success was measured by the frequency of copulations, which means that a variety of factors in different fallow deer populations can affect the overall energy allocation which will ultimately affect mating success. Maternal investment early in life can be critical to the development of body size, since it can be quite variable at that stage depending on resources and habitat type. Mature male body size can be a better indicator of overall male quality rather than body mass, since body mass depends on a variety of resources each year and is not a static trait; body mass can be a complex trait to measure. Threats Since the 20th century, a serious decline in the populations of European fallow deer has been seen in Turkey, the only region where it is definitely thought to be native, and it has disappeared from almost all regions where it was formerly found aside from Düzlerçami Game Reserve in the Mount Güllük-Termessos National Park, where a semiwild, genetically distinct population exists. The Turkish government undertook a breeding program at Düzlerçami starting in 1966, with the population growing from 7 to 500 animals, but it underwent a massive collapse until 2000 due to reasons not fully understood, but thought to be linked to urbanisation, recreational activities, and poaching, and numbered less than 30 (with only 10 individuals roaming outside the fenced areas) individuals by 2007 and less than 130 individuals by 2010. This population remains at risk from inbreeding and poaching. Reintroduction to other areas of Turkey has not been successful but should still be considered to increase the species' population. The population on Rhodes, which is of uncertain origin, but is known to be very genetically distinct from others, is also of major conservation concern. It numbers around 400-500 animals and is at risk from poaching and wildfires. The population is also at risk of outbreeding depression, as in some parts of Rhodes, mainland European fallow deer are kept in fenced areas; these deer could escape and breed with the Rhodian fallow deer. Rhodian fallow deer also damage summer crops and due to a lack of a compensation system, persecution against the population could happen. A reduction of water resources on the island due to climate change could also affect the animals. Despite this, there are signs of population recovery on Rhodes as of 2008 due to conservation measures. Despite these threats, the European fallow