The moult of British Blue Tit and Great Tit populations

The effects of methods on estimates of primary moult duration in the RedshankTringa totanus

“…Branson and Minton (1976) calculated median dates for moult scores between 0 and 35 at five-point intervals. If the dates are normally distributed about each moult score then the median will be the same as the mean date, the method used by Snow (1969), Flegg and Cox (1969) and Francis (1980) (similar to Method F, Figure 3). Method G (Figure 4) gives similar results but the curve is now a much better fit to the data (Table III).…”

Post‐juvenile moult in relation to dispersal and migration in the ChiffchaffPhylloscopus coltybita

“…In many species replacement of some natal feathers in the alar (wing) and caudal (tail) tracts also takes place during post-juvenile moult, however there is considerable variation in the extent of moult within and between species (Snow 1967, Flegg & Cox 1969, Baillie & Swann 1980. There are also annual and geographical variations (O'Connor 1984) This paper examines the timing, sequence, extent and duration of post-juvenile moult in the Chiffchaff in relation to dispersal and migration.…”

Moult and its Relation to Eruptive Activity in the Bearded Reedling

“…Eruption and most of the consequent movement into distant wintering areas are completed between September and November, with the result that only a few weeks are available for moult. It is not surprising, therefore, that the duration of moult in the adult Bearded Reedling, about 45-50 days, is considerably less than the 115-120 days required by the Great Tit Parus major and the Blue Tit P. caeruleus (Flegg and Cox 1969). The Bearded Reedling is one of a very small group of British passerines in which post-juvenile moult is complete (Snow 1967).…”

“…If the date of onset does not vary too widely, such cases may be dealt with by regression analysis (see Evans 1966). Where moult score does not increase linearly, as for example in the Blue Tit Parus caeruleus (Flegg and Cox 1969), other methods of analysis must be used. Such cases may often be dealt with by calculating and plotting mean dates for various groups of moult scores (Snow 1969), a technique which has the advantage of minimising any trapping bias for or against a particular moult stage.…”

“…Recent determinations of the speed and timing of moult in British passerine species (Newton 1967, Snow 1969, Evans 1966, Flegg and Cox 1969, Bell 1970 have relied mainly on analysis of scatter diagrams of moult score plotted against date. For finches and thrushes, progress proceeds more or less linearly with time, and the scatter diagrams approximate to parallelograms.…”