A contemporary observer, naturalist Joseph Grinnell, noted in that "This [roadkill] is a relatively new source of fatality; and if one were to estimate the entire mileage of such roads in the state [California], the mortality must mount into the hundreds and perhaps thousands every 24 hours.
In Europe and North America , deer are the animal most likely to cause vehicle damage. In Australia , specific actions taken to protect against the variety of animals that can damage vehicles — such as bullbars usually known in Australia as 'roo bars', in reference to kangaroos — indicate the Australian experience has some unique features with road kill. The development of roads affects wildlife by altering and isolating habitat and populations, deterring the movement of wildlife, and resulting in extensive wildlife mortality.
A study in Ontario , Canada in found many reptile killed on portions of the road where vehicle tires do not usually pass over, which led to the inference that some drivers intentionally run over reptiles. On roadways where rumble strips are installed to provide a tactile vibration alerting drivers when drifting from their lane, the rumble strips may accumulate road salt in regions where it is used.
The excess salt can accumulate and attract both small and large wildlife in search of salt licks ; these animals are at great risk of becoming roadkill or causing accidents. Very large numbers of mammals, birds, reptiles, amphibians and invertebrates are killed on the world's roads every day.
About , to 27 million birds are estimated to be killed on European roads each year. Mortality resulting from roadkill can be very significant for species with small populations. Roadkill is considered to significantly contribute to the population decline of many threatened species, including wolf , koala and eastern quoll.
In , 25 schools throughout New England , United States participated in a roadkill study involving 1, animal deaths. A recent study showed that insects, too, are prone to a very high risk of roadkill incidence. In , the Royal Society for the Protection of Birds investigated anecdotal reports of declining insect populations in the UK by asking drivers to affix a postcard-sized PVC rectangle, called a "splatometer", to the front of their cars. This contrasts with 30 years ago when cars were covered more completely with insects, supporting the idea that insect numbers had waned.
In , Dutch biologist Arnold van Vliet coordinated a similar study of insect deaths on car license plates. He found two insects killed on the license-plate area for every 10 kilometres 6. This implies about 1. One rarely considered positive aspect of roadkill is the regular availability of carrion it provides for scavenger species such as vultures , crows , foxes , Virginia opossums and a wide variety of carnivorous insects. Areas with robust scavenger populations tend to see roadkilled animal corpses being quickly carried off, sometimes within minutes of being struck. This can skew data and cause a lower estimation of the number of roadkill animals per year.
However, such scavengers are at greater risk of becoming roadkill themselves, and are subject to evolutionary pressure to be alert to traffic hazards. In contrast, areas where scavengers have been driven out such as many urban areas often see roadkill rotting in place indefinitely on the roadways and being further macerated by traffic. The remains must be manually removed by dedicated disposal personnel and disposed of via sanitary cremation ; this greatly increases the public nuisance inherent to roadkill, unnecessarily complicates its disposal, and consumes additional public money, time and fuel that could be spent on other roadway maintenance projects.
The study of roadkill has proven highly amenable to the application of citizen science observation methods. Since , statewide roadkill observation systems have been started in the US, enrolling hundreds of observers in reporting roadkill on a website. The observers, who are usually naturalists or professional scientists, provide identification, location, and other information about the observations. The data are then displayed on a website for easy visualization and made available for studies of proximate causes of roadkill, actual wildlife distributions, wildlife movement, and other studies.
Roadkill observation system websites are available for the US states of California,  Maine,  and Idaho. Mohammed Saleem, had undertaken a forty-four-day expedition, traveling more than 17, kilometers across 22 states to study and spread awareness on roadkill. In the Czech Republic, an online animal-vehicle crash reporting system Srazenazver.
Regardless of the spatial scale at which the mitigation measure is applied, there are two main types of roadkill mitigation measures: changing driver behavior, and changing wildlife behavior. There are three potential ways to change driver behavior.
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Primary methods focus on changing driver attitude by increasing public awareness and helping people understand that reducing roadkill will benefit their community. The second potential way is to make people aware of specific hazardous areas by use of signage, rumble strips or lighting. The third potential way is to slow traffic physically or psychologically, using chicanes or speed bumps.
There are three categories of altering wildlife behavior. Primary methods discourage wildlife from loitering on roadsides by reducing food and water resources, or by making the road surfaces lighter in color which may make wildlife feel more exposed on the roadway. Second are methods of discouraging wildlife from crossing roads, at least when cars are present, using equipment such as ultrasonic whistles, reflectors, and fencing.
Third are mechanisms to provide safe crossing like overpass , underpasses and escape routes. In the US, an estimated 1. Collisions with large animals with antlers such as deer are particularly dangerous, but any large, long-legged animal e. Dusk and dawn are times of highest collision risk. The recommended reaction to a large animal such as a moose is to slow down in lane, if at all possible, and to avoid swerving suddenly, which could cause loss of control.
Acoustic warning deer horns can be mounted on vehicles to warn deer of approaching automobiles, though their effectiveness is disputed. Squirrels , rabbits , birds , or other small animals are often crushed by vehicles. Serious accidents may result from motorists swerving or stopping for squirrels in the road.
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There is very little a driver can do to avoid an unpredictably darting squirrel or rabbit, or even to intentionally hit one. The suggested course of action is to continue driving in a predictable, safe manner, and let the small animal decide on the spur of the moment which way to run or fly; the majority of vehicular encounters end with no harm to either party.
Although strikes can happen at any time of day, deer tend to move at dusk and dawn, and are particularly active during the October—December mating season as well as late March and early April in the Northern Hemisphere. Penguins , for example, are common roadkill traffic victims in Wellington, New Zealand , due to their skin color and the fact that they come ashore at dusk and leave again around dawn. Night time drivers should reduce speed and use high beam headlights when possible to give themselves maximum time to avoid a collision.
Furthermore, the glare of oncoming vehicle headlights can dazzle some species, such as rabbits; they will freeze in the road rather than flee.
It may be better to flash the headlights on and off, rather than leaving them on continuously while approaching an animal. Wildlife crossings allow animals to travel over or underneath roads. They are most widely used in Europe, but have also been installed in a few US locations and in parts of Western Canada. As new highways cause habitats to become increasingly fragmented, these crossings can play an important role in protecting endangered species. In the US, sections of road known to have heavy deer cross-traffic will usually have warning signs depicting a bounding deer; similar signs exist for moose, elk, and other species.
In the American West , roads may pass through large areas designated as " open range ", meaning no fences separate drivers from large animals such as cattle or bison. A driver may round a bend to find a small herd standing in the road.
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Open range areas are generally marked with signage and protected by a cattle guard. The sensor's detection distance ranges from feet to unlimited, depending on the terrain. The removal of trees associated with road construction produces a gap in the forest canopy that forces arboreal tree dwelling species to come to the ground to travel across the gap. Canopy crossings have been constructed for red squirrels in Great Britain, colobus monkeys in Kenya, and ringtail possums in Far North Queensland, Australia. Installation of the canopy crossings may be relatively quick and cheap.
Banks, cuttings and fences that trap animals on the road are associated with roadkill.
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Escape routes may be considered as one of the most useful measures, especially when new roads are being built or roads are being upgraded, widened or sealed. In the New Forest , in southern England , there is a proposal to fence roads to protect the New Forest pony. Removing animal carcasses from roadways is considered essential to public safety. Local governments and other levels of government have services that pick up dead animals from roadways, who will respond when advised about a dead animal.
New York City has an online request form which may be completed by residents of the city. In Toronto , Canada, the city accepts requests to remove a dead animal by telephone. Roadkill can be eaten, and there are several recipe books dedicated to roadkill. The practice of eating animals killed on the road is usually derided, and most people consider it not to be safe,  sanitary, or wholesome.
For example, when the Tennessee legislature attempted to legalize the use of accidentally killed animals, they became the subject of stereotyping and derisive humor.
The song describes an encounter with a roadkilled opossum and includes the lyric, "Your end is the road. Roadkill is sometimes used as an art form. Several artists use traditional taxidermy preparation in their works whilst others explore different artforms. International artist Claudia Terstappen photographs roadkill  and produces enormous prints which see the animals floating eerily in a void.
Canadian writer Timothy Findley wrote about the experience of seeing killed animals on highways during travels: "The dead by the road, or on it, testify to the presence of man. Their little gestures of pain—paws, wings and tails—are the saddest, the loneliest, most forlorn postures of the dead I can imagine. If the animal is near a field or wooded area, staff does their best to move the animal out of view from the road and allow nature to take its course.
Whenever possible, wardens attempt to collect the animal and donate it to people who will salvage it and make use of the meat.
However, there are some places, such as the medians of busy interstate highways, where it is not safe or practical for staff to access a carcass, and which may result in the carcass remaining in plain view of drivers until it decomposes naturally. When safe to access the carcass and where dragging it into cover is not an option, it may be physically relocated to an area suitable for disposal outside the State owned right-of-way.
The two departments continue to work to improve wildlife crossing areas and to warn drivers of high-incidence stretches in order to make Vermont safe for wildlife and for drivers. Please stay alert while traveling Vermont's roadways and feel free to reach out to us for additional information. You can report observed roadkills by contacting your Vermont State Police local barracks. Staff Directory. Menu Vermont Official State Website.