Fallow deer

The Rhodian population of fallow deer are smaller on average than those of central and northern Europe, though they are similarly coloured. In 2005, the Rhodian fallow deer was found to be genetically distinct from all other populations and to be of urgent conservation concern.[12] At the entrance to the harbour of Rhodes city, statues of a fallow deer buck and doe now grace the location where the Colossus of Rhodes once stood.

Outside of Europe, this species has been introduced to Antigua and Barbuda, Argentina, South Africa, Fernando Pó, São Tomé, Madagascar, Mauritius, Mayotte, Réunion, the Seychelles, the Comoros, Morocco, Algeria, Tunisia, Cyprus, Israel, Cape Verde, Lebanon, Australia, New Zealand, Canada, the United States, the Falkland Islands, and Peru.[13]

Fallow deer were introduced to Tasmania in 1830 and to mainland Australia in the 1880s. The deer can now be found in all Australian jurisdictions, except Western Australia and the Northern Territory. The Fallow deer is the most widespread and numerous of introduced deer species in Australia.[14] Proper control of deer in New South Wales was precluded for some years, by the classification of these deer as 'game animals' as well as being a feral pest species.[15] This led to an explosion in numbers, a vast increase in range in that state, impacts on agricultural production, increased environmental damage, and a dramatic increase in vehicle accidents involving deer.[16] This policy has since been reversed on privately held land only, and on such land the deer is once again only classified as a feral pest species; they remain 'game animals' on public land. The N.S.W. Government now asks the public to assist by "not transporting or releasing feral deer onto any land", implying that intentional release of deer has been a factor in the vast increase in range, in New South Wales, in recent years.[17][18]

The fallow deer was introduced to Victoria Island in Neuquén Province by billionaire Aaron Anchorena, who intended to increase hunting opportunities. He freed wildlife of European and Asian origin, making them common inhabitants of the island.

The fallow deer was spread across central Europe by the Romans. The Normans are thought to have first introduced them to Great Britain from Sicily for hunting in the royal forests. However, recent finds at Fishbourne Roman Palace show that fallow deer were introduced into southern England in the 1st century AD.[19] Whether these escaped to form a feral colony, or whether they died out and were reintroduced by the Normans is unknown.

Fallow deer are now widespread on the U.K. mainland and are present in most of England and Wales below a line drawn from the Wash to the Mersey. Populations in the New Forest and the Forest of Dean are long-standing, and many of the other populations originated from park escapees. They are not quite so widespread in the northern parts of England, but are present in most lowland areas and also in parts of Scotland, principally in Strathtay and around Loch Lomond. According to the British Deer Society distribution survey 2007, they have increased in range since the previous survey in 2000, although the increase in range is not as spectacular as for some of the other deer species.

A significant number of the fallow deer in the Forest of Dean and in Epping Forest are of the black variety. One particularly interesting population, known as "long-haired fallow deer", inhabit Mortimer Forest on the England/Wales border; a significant part of the population has long body hair with distinct ear tufts.[20]

A historical herd is at Phoenix Park in Ireland where a herd of 400–450 fallow deer descends from the original herd introduced in the 1660s.[21]

Three of the fallow deer colour variants found at the Fossil Rim Wildlife Center in Texas

From 1860, fallow deer were introduced into New Zealand. Significant herds exist in a number of low-altitude forests.[22]

Fallow deer are popular in the rural areas of KwaZulu-Natal for hunting purposes, in parts of the Gauteng province to beautify ranches, and in the Eastern Cape where they were introduced on game farms for the hunting industry because of their exotic qualities. Fallow deer adapted extremely well to the South African environment with access to savanna grasslands and particularly in the cooler climate ranges such as the highveld.

One noted historical herd of fallow deer is located in the Ottenby nature reserve in Öland, where Charles X Gustav of Sweden erected a dry stone wall some 4 km long to enclose a royal fallow deer herd in the mid-17th century; the herd still exists as of 2006.[23]

In recent times, fallow deer have been introduced in parts of the United States. A small feral population exists on one barrier island in Georgia.[24] Fallow deer have also been introduced in Texas, along with many other exotic deer species, where they are often hunted on large game ranches.

In Pennsylvania, fallow deer are considered livestock, since no feral animals are breeding in the wild. Occasional reports of wild fallow deer in Pennsylvania and Indiana are generally attributed to escapes from preserves or farms.

A herd of white fallow deer is located near Argonne National Laboratories in northeastern Illinois.[25]

White fallow deer near Argonne National Labs in Westmont, Illinois, U.S.

A small herd of 15 mostly white fallow deer resides at the Belle Isle Nature Zoo on Belle Isle in Detroit, Michigan. Until the turn of the 21st century, this herd had the run of the island; the herd was thereafter confined, with extirpation being the initial goal.

A small herd, believed to be the oldest in the United States, exists in the Land Between the Lakes National Recreation Area (LBL) in far western Kentucky and Tennessee. The fallow deer herd in the LBL "was brought to LBL by the Hillman Land Company in 1918. LBL's herd is believed to be the oldest population of fallow deer in the country, and at one time was the largest. Today, the herd numbers fewer than 150 and hunting of fallow deer is not permitted. Although LBL's wildlife management activities focus on native species, the fallow herd is maintained for wildlife viewing and because of its historical significance."[26]

Fallow deer are present in the Point Reyes National Seashore, California; some of them are white.

Fallow deer herd

Many deer species—including fallow deer—have a social organization which can be tremendously plastic depending on their environment, meaning that group size and habitat type are closely linked to herd size.[32] It is important to note that most of the detailed research on the ecological characteristics and behaviour of fallow deer occur in large blocks of woodland, which means there may be some bias present.[32] Fallow deer can be found in a variety of habitats, which can range from cool and wet to hot and dry.[27] Fallow deer seem to have a preference for older forests with dispersed areas of grass, trees, and a variety of other vegetation.[27] The largest herd occurs right before the rutting season, while the smallest groups are females with fawns.[27] Throughout a large portion of the year the sexes remain separated and only congregate during the mating months; however, other patterns may be described, such as bachelor groups and even mixed groups.[32]

In male fallow deer, their low frequency groans are produced by vocal tracts that are of consistent but complex shape. Experimentation showed that vocal production of these groans are dependent on both their nasal and oral cavities.[33]

Ruts are characterized by males gaining the best territory possible to increase their odds for mating and are often characterized by the presence of females on stands.[27] During this time, males will stop feeding to defend their ruts from subordinate males. Males defending this territory will often lose an average of 17% of their body weight, and the liver will exhibit steatosis, which is reversible.[27] Throughout breeding seasons, the male may obtain the same rut; in some cases, ruts can be held by more than one individual; some possibilities for this include high population density and less rut space, or more suitable habitats which can be shared.[32]

Mother fallow deer and fawn

After the females are impregnated, the gestation period lasts up to 245 days and usually one fawn is born, as twins can be quite rare.[27] The females can conceive when they are 16 months old, whereas the males can successfully breed at 16 months, but most do not breed until they are 48 months old.[27] The females can become very cagey just before they give birth to their fawn and find secluded areas such as a bush or cave; sometimes females will give birth near the herd.[27] As soon as the female gives birth, the female will then lick the fawn to clean it; this helps initiate the maternal bond between the two, females are the only sex that provides parental investment; males do not participate in rearing the fawn.[27][29]

After the birth of the fawn occurs, the females do not return to the herd for at least 10 days and for most of the days the mother is separated from the fawn, returning only to feed the fawn.[27] The nursing period lasts about 4 months and happens every 4 hours each day.[27] Rumination is a critical part of development in the fawn's life, and this develops about 2 to 3 weeks into the fawn's life.[27] Females initiate the weaning periods for the fawn which lasts about 20 days; 3 to 4 weeks; later, the fawn will start to follow its mother, and they will finally rejoin the herd together.[27] The mother frequently licks the fawn's anal area to stimulate suckling, urination, and defecation, which is a critical part of the development of the fawn.[27] Weaning is completed at around 7 months and at around 12 months the fawn is independent; after the 135 days of reproduction, the rut comes to an end, which can be characterized by the changes in group size and behaviour.[27]

Fallow deer bucks fighting at Charlecote Park

Since fallow deer are polygynous species that congregate once every year, males must fight to obtain access to estrous females.[34][29] The relationship between antler size and body condition can be treated as indicators to reflect body condition within a given year.[35] These secondary sexual characteristics can have dual functions, which include the attractiveness of males which females can ultimately choose and fighting ability of the male.[36][37][38][34] It was found that males with larger antlers had higher mating success, where males with asymmetrical antlers did not.[35] When males develop their antlers, there are always trade-offs between reproduction and survival, which can shape the decision in an individual's choice.[34] Genetic variations exist within fallow deer populations with variable antler growth, males that exhibited faster-growing antlers early in life are able to grow longer antlers without any significant cost; this shows that there is, in fact, phenotypic variation among fallow deer populations.[34]

Aggressive behaviour is often observed when individuals are seeking out mates, scarce resources, and even territories.[39] Species that compete using their weapons usually engage when there is a mutual agreement, but if there are any noticeable asymmetries such as a broken or lost weapon this may alter the behaviour of an individual to engage in a fight.[39] Likelihood and severity of antler damage were looked at in fallow deer, to test whether antler damage was associated with contest tactics and duration, and if there was an association with the tendency for individuals to engage in fighting.[39] Individuals with undamaged antlers were more likely to attack, using high-risk tactics which included jumping, clashing, or backward-pushing behaviour, this was exhibited by both contestants; dominant males were more likely to have damaged antlers.[39] Dominance ranks exist within fallow deer populations, which can be linked to aggression level and body size; when competing for a male, however, how ranks are obtained is not studied extensively.[40]

Male fallow deer

Male fallow deer are highly competitive during the rutting season; successful mating depends mainly on body size and dominance rank.[41] Many factors can determine the seasonal reproductive success of an individual male fallow deer; these factors include body size, which can affect reproduction and survival.[41] The amount of time spent in a lek can be an important factor in determining male reproductive success; energy can play an important role for the duration of competitive leks.[42] Among ungulates, fallow deer exhibit one of the most outstanding examples of sexual dimorphism, as males are much larger than females.[41] For sexual selection to lead to the evolution of sexual dimorphism, where males are bigger than females, there must be advantages: (1) advantages during combat, (2) endurance rivalry advantage, (3) female preference for larger males and (4) advantages during sperm competition.[38][41] Sexual selection has chosen bigger males over an evolutionary time scale and conferred advantages during competition of mates by a variety of mechanisms, which are intrasexual competition, access to females, and resource accessibility, which effects female attractiveness.[41]

Body size is important during male-male agonistic interactions and endurance rivalry, while females tend to have a preference for larger males.[43] Dominance rank is a good indicator of body size and body mass, however, age was not an important factor.[41] In a study done by McElligott et al. (2001), it was found that mating success was related to body size, pre-rut and rut rank.[41] Similarly, in another study, researchers found that age, weight, and display effort were all significant factors in determining mating success; in both studies, mating success was measured by the frequency of copulations,[43][41] 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.[41] 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.[41]

Fallow deer fawn in Uruguay