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We used clearly defined measures of weather and time of day to determine their impacts on the number of bird species recorded in 5439 area-search surveys of 142 one-hectare sites in open temperate woodlands. Surveys recording the highest number of species spanned the full range of times of day and weather conditions. For our full dataset, the number of species recorded dropped by 16% at higher wind speeds (>20 km/h), 0.8%/h after sunrise (or 7.4% in the afternoon compared to morning), and 0.5% per degree temperature increase, but was unrelated to cloud cover. Resampling our full dataset, we separated impacts of effort from weather and analysed scenarios which might arise with time or budget constraints. Dawn surveys were less affected by time and weather, and recorded more species than other scenarios per unit of effort, especially at species-rich sites. We demonstrate that setting thresholds for these variables is not warranted if this reduces sample size in a study. Conversely, if researchers are restricted to a fixed number of surveys, then our data highlight that thresholds may be used to optimise results by avoiding periods when less productive conditions, particularly winds >20 km/h, prevail. [ABSTRACT FROM AUTHOR]

Animal research guidelines recognise that trapped animals can potentially be subjected to heat stress, but recommendations are limited to avoiding exposing traps to weather extremes. Intuitively, shading metal box traps should be beneficial in warm to hot climates. Temperatures inside metal box traps were measured within traps located in direct sunlight concurrently with ones covered with artificial shading. Additionally, comparisons were conducted in continuous shade cast by ground-cover vegetation, and in stippled sunlight under an artificial lattice. Deep continuous shade from vegetation was most effective and able to keep traps within 5°C of ambient. Artificial shading using dark shade cloth could actually elevate trap temperatures above that in uncovered traps when exposed to direct sunshine. Reflective foil insulation cover not only provided rain protection for traps but was the most effective shading method trialled for reducing both the rate at which traps heated after sunrise and the maximum temperature reached during the day when exposed to direct sunshine. The use of foil sleeves can provide an extra level of protection from excessive heat exposure to trapped animals, keeping trap temperatures as much as 15°C lower than unprotected traps. [ABSTRACT FROM AUTHOR]