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Common Birds Census

The ECN protocol for the Common Bird Census (BC)
code

BC

Protocol file

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Site types that use this protocol

Terrestrial

The Common Birds Census, operated by BTO, was started in 1962 following trials in 1961, with the aim of monitoring bird population numbers, chiefly on farmland where the growing use of agricultural chemicals and the accelerating rate of hedgerow destruction was causing particular concern. Later other habitats, notably woodland, were included in the scheme. CBC uses a mapping method in which a series of visits are made to all parts of a defined plot during the breeding season, and contacts with birds by sight or sound are recorded on large-scale maps. Information from the series of visits is combined to estimate the number of territories found. Maps of the same plot from different years can be used to assess changes in species densities and to relate these to changes in habitats. CBC results also provide indices of population change for those species which are sufficiently numerous to provide large samples when considered across the sites participating in the scheme.

Note: This protocol is no longer compulsory at ECN sites. The Breeding Bird Survey protocol (BB) is now used instead.

Our field activities

SEPTEMBER

This is the last of the busy months in terms of field work at terrestrial sites as the season for monitoring butterflies, frogs, grazing animals and bats draws to an end. In rivers and lakes we sample diatoms for the third time in the year. The usual year-round measurements are also made.

See all this month's field measurements...

Loch Neagh