Kraanvogels Grus grus in het Fochteloërveen

The Fochtelogrveen is a peat moor relic of 2000 ha at the border of the provinces of Frisia and Drenthe in the northern part of The Netherlands. From 1999 onwards cranes, between which two pairs, regularly visited the area. In 2000-02 they only were absent during spells of cold weather (Table 1). In 2001 one of the pairs produced one egg and successfully raised a chick. In 2002 both pairs started a breeding attempt, but one failed in an early stage. The other pair laid one egg and raised the chick. Clutches of one egg are rare in Common Cranes and probably the breeding birds on the Fochtelogrveen are young and/or inexperienced. The Cranes used a large part of the Fochtelogrveen and its surroundings to forage (Figure 1). Earlier and later in the season they mainly foraged on the adjacent agricultural fields, especially on harvested maize, cereals and potatoes. The night was spent in shallow water on the peat moor. The nests were built in very wet parts of the peat moor, far away from human disturbance. During the first days the pairs and young foraged close to the nest in an area of no more than 1.5 ha. In 2001 from day 12 to day 50 the parents with the young occupied an area of c. 30 ha on the peat moor to forage and sleep. During the first days after hatching the chicks were fed with invisible prey items, probably insects. Later on the parents offered it pupae or larvae (2) dragonflies (2), lizards (4) snakes (2), frogs (4) mushrooms (7) and lots of berries of Vaccinium corymbosum. The choice of the Fochtelogrveen as the first breeding site in the Netherlands is not coincidental. Compared to other areas the Fochteloerveen and surroundings are extreme thinly populated, the wet nature reserve is not bordered by roads, so the birds have freely access to the bordering agricultural fields and the whole area is hard to penetrate because of lack of roads and because of a prison complex in the forests north of the peat moor.