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Variation in the developmental timing of flight-feather growth in nestling birds
No full textThe timing of primary-feather development in relation to growth in body-mass varies considerably between altricial species. This variation relates, at least in part, to differences in nesting habits: species nesting in relatively well-protected nest sites, such as holes, start primary-feather development later than altricial species using open-cup nests. For the latter \u27open-nesting\u27 species, the timing of primary-feather development also tends to show an allometric correlation with adult body-size. Since primary-feather development takes longer, relative to growth in body-mass, in small species than in large ones, these data suggest that, for small species, there will be an important selective advantage in using relatively secure nest sites
Nest-site fidelity of Arctic terns Sterna paradisaea in a managed environment exposed to benign human activity
Full text link\ua9 2024 The Author(s). Wildlife Biology published by John Wiley & Sons Ltd on behalf of Nordic Society Oikos. Human activity near seabird colonies is often equated with disturbance. Coping with human disturbance is a critical task in the management of seabird colonies where human access is an issue. Nest-site fidelity and breeding dispersal were characterised in an Arctic tern population exposed to a high level of benign human activity from resident conservation staff and public visitors. The annual return rate of nesting birds was 90% over the 10-year study period. Nest-site fidelity was high with most birds returning to the same 2
7 2 m square in subsequent years, in particular to nest sites that were against walls and exposed to a high level of human activity at close range. This indicates that human activity was not a deterrent to nesting by Arctic terns. Breeding dispersal to other nearby colonies was low, except when related to colony abandonment. The data suggest that benign human activity from resident staff and public visitors can be a positive benefit, both within and across years, to Arctic tern colonies. Managed public access could be considered an effective management tool for Arctic tern conservation, as well as seabird colonies more widely
Pair bonds during the annual cycle of a long‑distance migrant, the Arctic Tern (<em>Sterna paradisaea</em>)
Full text linkBackground The extent to which pairs remain together during the annual cycle is a key question in the behavioural ecology of migratory birds. While a few species migrate and winter as family units, for most the extent to which breeding partners associate in the non-breeding season is unknown. The Arctic Tern has one of the longest migrations of any species, and the aim of this study was to establish whether or not partners remain together after breeding. Methods Leg-mounted geolocators were fitted to breeding pairs of Arctic Terns nesting on the Farne Islands, Northumberland, UK. The devices were recovered for analysis the following year. Results Analysis of data for the six pairs which returned the following year show that partners departed from the colony at different times after breeding and migrated independently to different Antarctic regions. Partners also departed from the Antarctic and turned to the breeding colony independently. One third of the pairs divorced on return. Conclusions For long-distance migrants reliant on unpredictable foraging opportunities, it may not be viable to remain as pairs away from the breeding colony. Synchrony in arrival times at the breeding colony may maximise the chance of retaining a familiar partner, but could be affected by environmental factors in wintering areas or along migration routes
Brood-patch development and female body mass in passerines
No full textThe brood patch in passerine birds is an area of thickened and vascularised skin which develops to facilitate incubation. In the British Trust for Ornithology Ringing Scheme, the stage of brood-patch development is recorded using a six-point scale. Since eggs represent a substantial proportion of adult body mass, the body mass of females may vary as a result of ovarian growth, egg laying and incubation. The aim of this study was to test the hypothesis that the body mass of females varies in relation to brood-patch stage, using ringing data collected at a single site in the UK during the breeding season. The data analysed were for females of four species of summer migrants and six resident species. Data for a migrant species in which the males also incubate and develop brood patches were also analysed to compare males and females at equivalent stages. In eight of the 10 species studied, female body mass was highest at a brood-patch score equivalent to a pre-incubation stage. There was a clear seasonal decline in female body mass for birds with fully developed or regressing brood patches. Comparisons of standardised body mass between species suggests that brood-patch data could be used to measure annual and regional variation in breeding phenology. \ua9 2010 British Trust for Ornithology
Distinct properties of fenretinide and CD437 lead to synergistic responses with chemotherapeutic reagents
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