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Introduction

White-tailed Deer

Coyotes

Canada Geese

Conclusion

References

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Human influences on coyote populations

Coyotes (Canis latrans) were unknown to the European settlers of America. The first written description of coyotes is from Lewis and Clark’s expedition in 1804. During this time, the range of coyotes was limited to the Great Plains. Over the past two hundred years, however, their range has greatly expanded across all of the U.S. Today, coyotes are even found in locations that are considered geographically isolated, such as Prince Edward Island and New York City (Gompper 2002b).

There are three predominant reasons why coyotes have been able to expand their range so greatly. First, one of the coyotes’ greatest predators, the gray wolf, has been wiped out from much of its former range. Due to habitat destruction and hunting, the wolf is now extirpated from much of the U.S. Second, the conversion of land through logging and agriculture has altered the landscape to a more favorable habitat for coyotes (Gompper 2002b). Third, humans relocated coyotes from the West. There are records of coyote releases in Maine, New York, New Jersey, Pennsylvania, and the Southeast (Gompper 2002a).

Although coyotes have spread their range due to land use changes, they are also sensitive to habitat fragmentation and isolation. Studies have found mixed results as to whether coyotes prefer natural or urbanized areas (Way et al. 2004). Regardless, they are highly adaptable animals. For instance, coyotes tend to be diurnal in natural areas and nocturnal in urbanized areas (Riley et al. 2003).

The increased range of coyotes has also increased the interaction of these animals and humans. Particularly in the Northeast, coyotes have been labeled as a nuisance because they forage in trashcans and kill pets and livestock. In addition, coyotes are the primary predator of sheep and have negatively impacted sheep farming in the U.S. (Berger 2006). Overall, it is estimated that coyotes cause between $4.4 and $27 million per year in economic losses due to livestock deaths. Furthermore, coyotes have attacked humans on rare occasions (Gompper 2002a).

Managing coyote populations is extremely difficult. Because the species is so adaptable, coyotes have quickly expanded their range. With few predators in the Northeast, coyotes are often the top predator and may influence many species. More research is needed on coyotes to determine better management practices.

Influences of coyotes on ecosystems

Coyotes are the top predator throughout much of the Northeast. The top-down effect is the ability of apex predators to disproportionately affect ecosystems. Now that coyotes are filling this niche in the Northeast, they are able to influence animal communities. In particular, coyotes may limit smaller carnivores (Gompper 2002b). For example, a study found that red foxes in eastern Maine limited their ranges to areas without coyotes. Coyotes spread into Maine after 1960 and have acted aggressively towards red foxes since this time. In response, red foxes have limited their habitats to forest fragments that are not part of core coyote territories (Harrison et al. 1989). Another study in Southern California found that small carnivore abundance was twice as high in fragments that coyotes did not visit than those locations where coyotes were detected (Crooks and Soulé 1999 ).

By influencing smaller carnivores, coyotes may indirectly affect bird communities. In the Southern California study, researchers found a positive relationship between coyotes and scrub bird populations. Scrub bird populations were higher in fragments were coyotes were detected because of the coyotes influence on mesopredators (Crooks and Soulé 1999 ). Coyotes have also encouraged the growth of communities of scavengers. For instance, ravens reestablished communities in the Adirondacks after coyote numbers increased in the area because they may feed off of carcasses killed by coyotes (Gompper 2002a). Overall, coyotes may disproportionately affect ecosystems when they are the apex predator.