Ardea
Official journal of the Netherlands Ornithologists' Union

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Foppen R.P.B., Majoor F.A., Willems F.J., Meininger P.L., van Houwelingen G.Ch. & Wolf P.A. (2006) Survival and emigration rates in Kentish Charadrius alexandrinus and Ringed Plovers Ch. hiaticula in the Delta area, SW-Netherlands. ARDEA 94 (2): 159-173
Ringed Plover Charadrius hiaticula and Kentish Plover Charadrius alexandrinus are typical species of the Delta area, southwest Netherlands. A major part of the Dutch population of both species occurs in this area. Between 1999 and 2002 the breeding populations in the Dutch Delta were studied. One of the aims of the study was to estimate survival, emigration and dispersal rates and to explain variation therein. To estimate annual apparent survival rates we used mark-recapture analyses (program MARK) of the resighting histories of colour ringed individuals. The best survival model of Ringed Plover showed an age (first years against adults) and year effect. Apparent survival in the last year of study was much lower than in previous years. Also juvenile survival of Kentish Plover was considerably (40%) lower than adult survival. Furthermore, two year old females had a lower survival rate than older females. In the first year after marking the apparent survival of females was 40% lower than in later years. Kentish Plovers that were unsuccessful in breeding were more prone to disperse the year after. Generally, breeding dispersal in both species was restricted to short distances (median <2 km), although occasionally Kentish Plovers dispersed over larger distances. Natal dispersal distances were larger (median 1015 km), although few individuals dispersed outside the Delta region. We distinguished various geographical subpopulations, and recorded emigration rates between these subpopulations. An extended survival model with emigration events provided estimates for emigration rates in relation to distance between sites. We used emigration and apparent survival rates to estimate true survival rates. We compared estimates with literature data and discussed possible explanations for effects of age and time since marking on survival rates. Particularly relevant were the large-distance dispersal events following breeding failure and/or mate change during the breeding season.


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