The aim of this study was to examine the effects of forest fragmentation on the ability of parent birds to provide their young with an adequate food supply. To examine whether prey population densities of the great tit (Parus major L.) and the blue tit (P. caeruleus L.) vary between study areas in different forest size classes we compared provisioning rates and chick diet and related these parameters to breeding success. We filmed 217 nests over two breeding seasons and collected data on frass fall as a general estimate of caterpillar availability. Nests which were attended by none or one parent only during filming (n = 46) were excluded from the analyses. In both years and for both species feeding rates were highest in the smallest fragments and lowest in the large forest. There was also a suggestion that differences in feeding rates between areas vary between years. We found no consistent tendency for prey size to change with forest size, although both species brought slightly smaller prey items to the nest in the smallest forest fragments and feeding rates correlated negatively with prey size. Caterpillars were the main item fed to nestlings, in both species. We found no evidence to suggest that either frass fall or the proportion of caterpillars in the diet varied with forest size. There was also no correlation between mean frass fall and the total number of caterpillars brought to the nests, in either species. Breeding success, as measured by clutch size, brood size, fledging weight and fledging success, did not differ between the small fragments and the large forest, in either species. There was also no relationship between provisioning rate (as concerns volume of prey fed to nestlings and the quality of chick diet) and breeding success parameters. In conclusion, this study does not suggest suboptimal foraging or breeding conditions in small fragments compared to a nearby large forest, for either species.
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http://dx.doi.org/10.1007/s004420050476 | DOI Listing |
Ann Bot
December 2024
Department of Agronomy, University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Background And Aims: Fire-released seed dormancy (SD) is a key trait for successful germination and plant persistence in many fire-prone ecosystems. Many local studies have shown that fire-released SD depends on heat and exposure time, dose of smoke-derived compounds, SD class, plant lineage and the fire regime. However, a global quantitative analysis of fire-released SD is lacking.
View Article and Find Full Text PDFAnimal Model Exp Med
December 2024
Frontiers Science Center for Molecular Design Breeding (MOE), State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, China.
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View Article and Find Full Text PDFVet Rec
December 2024
Hill & Mountain Research Centre, Scotland's Rural College, Crianlarich, UK.
Background: The breeding population of the red-billed chough (Pyrrhocorax pyrrhocorax) in Scotland has fallen in recent years, with all breeding pairs now confined to the Hebridean islands of Islay and Colonsay. Demographic studies have shown that a significant factor in the population decline on Islay has been reduced survival from fledging to 1 year of age (juveniles). Understanding the significance of infectious and non-infectious diseases in chough mortality is crucial to the development of successful management strategies aimed at conserving breeding populations of choughs in Scotland and elsewhere.
View Article and Find Full Text PDFAbstractSenescence is ubiquitous yet highly variable among species, populations, and individuals, for reasons that are poorly understood. It is not clear how environmental conditions affect senescence, especially in the wild. We explored the influence of environment on the degree of laying date age-specific variation and reproductive success senescence in wild blue tits.
View Article and Find Full Text PDFAnim Cogn
December 2024
Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, E-18071, Spain.
The house sparrow (Passer domesticus) is a gregarious generalist species, which makes it a good model for studying play. However, play has not been described for this species so far. We describe play behaviour in house sparrows for the first time, quantifying all play and play-related behaviours, searching for differences between the different sexes and ages, the possible association with reproductive success and the diffusion of this behaviour in the population.
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