THE ROOSTING OF JACKDAWS IN MERTHYR TYDFIL JOHN GRIFFITHS and Gwilym GRIFFITHS From 1952 to 1956, and intermittently in later years, we noted the daily movements of local Jackdaws (Corvus monedula) to and from their roost in the Taff valley, Glamorgan. After only a few months of close observation several facts became apparent. The first of these was that the times of the evening flight to the roost obviously followed a very definite pattern, and from timings made over the 3-4 year period we were eventually able to plot a graph (Fig. 1) showing how the normal flight-times varied throughout the year. On this graph each dot indicates the beginning of a month and not a specific observation. The second fact was that, as mentioned above, the Jackdaws roosted throughout the year, and not just during the non-breeding season. A short note to this effect appeared in British Birds, 48, 139, and other observers, such as Brownsey and Peakall (1955) and Burns (1957), describe how Jackdaws in Surrey and Hertfordshire, respectively, also roost throughout the summer, but in each case at a different roost from that used in winter. In the early 1950s the Merthyr valley Jackdaws used the same local roost, some 1-3 miles Fig 1. Evening flight of Jackdaws to roost in Merthyr Valley, Glamorgan, mid-1950s.