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Breeding birds must choose habitat at a multiple scales, from landscapes to nest sites. It is important to understand how birds make these decisions and the relationships between these choices and breeding success. Over 3 years, we studied nest-site selection of the Ringed Warbling-Finch (Poospiza torquata) in the semiarid Chaco of Argentina at the scales of the landscape, nest patch, and nest site. At the landscape scale, Ringed Warbling- Finches established nesting territories in shrub-grassland exclusively. Within shrub-grassland, nest patches and nest sites selected differed in few attributes of vegetation cover from patches and sites that were available, and those differences varied from year to year. Only in the year when brood survival and breeding success were lowest did features of sites of successful and depredated nests differ clearly. The Ringed Warbling-Finch selects features of nesting habitat at the landscape, nest-patch, and nest-site scales. Implications of choices at the scales of nest patch and nest site appear to vary by year, but the presence of shrubs, particularly Geoffroea decorticans and Ziziphus mistol, was most frequently important. The species appears to be plastic in its selection of nest patches and nest sites, perhaps because these choices do not lead to consistent selective advantages. [ABSTRACT FROM AUTHOR]

The article presents a study concerning the supplementary food consumption of birds utilizing the stable-isotope analysis. This method is used in quantifying the amount of supplemental food provided to birds and is used in determining the full effects of these food on their diet. It also aids in the accurate assessment of the effects of an increased food supply on ecology and animal behavior. Meanwhile, the findings reveal that supplementary food consumption of birds varies from one another.

The article presents a study that investigated the reciprocal tradeoffs between molt and breeding in adult Black-footed Albatrosses. It states that the study found that Black-footed Albatrosses have an intrinsic cycle of primary replacement and those having middle primaries in their third year of use have lower breeding success. It reveals that the inability of many large birds to replace all their flight feathers annually creates potential life-history tradeoffs between breeding and molting.

The article presents a study that compares the morphology of immature-and mature-plumaged males of the Saffron Finch or Sicalis flaveola. Study shows that immature-and mature-plumaged males were similar in morphology while females paired to mature-plumaged males are having bigger bill height and weight. It is noted that there are no differences between females paired to each category of male in any biologically meaningful variable.

The article presents a study that evaluates two ecological hypotheses explaining the cluster formation during reproduction of the Blue-black Grassquit or Voltainia jacarina. Study shows that territories were clustered in habitat with more food and a more complex vegetation structure. It is noted that the aggregation of Blue-black Grassquit territories can be associated with habitat heterogeneity.

The article presents a study that examines the relationship of carotenoid-based plumage coloration to mating and reproductive success in a migratory songbird Setophaga ruticilla or American Redstart. Study shows no relationship between carotenoid-based coloration and within paternity. It is noted that males having less saturated orange flanks sired more total young compared with those more saturated.

The article presents the study conducted regarding the success of breeding the migratory songbirds in the harvested boreal forests in northwestern Newfoundland and Labrador. The study aims to determine the impact of forest harvest on the success pf passerines breeding and the natural harvesting on the harvesting consequences. The result from a series of nests and banded hatch-year birds monitoring shows that spatial and temporal heterogeneity have complex interactions in the forest harvest and the daily survival of nests are significantly associated to the harvest proportion.

The article focuses on the demographic performance to breeding-site location in the King Penguin. It highlights the central periphery model of the King Penguin colony in the subantarctic Crozet Archipelago. It also states that the center of the colony gives the highest rate of predation and parasitism of penguins in the breeding season. It is believed that penguins breeding in the center of the colony obtained the same breeding success as those at peripheral locations. Significant factors in determining individual survival and reproduction of long-lived birds were also discussed by the author.

Whereas demographic performance increases with experience, little is known about the experience-related response of demographic performance to environmental variations. In long-lived birds, theoretical studies consider experience-related differences in performance to be greater under more restrictive conditions, but this has rarely been tested. We tested this hypothesis on the White Stork (Ciconia ciconia), using a long-term capture-mark-recapture dataset. We studied the demographic response of a population from Western Europe to climate by analyzing adult survival and breeding success as a function of breeding experience. Birds reproduced less well during their first breeding event than during subsequent ones, suggesting that they undergo a learning process. In addition, high mortality in storks inexperienced at breeding may reflect an important cost associated with the first reproduction event. Presumably, birds subject to the highest cost of reproduction would die during the ensuing winter, with selection favoring birds able to maximize their survival. The first reproductive occasion could be considered a key event for White Storks, for whom mean breeding performance as well as survival probability increased over time in the population, likely as a result of a combination of learning and selection processes. Interannual variation of breeding success was partly explained by spring precipitation on the breeding ground, reflecting environmental variation. By contrast, winter conditions in the Sahel could not explain fluctuations of the survival. Contrary to our predictions, over this 12-year study, inexperienced individuals seemed to be affected by climatic fluctuations, regardless of their severity, in the same manner as experienced ones. [ABSTRACT FROM AUTHOR]

We studied the impacts of low density, exurban housing developments on Wood Thrushes (Hylocichla mustelina) breeding in small forest fragments in two regions of rural southern Ontario. In both regions, Wood Thrushes breeding in woodlots with embedded houses (housing penetrating the forest border) experienced significantly higher rates of parasitism by Brown-headed Cowbirds (Molothrus ater) than Wood Thrushes breeding in woodlots with adjacent houses (houses within 100 m of the forest edge), or undeveloped woodlots (no houses within 100 m of the forest edge). Wood Thrushes breeding in Peterborough area woodlots with embedded or adjacent houses experienced significantly increased rates of nest predation compared to Wood Thrushes breeding in undeveloped woodlots. This increased nest predation resulted in significant reductions in seasonal productivity in developed woodlots. No increase in nest predation was experienced by Wood Thrushes nesting in developed woodlots in the Ottawa region. The effects of housing developments appear to be region-specific and may depend on other factors influencing the overall abundance of cowbirds. [ABSTRACT FROM AUTHOR]

To study the patterns and determinants of philopatry and breeding dispersal in the Tree Swallow (Tachycineta bicolor) we analyzed the records of 356 males and 1459 females captured in more than one breeding year around Ithaca, New York. Of these captures, only 4% of male and 14% of female breeders dispersed to a new site for breeding. With our combination of intensive study areas in Tompkins County, New York, and the efforts of volunteer banders throughout New York and surrounding states, we could have detected dispersal in excess of 400 km from the initial breeding site. Randomization tests revealed, however, that breeders dispersed much shorter distances than they could have been detected. Detailed analyses of recaptures in Tompkins County showed that over a 22-km range of distances, the chances of dispersal to a new breeding site declined with the distance from the original breeding site. Females that failed to fledge any offspring were much more likely to disperse than females that reproduced successfully, and the probability of dispersal declined gradually with female age. The spatial scale in which swallows gather and process information appears to be much larger than for passerines that defend all-purpose territories. [ABSTRACT FROM AUTHOR]