Local weather can influence the growth and development of young birds either indirectly, by modifying prey availability, or directly, by affecting energetic trade‐offs. Such effects can have lasting implications for life history traits, but the nature of these effets may vary with the developmental stage of the birds, and over timescales from days to weeks. We examined the interactive effects of temperature, rainfall and wind speed on the mass of nestling and fledgling Barn Swallows Hirundo rustica both on the day of capture and averaging weather across the time since hatching. At the daily timescale, nestling mass was negatively correlated with temperature, but the strength of this association depended on the level of rainfall and wind speed; nestlings were typically heavier on dry or windy days, and the negative effect of temperature was strongest under calm or wet conditions. At the early lifetime timescale (i.e. from hatching to pre‐fledging), nestling mass was negatively correlated with temperature at low wind speed. Fledgling body mass was less sensitive to weather; the only weather effect evident was a negative correlation with temperature at the daily scale under high rainfall that became slightly positive under low rainfall. These changes are consistent with weather effects on the availability and distribution of insects within the landscape (e.g. causing high concentrations of flying insects) and with the effects of weather variation on nest microclimate. These results together demonstrate the impacts of weather on chick growth, over immediate (daily) and longer term (nestling/fledgling lifetime) timescales. This shows that sensitivity to local weather conditions varies across the early lifetime of young birds (nestling–fledgling stages) and illustrates the mechanisms by which larger scale (climate) variations influence the body condition of individuals.
Climate‐driven increases in spring temperatures are expected to result in higher prey availability earlier in the breeding season for insectivorous birds breeding in wetland habitats. Predation during the incubation phase is a major cause of nesting failure in open‐nesting altricial birds such as the Eurasian reed warbler. The nest predation rate in this species has recently been shown to be substantially reduced under conditions of experimentally elevated invertebrate prey availability. Food availability near the nest may be an important determinant of adult incubation and nest defence behaviours during the incubation period. We used two experimental studies to compare incubation behaviour and nest defence in food‐supplemented and unsupplemented adult Eurasian reed warblers during the incubation phase. In the first study we measured nest defence behavioural responses to a taxidermic mount of a native predator (stoat Mustela erminea). In the second study we used temperature loggers installed in nests to measure breaks in incubation as a measure of nest vulnerability. Food‐supplemented birds responded aggressively to the presence of a predator more quickly than those in the unsupplemented group, suggesting they are closer to their nest and can more quickly detect a predator in the vicinity. Food‐supplemented birds also had shorter breaks in incubation (both in terms of maximum and mean off‐bout durations), presumably because they were foraging for shorter periods or over shorter distances from the nest. This study therefore identifies the behavioural mechanisms by which changes in food availability may lead to changes in nest survival and thus breeding productivity, in open‐nesting insectivorous birds.
1. Confirming the presence and location of European Nightjar Caprimulgus europaeus nests is a significant fieldwork challenge in ecological monitoring. Nest sites can be located through direct observation or capture and radio tracking of breeding individuals; however, such work is time consuming, disturbing and costly. 2. Unmanned aerial vehicles (UAV) equipped with thermal sensors may enable rapid survey over large areas by detecting nest locations based on the contrast of relatively warm nests and the surrounding cooler ground. The application of this concept using UAV-mounted thermal sensors was trialled in two upland clear-fell forestry sites in South Wales, UK. 3. Detection trials were undertaken at five known nightjar nest sites to assess optimal timing and flight height for surveys. Nest heat signatures were clear during dusk and dawn, but not during the daytime. Nests were identifiable at flight heights up to 25 m, but flight heights of 12-20 m were optimal for the numbers of pixels per nest. 4. This approach was tested in a field trial of a 17-ha forestry site where the presence and position of nesting nightjars were unknown. An automated transect at dusk and dawn at 15 m flight elevation identified two active nightjar nests and four male nightjar roost sites. Without image analysis automation, the process of manual inspection of 2607 images for 'hotspots' of the approximate size and shape of nightjar nests was laborious. 5. The UAV approach took around 18 h including survey time, processing and ground verification, whilst a nightjar nest finding survey would take 35 h for the same area. The small size of nightjars and the low resolution of the thermal sensors requires low altitude flight in order to maximize detectability and pixel coverage. Low flight elevation requires more consideration of the risk of collision with trees or posts. Consequently, the approach would not be suitable for covering areas of highly variable terrain.
Introduction Primary care-based frailty identification and proactive comprehensive geriatric assessment (CGA) remains challenging. Our Devon-based Primary Care Network has developed and introduced an innovative, community-based IT-assisted CGA (i-CGA) process, which includes advance care planning (ACP). We wished to see if this process could improve effectiveness of ACP in residential care home (CH) residents. Methods/Intervention Interim analysis focused on adherence to ACP-documentation in severely frail residents, comparing groups: Results i-CGA group: 196 residents (16 mild/69 moderate/111 severe frailty); control group: 100(13 mild/31 moderate/56 severe). No significant baseline differences. 100% residents in the i-CGA group had documented resuscitation decisions, vs 72% (72/100) controls: in 97% of both groups (191/196,70/72) to ‘allow a natural death'. 85% (94/111) severely frail i-CGA residents preferred not to be hospitalised. 55% (52/94) died, 90% (47/52) in their CH. Compared to the preceding year, unplanned hospitalisation rates fell:0.86 to 0.68/person years alive. In severely frail control residents, unplanned hospitalisations increased: 0.87 to 2.05/person years alive. 29% (16/56) had no hospitalisation preferences documented. 16/16 died, 25% (4/16) in hospital. 40/56 had documented decisions, not all recent:38% (15/40) wished for admission. Significant group mortality difference was seen: 55% (62/111) severely frail i-CGA residents died compared to 77% (43/56) controls, p=0.0013. Conclusions Proactive primary care-led i-CGA in severely frail CH residents promotes up-to-date discussions regarding preferred place of care and death. Most prefer not to be hospitalised, despite traditionally high rates of unplanned admissions. Our i-CGA/ACP process improves adherence to preferences, reduces unplanned hospitalisations and mortality rates. Progressive i-CGA completion and annual/opportunistic reviews should confer progressive benefits.
The impacts of climate change on natural populations are only beginning to be understood. Although some important changes are already occurring, in the future these are predicted to be more substantial and of greater ecological significance. Insects are a key taxonomic group for understanding the ecological impacts of climate change, due to their responsiveness to environmental change and importance as food for other organisms. Insects are highly sensitive to rising temperatures, changes in rainfall patterns and erratic weather conditions, driving rapid short‐term variations in their abundance, mobility, distribution and phenology. Such variations represent changes in their availability as prey to insectivores, a diverse range of insect‐eating animals that include mammals, fish, amphibians, reptiles and birds. The impacts of these changes on the ecology of insectivores are complex and include population increases or decreases, broad‐scale shifts in distribution, and changes in behavioural traits such as foraging strategy, investment in parental care, and the timing of breeding and migration. Although some insectivorous species are able to respond to – and even benefit from – climate change, those that fail to respond appropriately may struggle to reproduce, disperse and survive, leading to population decline and ultimately, to extinction. Key Concepts Insects are a key taxonomic group in most terrestrial and freshwater ecosystems, providing an important trophic resource for insectivores. Climate change is already causing major shifts in the distribution, phenology, behaviour, abundance and diversity of insect populations, with complex consequences for insectivores. Climate change may benefit some insectivores by increasing food availability and providing more suitable conditions for reproduction. Specific benefits to insectivores include earlier parturition, faster development of juveniles and range expansion. Warmer temperatures may also cause negative impacts on insectivores, through more frequent and intense heat waves and reduced water availability in arid environments. The negative impacts are expected to be more severe for taxa that are less able to disperse or migrate to escape unfavourable conditions, and thus less able to shift range to track the changing conditions. The timing of biological events (phenology) will be affected – primarily by advancing the dates at which insects become active in spring and extending the length of the active season of insects in temperate and boreal regions. Important gaps in our knowledge remain, for example despite the large biomass and species richness of insects in the tropics the impacts of climate change on tropical insectivores remain largely unknown.
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