Integrated population monitoring: detecting the effects of diverse changes

The use of constant effort mist-netting to measure between-year changes in the abundance and productivity of common passerines

“…1 Annual indices of population size are provided by the Common Birds Census (CBC) and Waterways Birds Survey (WBS), 2 and will in future be provided by the new Breeding Bird Survey. 3 Annual measures of clutch size and nesting success are provided by the Nest Record Scheme 4,5 and survival rates of adult and immature birds can be estimated from ringing recoveries. 6,7 Using changes in catch sizes at standardized mist-netting sites, the Constant Effort Sites (CES) Scheme aims to complement other BTO monitoring schemes by providing estimates of between-year changes in adult population size and annual indices of productivity (the proportion of juveniles in the catch) for a range of common passerine species.…”

“…However, provided that trapping efficiency is constant in each year, the percentage of juveniles caught should constitute a valid index of changes in productivity. While nest record cards provide a means of monitoring annual variations in nesting success, 4 the CES productivity index should integrate variation in nesting success, the number of breeding attempts and some component of post-fledging mortality.…”

The Decline of the BullfinchPyrrhula pyrrhulain Britain: is the Mechanism Known?

“…The BTO's Common Bird Census (CBC), which first identified a decline, monitors abundance (Marchant et al 1990), the Nest Record Scheme provides historical data on Bullfinch breeding success (Crick & Baillie 1996), recoveries of dead birds ringed under the Ringing Scheme supply information on survival rates (e.g., Greenwood et al 1993) and the Breeding Bird Atlases tell us about geographical distribution (Sharrock 1976, Gibbons et al 1993). …”

Changing demography and population decline in the Common Starling Sturnus vulgaris: a multisite approach to Integrated Population Monitoring

“…The British Trust for Ornithology (BTO) has developed such a scheme to investigate the demographic and environmental factors affecting the population changes of breeding birds in Britain (Baillie 1990, 2001, Greenwood et al . 1993).…”