engage in — or even actively seek — copulations outside their social pair bond. However, in socially monogamous birds with low breeding abundance, such as the Red-backed Shrike, extra-pair paternity (EPP) was thought to be an exceptional and random incident. Drawing on samples collected in an unusually dense Red-backed Shrike population in the Czech Republic, we show through DNA microsatellite typing that among 65 chicks from 15 nests, 10 individuals (26.5%) had been sired by males other than the nest-attending social mate. All 10 extra pair young were of male sex. In all cases, genetic fathers of extra pair young stemmed from neighbouring territories. Extra pair fathers had significantly longer tarsi than social mates, indicating that female choice was a function of age-class dependent male body size. Our findings support sex allocation theory, which suggests that promiscuous females mating with higher quality males should produce mostly sons.
Plumage colour is classified as pigmentary or structural, depending on whether it is caused by pigments or by feather microstructure. However, recent findings indicate that carotenoid-based plumage colouration also reflects at UV-blue wavelengths and that the underlying structure is related to the reflectance properties of the yellow feathers. Thus, yellow plumage is based on interactions between structural and pigmentary components. This study investigated the relationships among the vegetation structure of breeding territories, both components of plumage colour, T-cell- mediated immune response and body mass of nestling Great Tits Parus major. By using a model of avian visual perception, we found that, while plumage yellowness was associated with mature vegetation, plumage brightness and UV- blue reflectance were related to immature habitats in territories. We noted considerable variability in the development of carotenoid-based colour components under different environmental conditions, as plumage yellowness, but not brightness or UV-blue reflectance, depends on the availability of carotenoids, which is assumed to be high in mature territories with high food abundance. Territorial features denoting mature territories were also related to high body mass and immune response in nestlings, but none of the colour components were related to these variables of the vegetation structure, suggesting that habitat quality is related to nestling body mass and immune response through mechanisms different from those through which it is related to colour.
Dependencies of heavy metal concentrations in organs of Tree Sparrow nestlings (Passer montanus), and growth and histopathological changes of these organs in polluted and control (unpolluted) environments of Białystok (53°06' N, 23°10' E; 300,000 inhabitants, NE Poland) were investigated. The highest concentrations of Fe, Zn, Cu, Cd and Pb were found in the liver and kidneys in both environments. Pb concentrations in the polluted areas were highest in the lung and spleen. Comparatively high amounts of Cu and Cd accumulated in pectoral muscles. In all organs the highest concentrations of Fe and lowest of Cd and Pb were found in polluted areas compared with unpolluted ones. Differences of Zn concentrations in nestling organs from both areas were not significant. Concentrations of investigated elements increased during postembryonal development in all organs in both areas. Interactions between Fe and Zn with Cd and Pb were most commonly noticed in the liver, kidneys and lung. Nestlings from the unpolluted areas reached maximum body mass at about the 12th day of their life and biomass gain was more intensive compared with nestlings from the polluted areas, which reached their maximum body mass just before flight from the nests. They grew slower and body mass gain took place until the time of flight from their nests. Differences in the growth and development of nestlings from both areas can be explained by the concentration of toxic heavy metals in the polluted areas. Histopathological changes of nestlings, mainly in their livers, kidneys and lung, were found in both areas. The level of these changes was more intensive in the polluted areas. This state should be connected with the higher concentration of toxic heavy metals in these areas and also with the heredity of diseases causing histopathological abnormalities.
Female white-footed mice Peromyscus leucopus (Rafmesque, 1818) and their dependent offspring were monitored in nest boxes to determine the extent and causes of nest mortality. The mortality of dependent young was high (561 of 838; 66%) and variable among years. Most mortality involved the loss of entire litters (112 of 183 litters; 61%), with half of these losses attributed to the death of lactating females before the young were weaned (59 of 112 litters; 53%). Most mortality was from unknown causes, although infanticide, energetic constraints and prédation were identified in a small number of cases. Prédation is likely the major source of mortality in this population.
The evolution of organisms leads to the elimination of behaviors that are costly in terms of energy. One of such behaviors in the Tree Sparrow Passer montanus is the autumn display during which these birds construct nests. The purpose of this paper is to find out if this behavior is a part of the strategy for winter survival.The study of Tree Sparrows was conducted near Warsaw, Central Poland. During the breeding season, nest boxes were checked to record the presence of Tree Sparrow nests. Before the autumn display, breeding nests were dyed in order to identify nest material added in the period of autumn display. Nestlings in nest boxes, juveniles, and adults captured in mist-nets were banded with different combinations of color bands to identify their age during visual observations in the period of autumn sexual display. Juveniles and adults caught in mist-nets were classified as molted or not molted birds. In winter, nest boxes were checked to catch the birds roosting in them at night. Autumnal sexual display in Tree Sparrows is similar to the spring display. Both adults and juveniles leave the breeding colony in August and return after molt. They form pairs, copulate and build nests in fall. The autumn display is continued from the first ten days of September to early November. The number of Tree Sparrows participating in the autumn display increases with the percentage of the birds that completed molt in the population. In the first half of September, 16% of the population completed molt, while 99% in mid-October. On the average, adult birds formed pairs on 11 September (SD: 7.7 days), and juveniles on 17 September (SD: 8.0 days). Nest construction was started, on the average, 14.2±8.7 days after pairing. The advance in nest building was dependent on the time of pair formation. Intensive nest building took place in the last 10-days period of September and in October. Early in November, nest building ceased with the onset of cool weather. The last birds to pair did not construct complete autumn nests and in winter they roosted in shrubs or in tree crowns . The building of autumn nest as a consequence of the autumn display, serving as a roosting place in winter, can be a consequence of natural selection promoting this behaviour.
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