THE BREEDING STATUS OF THE MERLIN FALCO-COLUMBARIUS IN BRITAIN IN 1993-94

Earlier this century there were widespread reports, but little detail, of declining Merlin populations in Britain. A partial survey in 1983- 84 resulted in an estimate of 550-650 breeding pairs. Local studies ha ve since reported increases, decreases and stability in Merlin populat ions. Against this background the RSPB organized the second breeding s urvey of Merlins in Britain during 1993 and 1994, to estimate the popu lation and assess regional trends. This survey located 796 breeding pa irs of Merlins and estimated a further minimum of 24 pairs from areas previously well surveyed, 53% of the known breeding range. For the rem ainder of the range all extrapolated estimate of 471 pairs with 95% co nfidence limits of 288-680 pairs was calculated following survey of 36 10-km National Grid squares. A number of checks were made on survey e fficiency and accuracy. It is recommended that a rounded figure of 130 0 +/- 200 pairs of breeding Merlins be used Its the revised population estimate for Britain. In all areas where comparisons were made betwee n surveys, Merlins have increased or remained stable. Reasons or this are discussed, as is the logic behind the species being retained in th e revised UK Red Data Bird list.