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Nov
10

Dispelling Myths about the Coyote in Florida, Or, Probably More Than You Wanted to Know about the Coyote in Florida

If you live in Florida you’ve probably heard people talk about coyotes (Canis latrans) in Florida.  Below are facts gleaned from the literature regarding this interesting mammal.

How Did the Coyote Get Its Name?

The accepted common name ‘coyote’ comes from the Aztec term for the species, Coyotl.  Other names used for this species in North America include coyóte (Mexican), brush-wolf, prairie-wolf, American jackal, and little wolf (Beebe 1964).

Why Did Coyotes Expand Their Range into the Eastern United States and Florida?

Most of us know that coyotes are not native to the eastern U.S., including Florida.  Their range has historically been limited to the western U.S. (Layne 1997).  Humans eliminated gray wolves and red wolves from the eastern U.S. in the early- to mid-1900s, with the red wolf being last recorded in Florida at that time (Beebe 1964).  Wolves were apparently a major constraint on the range of the coyote, so their recent absence from parts of the U.S. allowed for the natural expansion of the coyote’s range.  Thus, the expansion of the coyote into Florida and elsewhere in the eastern U.S. is most likely due to humans extirpating the wolves in this area.  Humans may have helped the coyote become established in Florida through accidental release or escape and (or) intentional release (Layne 1997), such as for hunting. 

Here’s a timeline of the presence of the coyote in Florida:

  • Pre-historic: Coyote fossils found in Florida geology dating to the Pleistocene (2.6 million to 11,700 years ago) (Webb 1974)
  • European colonization: No evidence of the species in Florida (Layne 1997)
  • 1970s: Coyotes were already well established in northern Florida (Layne 1997)
  • Early 1980s: The species was distributed through the middle of the Florida peninsula, from Hamilton County to Polk County (Brady and Campell 1983)
  • 1982: First sighting in Highlands County in southern Florida (Layne 1997)
  • 1988: The coyote’s range extended south to Broward and Collier counties (Wooding and Hardisky 1990)
  • 1995: A survey of coyote tracks by R. McBride found they were widely distributed in Highlands and Polk counties (Layne 1997)
  • 1991: Coyotes killed or trapped in Charlotte and Desoto counties (Layne 1997)
  • 2007: Coyotes documented in every county in Florida, and populations in Florida continue to increase (McCown and Scheick 2007)

What Habitats Do Coyotes Use Most Often?

In Florida, coyotes frequent improved pastures, native prairies, and citrus groves according to a survey by R. McBride cited in Layne (1997).  Den sites are located along brushy slopes, areas of thick undergrowth of vegetation, inside hollow logs, within rocky ledges, and burrows made either by adult coyotes or by other mammals.  Tunnels leading to the den may be 5 to 25 feet long (1.5 to 7.5 meters).  The den chamber itself measures about 1 foot (0.3 meters) in width and is commonly located 3.3 feet (1 meter) below-ground.  Coyotes may undertake seasonal migrations between habitats in some areas of North America (Novak 1999).

What Is the Average Size of the Coyote’s Home Range?

A coyote can cover a distance of about 2.5 miles (4 km) in a night while searching for a meal.  They traveled an average distance of 19.3 miles (31 km) from the point of capture in a tagging study in Iowa, but one individual covered a whopping 200 miles (323 km) during that study (Novak 1999).  A coyote tagged in south-central Canada traveled a record distance of 338 miles (544 km) from the point of capture (Carbyn and Paquet 1986).  Home range sizes vary greatly, from 3 to 31 square miles (8 to 80 km2).  Males have larger home ranges than do females, and male ranges overlap one another considerably.  Females ranges are smaller and do not overlap with those of other females (Novak 1999).

What’s the Average Population Density for Coyotes?

Population densities are generally between 0.1 and 0.2 coyotes per square mile (0.2 to 0.4 individuals/km2), but can be as high as 1.2 individuals per square mile (2.0/km2) in areas having extremely favorable conditions (Knowlton 1972, Bekoff 1977).  A study of coywolves (hybrid of coyote x eastern gray wolf [Canis lupus lycaon]) living north of Boston, Massachusetts, found a very high population density in fall and winter, at 1.1 to 1.3 individuals per square mile (2.9 to 3.4 individuals/km2) and 0.8 individuals per square mile (2.0 individuals/km2), respectively (Way 2011).

When Are Coyotes Most Active?

Coyotes can be active at any time of day or night, but they are mainly nocturnal and crepuscular (Novak 1999) (crepuscular means active around dawn and dusk [insect-eating bats are another example of crepuscular mammals]).

Does a Coyote Sighting Mean They Are More Common in the Area Than in Other Areas?

Coyotes are found in every Florida county.  Their level of abundance cannot be measured merely by anecdotal sightings since coyotes try to blend in with their surroundings and not be seen.  Sightings of coyotes do not necessarily mean that they are more abundant where sighted.  Coyotes are wherever there is suitable habitat, regardless of whether or not they are seen.  A sighting only confirms that coyotes are present.

What Do Coyotes Eat?

Coyotes mainly eat small mammals.  Rabbits and rodents make up the bulk (90%) of their diet in most areas.  Larger animals such as deer are also commonly eaten, but mostly as scavenged carcasses, although sometimes after a chase in which several coyotes worked together to take down the animal.  Other food items include fishes (which they are capable of snatching from streams!), lizards, snakes, birds such as turkeys, insects, grasses, fruits (including watermelon, persimmon, and various wild berries), and seeds (Novak 1999, Coates et al. 2002).  A tracking study conducted in Tucson, Arizona, found that over a 33-day period during November 2005 through February 2006, a group of eight coyotes killed 19 domestic cats (Harris Environmental Group 2015).  This interesting study further strengthens the idea that domestic cats are much better off if kept entirely indoors.  The coyote is also capable of preying on small domestic dogs (McCown and Scheick 2007).  Livestock are occasionally taken but the impact on livestock numbers is minimal (Novak 1999).  In the western U.S., where coyotes share their range with American badgers, the two species have been documented to form hunting partnerships whereby the coyote uses its excellent sense of smell to locate burrowing rodents, and the badger uses its powerful legs and claws to dig out the prey, which they then share (Novak 1999).

How Often Do Coyotes Prey on Domestic Livestock Like Cattle?

It is true that coyotes can kill and consume livestock including calves, poultry, pigs, and goats (Coates et al. 2002).  However, coyotes are not a serious problem to livestock (with the possible exception of sheep [Coates et al. 2002]) in most parts of their range, and reports of livestock damage from this species appear to be driven by popular perception and emotional reactions.  In the words of the past Chief Game Biologist for Mississippi, H.E. Alexander, “Reports of livestock damage from these animals seems to be more dependent on popular attitudes and emotional reactions to conspicuous evidence of depredations at some time and place than on actual fluctuations [of coyote populations]” (Beebe 1964).  Coyotes are not a major concern to livestock producers in Florida according to McCown and Scheick (2007).

What’s the Average Size and Weight of an Adult Coyote?

Adult male coyotes weigh 18 to 44 pounds (8 to 20 kg).  Adult females weigh 15 to 40 pounds (7 to 18 kg).  Coyotes living in northern regions weigh more, on average, than do those living in southern regions of North America (Nowak 1999).  The average weight of a coyote in Alaska is 40 pounds (18 kg), contrasting with the average weight of 25 pounds (11.5 kg) for coyotes living in the deserts of Mexico according to Gier (1975).  An unusually heavy coyote from Canada that weighed 46 pounds (21 kg) was noted by Beebe (1964).  The largest coyotes are those living in the northeastern United States, owing to enhanced nutrition there and (or) hybridization with the gray wolf (Nowak 1999).  In general, coyotes are larger than foxes but smaller than wolves (Coates et al. 2002).

How Fast Can Coyotes Run?

Coyotes are very speedy runners!  Picture this: a coyote racing in the World Championships in Athletics against legendary world record-holder Usain Bolt.  Usain runs a breathtakingly fast time of 9.58 seconds for the 100‑meter sprint.  That’s 23.4 miles per hour (mph) (37.7 km/hour)!  Now, let’s focus on the coyote.  The coyote explodes out of the starting line at a staggering pace, crossing the finish line in about half the time (4.47 seconds) it took Usain to cover the same distance!  That’s right, coyotes are fast and capable of running at speeds of up to 50 mph (80.5 km/hour) (Sooter 1943, Fisher 1975).  Although Novak (1999) gives a top speed of 64 mph (103 km/hour), this is higher than what is stated by most other sources.  Coyotes are clearly one of the fastest terrestrial mammals in North America.

Coyote Reproduction 101

Litter size averages about 6 pups but ranges from 2 to 12 pups.  Large numbers of pups have been found in a single den but were probably the result of litters from more than one female.  Females produce only one litter annually (Novak 1999).  Mating occurs during January through March, and gestation takes about 2 months (Coates et al. 2002).  Parturition (birthing) takes place in spring.  The pups weigh only about 8.8 ounces (250 grams) at birth.  Their eyes don’t open until day 14.  Young emerge from the den within about 3 weeks of birth and are fully weaned at about 9 months, at about which time they approach the weight and size of adult coyotes.  The average life span is less than 6 years, with the most significant mortality being within the first year of life (Coates et al. 2002).  The maximum longevity was recorded at 14.5 years in the wild, but most wild coyotes do not survive this long.  One long-lived captive coyote lived 21 years and 10 months (Jones 1982).

Do Coyotes Sometimes Hybridize with Other Canids?

Coyotes are well known to interbreed with domestic dogs (producing what are called ‘coydogs’).  Coyotes also interbreed with eastern gray wolves (Way 2011) as well as with red wolves (Canis lupus rufus), producing ‘coywolves’.  The offspring produced are fertile. 

What Are the Regulations on Hunting Coyotes in Florida?

The hunting and trapping of coyotes is allowed year-round throughout Florida (http://myfwc.com/‌hunting/season-dates).  However, a permit from the Florida Fish and Wildlife Conservation Commission (FWC) is needed for using steel traps, such as leg-hold traps.  More information on how to apply for a steel trap permit is found at http://myfwc.com/license/wildlife/nuisance-wildlife/steel-traps/.  FWC keeps a list of nuisance-wildlife trappers at https://public.myfwc.com/HGM/NWT/NWTSearch.aspx?.

Sources

Beebe, B.F.  1964.  American Wolves, Coyotes, and Foxes.  David McKay Co., Inc., New York, NY.

Bekoff, M.  1977.  Social behavior and ecology of the African Canidae: A review.  Pp. 120–142.  In: M.W. Fox (ed.)  The Wild Canids: Their Systematics, Behavioral Ecology and Evolution.  R.E. Krieger Publishing Co., Inc., Malabar, FL.

Brady, J.R. and H.W. Campell.  1983.  Distribution of coyotes in Florida.  Florida Field Naturalist 11:40–41.

Carbyn, L.N. and P.C. Paquet.  1986.  Long distance movement of a coyote from Riding Mountain National Park.  Journal of Wildlife Management 50:89.

Coates, S.F., M.B. Main, J.J. Mullahey, J.M. Schaefer, G.W. Tanner, M.E. Sunquist, and M.D. Fanning.  2002.  The Coyote (Canis latrans): Florida’s Newest Predator [online resource].  Wildlife Ecology and Conservation Dept. document WEC124, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, UF, Gainesville, FL.  Accessed 04/22/15 at http://edis.ifas.ufl.edu/pdffiles/UW/UW12700.pdf.

Fisher, J.  1975.  The plains dog moves east.  National Wildlife 13(2):1417.

Gier, H.T.  1975.  Ecology and behavior of the coyote (Canis latrans).  Pp. 247–262.  In: M.W. Fox (ed.) The Wild Canids: Their Systematics, Behavioral Ecology, and Evolution.  Van Nostrand Reinhold, New York, NY.

Harris Environmental Group, Inc.  2015.  Coyote’s Eat Cats! [online resource].  Accessed 04/22/15 at http://www.heg-inc.com/2009/08/coyotes-eat-cats/.

Jones, M.L.  1982.  Longevity of captive mammals.  Der Zoologische Garten 52:113–128.

Knowlton, F.F.  1972.  Preliminary interpretations of coyote population mechanics with some management implications.  Journal of Wildlife Management 36:369–382.

Layne, J.  1997.  Nonindigenous mammals. Pp 157–186.  In: D. Simberloff, D.C. Schmitz, and T.C. Brown (eds.), Strangers in Paradise, Impact and Management of Nonindigenous Species in Florida.  Island Press, Washington, D.C.

MacCown, W. and B. Scheick.  2007.  The Coyote in Florida [online resource].  Florida Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Tallahassee, FL.  Accessed 04/22/15 at http://myfwc.com/media/1228800/CoyoteWhitePaperFinal.pdf.

Nowak, R.M.  1999.  Walker’s Mammals of the World, Sixth Edition, Volume I.  The Johns Hopkins University Press, Baltimore, MD.

Sooter, C.A.  1943.  Speed of a predator and prey.  Journal of Mammalogy 24:102–103.

Way, J.G.  2011.  Record pack-density of eastern coyotes/coywolves (Canis latrans x lycaon).  The American Midland Naturalist 165(1):201–203.

Webb, S.D.  1974.  Chronology of Florida Pleistocene mammals.  In: S.D. Webb (ed.), Pleistocene Mammals of Florida.  University Press of Florida, Gainesville, FL.

Wilson, L.D. and L. Porras.  1983.  The Ecological Impact of Man on the South Florida Herpetofauna.  The University of Kansas Museum of Natural History Special Publication No. 9, University of Kansas, Lawrence, KS.

Wooding, J.B. and T.S. Hardisky.  1990.  Coyote distribution in Florida.  Florida Field Naturalist 18:12–14.

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Oct
17

A Brief Summary of Laurel Wilt Disease in Florida and the Southeastern United States

Recently, there has been considerable interest and research regarding the laurel wilt disease, which affects members of the Lauraceae family, most notably red bay (Persea borbonia) and swamp bay (Persea palustris).  This article attempts to summarize the aspects of this disease that are of particular interest to land owners and land managers of Florida and elsewhere in the southeastern United States.

The Story of the Ambrosia Beetle, a Symbiotic Fungus, and the Disease Called Laurel Wilt

The disease Laurel wilt is spread by a nonindigenous beetle called the Asian red bay ambrosia beetle, Xyleborus glabratus.  This beetle measures only about 2 mm in length and is cigar-shaped and amber-brown to black in color.  This species has significantly less hair on its dorsal surface and is shinier than other species of ambrosia beetles.  The female ambrosia beetle spreads a nonindigenous fungus, Raffaelea lauricola, into the sapwood of a tree by boring pinhole-sized holes into the branches or trunk and either actively or passively depositing spores of the fungus in the tunnels.  The fungal spores are carried by the beetle in specialized pouch-like structures called ‘mycangia’ that are located at the base of each mandible.  Both adult and larval ambrosia beetles feed on the fungus growing in the tunnels.  Larvae are white with an amber-colored head.  Unlike most other species of ambrosia beetle, which attack dead or dying trees, the Asian red bay ambrosia beetle attacks healthy trees.  The native range of the fungus includes India, Japan, Taiwan, Burma, Bangladesh, and Myanmar.  As you probably guessed, the Asian red bay ambrosia beetle is native to Asia, including the same countries that the fungus is native to. 

The exact mechanism that causes death to a tree infected with the fungus and symbiont ambrosia beetle to die is unknown.  In simplified terms, the death of the tree is the result of it over-reacting to the presence of the pathogen.

The ambrosia beetle and associated fungus are thought to have arrived in the United States from Asia in untreated wood (such as wooden pallets) or in logs.  They were first detected in the United States in Port Wentworth near Savannah, Georgia, in May 2002.  The disease has since spread throughout the Southeast, from North Carolina south to Florida and west to Mississippi.

Relative Infestations of Laurel Wilt Disease among Infected States

State

Area of Coverage

Notes

Alabama

A few counties in the southwestern portion of the state

First detected in the state in 2011

Florida

Throughout most of the state

First detected in the state in 2005.  Not yet detected in some counties of the panhandle and in some the southwestern portion of the state

Georgia

Many counties in the southeastern portion of the state

First detected in the state in 2002, in Port Wentworth near Savannah

Mississippi

A few counties in the extreme southern part of the state

First detected in the state in 2009

North Carolina

Six counties in the southeastern portion of the state

First detected in the state in 2011

South Carolina

Many counties in the southern and eastern portions of the state

First detected in the state in 2004

What Tree Species Does Laurel Wilt Infect?

Although the beetle is named Asian red bay ambrosia beetle, it actually infects several other species, including both native trees and introduced trees of importance to the agricultural and ornamental plant industries.  Below is a list of species known to be susceptible to Laurel wilt.

Trees and Shrubs Known or Suspected to be Susceptible to Laurel Wilt Disease

Common Name

Scientific Name

Notes

Avocado

Persea americana

Introduced, important agricultural crop, important also to the ornamental plant trade

Lancewood

Ocotea coriacea

May be less susceptible to the disease than other members of the family, based on preliminary testing

Northern spicebush

Lindera benzoin

Pondspice

Litsea aestivalis

State-listed as endangered in Florida; demonstrated experimentally to be susceptible to the disease

Red bay

Persea borbonia

Sustained significant mortality due to the disease

Sassafrass

Sassafras albidum

Swamp bay
(incl. silk bay)

Persea palustris

Sustained significant mortality due to the disease

Southern spicebush (AKA pondberry)

Lindera melissifolia

State-listed as endangered in Florida; demonstrated experimentally to be susceptible to the disease

Summary of the Biology and Symptoms of Laurel Wilt Disease

The female ambrosia beetle, attracted to the smell of a red bay tree, bores into the branches or trunk of the tree and deposits spores of the fungus in the tunnels.  Initial symptoms are wilting of the leaves.  Often, wilting is seen in all the leaves associated with the distal portion of an infected branch.  More and more leaves begin to wilt over time as the disease progresses.  Mild discoloration may be seen in the sapwood and can escalate to extensive black/brown streaking over time.  Frass tubes, looking like white bent straws sticking out from the bark, begin to appear months later as beetle activity increases.  It can take as little as a week for a tree to die from laurel wilt during the warm summer months.

Both adult ambrosia beetles and their larvae feed on the fungus growing in the tunnels.  It takes some 30 days from the time the eggs hatch to the development of adult ambrosia beetles.  Males are smaller than females, lack wings, and are haploid.  Females are winged and are diploid.  The fungus can remain alive inside a standing dead tree for at least 1 year according to recent research.  The biology of laurel wilt disease remains poorly understood, and there is significant research to be done to understand the mechanisms involved in susceptibility and resistance.

Management and Prevention of Laurel Wilt Disease

It is no longer logistically feasible to eradicate or stop the progression of the disease considering how widely distributed it is in the southeastern United States.  However, one way to slow the spread on a given site is to cut down and chip dead trees killed by the disease and place the wood chips into piles.  The fungus was found to die about 2 days following chipping, and the ambrosia beetle population of the tree was found to be reduced by 99% following chipping.  The chipping will also reduce the wood available for female beetles to reproduce.

Use of the fungicide propiconazole (Alamo®), injected into the tree, was found to be only mildly effective (approximately 60% survivorship) at protecting red bay trees from the disease.  This treatment is expensive and testing for use against Laurel wilt has been limited so far.  Best results are achieved by systemic injection before any symptoms of the disease are observed on the tree and the pruning of any diseased areas following treatment.  Another method of injecting fungicide, developed by Arborjet®, involves delivering smaller amounts of fungicide using microinjectors.  The results of the effectiveness of the Arborjet® method have not been published as of this writing.  Similarly, the results of the effectiveness of applying fungicide to the soil around a tree have yet to be published.  Fungicides should be administered only by a knowledgeable professional or by the homeowner and in accordance with the instructions and mixing rates on the label.

Insecticides are unlikely to be useful at protecting a tree again the ambrosia beetle.  Broadcast spraying would be harmful to the environment and to beneficial insects, is not likely to be effective against the ambrosia beetle, and is therefore strongly discouraged. 

An attempt was made to protect some trees in Volusia County, Florida, by spraying Pinesol® as a way of “hiding” the trees from detection by the ambrosia beetle.  Pinesol® spraying took place at about 6‑ to 10‑week intervals.  However, all treated trees eventually contracted the disease and subsequently died.  It is possible that baits may be developed in the future that may be more attractive to the beetles than are the trees, but at this point in time no compounds have been identified for use as baits.

Anyone can help reduce the spread of the ambrosia beetle and the associated Laurel Wilt disease.  Refrain from moving untreated firewood far distances.  The State of Florida prohibits movement of untreated firewood farther than 50 miles within the state.  When camping, buy only local firewood or use certified firewood rather than bringing your own.  When traveling abroad, do not bring back untreated wood products or raw plant parts (including seeds or fruits).

Laurel wilt disease is one of at least a dozen tree diseases and insect pests within Florida or neighboring states.  Minimizing the movement of untreated wood and firewood can help reduce the spread of insect pests and diseases such as the emerald ash borer (kills ash trees), Asian longhorned beetle (kills maples), oak wilt and bot canker of oaks (kills oaks), spiraling whitefly (kills several native and ornamental trees), walnut twig beetle and thousand-cankers disease (kills walnuts), sudden oak death (kills oaks), and others.  The reader is encouraged to visit the website www.dontmovefirewood.org for more information.  

Sources and Further Reading:

Global Invasive Species Database.  2010.  Global Invasive Species Database, Raffaelea lauricola (fungus) [online database].  Accessed 10/17/2014 at http://www.issg.org/database/species/ecology.asp?si=1549&lang=EN.

Global Invasive Species Database.  2010.  Global Invasive Species Database, Xyleborus glabratus (insect) [online database].  Accessed 10/17/2014 at http://www.issg.org/database/species/ecology.asp?si=1536.

Spence, D. and J. Smith.  2013.  The status of Laurel Wilt.  Palmetto 30(3):4–5, 8–10. 

U.S. Department of Agriculture, Forest Service.  2013.  Laurel Wilt Distribution Map [online resource].  Accessed 10/17/2014 at http://www.fs.fed.us/r8/foresthealth/laurelwilt/dist_map.shtml.

 

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