On the Breeding Ecology of Whinchats Saxicola rubetra in the Last Dutch Populations

We studied the breeding ecology of Whinchats Saxicola rubetra in four tiny (less than 10 breeding pairs) populations in nature reserves in the Dutch province of Drenthe. We focussed on reproductive rates (laying date, clutch size, hatchling number, breeding success), proportion of unpaired males and nestling diet. Breeding pairs appeared to cluster together, thereby leaving other seemingly suitable parts of the area unoccupied. Clutch size, nest and pair success were similar to or higher than those in other studies. Laying of first eggs peaked during 16–20 May and laying dates had not advanced since the 1950s, in contrast to many other songbirds. We found 34% of the males remained unpaired, limiting the population reproduction rate. Whinchats provided their nestlings primarily with beetles and caterpillars and feeding frequency appeared to depend on prey species. Higher feeding frequencies may lead to a higher risk of nest predation. Being single-brooded, Whinchat populations may be more affected by nest predation than populations of multi-brooded species.