Further studies on the breeding biology of redshank (Tringa totanus L.)
Redshank breeding biology is examined and reviewed in relation to other sandpiper studies. "Primarily, general aspects are described. The mean clutch size was 3.82 eggs. Fourth eggs laid were significantly smaller and more likely to hatch last. Nest hatching success varied annually from 30-741, with tidal flooding the main cause of nest failure. In successful nests, hatch success was less variable. Chick size at hatch was positively correlated with egg size. Pre-fledging mortality is discussed in relation to overall fledging success. Surviving adults generally remained mate faithful. Experienced birds were found to nest earlier in the season and to produce larger eggs. In all years, female age correlated positively with egg volume. Inexperienced birds laid smaller eggs later in the season. Older birds were more successful at hatching eggs. Experienced breeders were more likely to return to their former breeding grounds than were younger birds, particularly when they were successful the previous year. Birds unsuccessful in the previous year were more likely to divorce. Divorced females were less site faithful than males and were more likely to disperse. Natal philopatry is discussed in relation to pre and postfledging mortality. Philopatry is non sex biased and is estimated at being very high. Chick growth and development is considered and an age determining formula devised for ageing chicks from their weight and bill length. Growth rates were constant between and within years. Annual adult survival (0.75), life expectancy (3.48 years), and study area population are calculated. An estimated 175 pairs breed in the restricted area (168 pairs/km ) and approximately 500 pairs on the Nature Reserve. A model of population dynamics estimates pre-fledging mortality at between 66-74%. Timing of breeding in other waders and a comparison with the related Greenshank are reviewed in the Appendices.