Winter reproduction of Eliomys quercinus (Rodentia) in the orange groves of Sagunto (Valencia, Spain) / La reproduction en hiver d' Eliomys quercinus (Rodentia) dans les orangeraies de Sagunto (Valence, Espagne)

Abstract

AbstractThe colonisation of orange groves in Eastern Spain by the garden dormouse Eliomys quercinus and their reproduction were studied. Litter sizes and times of birth of garden dormice were studied during the winter of 2003/2004 until the month of May 2004. The main study area was a plot covered by orange trees that has been monitored since 1975. Litters in nest boxes placed around the plot for birds, as well as a few litters in nests built in trees, were observed to obtain information on reproduction. The nests found in trees include some built in old bird nests, most of them belonging to the blackbird Turdus merula . We weighed the cubs to determine their month of birth and identified the population trend by counting the number of nests occupied simultaneously. Results show that there are births during the winter, that the number of cubs per nest ranged from 4 to 13, but 6 cubs was the mode. A total of 34 litters were found, with an average size of 5.76 cubs per litter. The litter of 13 cubs was excluded from analysis. Colonisation was suspected after a first specimen was observed in 1997 in the surroundings of the study area. Occupation by garden dormice of both natural nests and nest boxes subsequently increased from 1 to 27 between 1999 and 2004. We suggest that mild winter temperatures allowed the population increase and winter reproduction.