Bird population changes for the years 1979–80

Bird population changes for the years 1980–1981

“…THIS PAPER PRESENTS the results of the Common Birds Census (CBC) relating to bird population changes between the 1980 and 1981 breeding seasons. As in the previous report (Marchant and Taylor 1981) results are given for 60 species.…”

“…Table VI provides the corresponding data for some scarcer species whose population changes have been assessed by combining data from all habitat types. Indices for 1962-74 are given in Batten and Marchant (1976), while the 1975-80 values appear in Batten andMarchant (1977a, 1977b), Marchant (1978), Hyde (1980a, 1980b) and Marchant and Taylor (1981). Sparrowhawk indices for 1974-79 are given in Marchant (1980).…”

“…To maintain the indices consistently it is necessary that the plots used should be similar to those in previous years. Tables Ito III present some important parameters of the 1980-81 sample; equivalent data for 1979-80 are given by Marchant and Taylor (1981). Batten and Marchant (1976) Table I provides a summary of the plots used, together with their mean areas.…”

Comparing Changes from One Year to the Next in Bird Communities

“…Marchant and Taylor 1981; see also Upton andLampitt 1981, Mountford 1982). One comparison of interest is that between the population levels of a particular species in two successive years.…”

Factors influencing the distribution of MagpiesPica picain an urban environment

“…A subjective assessment of the change in Magpie status throughout the whole country between 1954 and 1963 suggested slight gains in most areas and a move into forestry plantations, suburbs and coastal dune areas (Prestt 1965). More recently, Common Bird Census indices for the Magpie indicate a fairly stable situation on farmland plots but a progressive increase on woodland plots, with overall changes for the period 1966-1980 of +17% and +163% respectively (Marchant and Taylor 1981). Given the potential for colonising a new habitat, how can we account for the Magpie's success in the urban environment?…”