MAJOOR F, HORSSEN P VAN & DIJK K VAN (2005) Survival of Black-headed Gulls Larus ridibundus wintering in urban areas in the Netherlands. LIMOSA 78 (3): 85-96.

This paper presents an estimate of the annual survival of Black-headed Gulls wintering in urban parks in The Netherlands. These Blackheaded Gulls breed in a large area around the Baltic Sea (Fig. 1) and are often very tame, which enabled us to read the inscription of metal rings and colour-rings using binoculars or a telescope. Systematic observations of birds with metal rings carried out in Hilversum (52.13N, 05.11E) in November-February between 1985/86 and 2002/03 yielded a total of 935 individuals that were observed at least once (Table 1). Besides, a total of 1453 wintering gulls (712 first-winter; 741 adults) was colour- ringed in eight cities in the central and northern parts of The Netherlands from late 1996 to late 2002. Of these, 1121 individuals (77.2%) were observed at least once over the winters 1996/97 to 2002/03.
      We used capture-recapture analyses performed with the MARK software to estimate apparent survival rates and calculated separate estimates for the first year after capture or first observation and for later years ('transient' model of Pradel et al. 1987, Prévot-Julliard et al. 1998). Resident gulls in Hilversum survived at a mean annual rate of 0.80 (SE=0.07) after the first year after first observation, with no obvious trend in the time (Fig. 2). Resident colour-ringed gulls (Table 2) survived at a mean annual rate of 0.83 (SE=0.01). Compared to resident birds, the apparent survival during the first year after capture or first observation was much lower, caused by the presence of transients. We did not find a significant relation between survival and the severity of the winter (Fig. 3).
      Average annual survival rates of resident gulls in this study are higher compared to most estimates from earlier studies that analysed recoveries of dead birds. However, most survival rates reported in such studies are biased and less reliable because analyses of individuals ringed as chicks and later found dead carry several assumptions that are rarely true. Survival rates of resident birds in our study were somewhat lower than survival rates calculated from capture-recapture analyses of breeding birds in France, but our analysis shows no evidence that the decrease in the population size in western and northern Europe is driven by a low survival rate of adult birds. Black-headed Gull Chroicocephalus ridibundus = Larus ridibundus

[free pdf] [dutch summary]