Monday, September 27, 2010

Westchester County Coyotes

The Westchester County Parks Conservation Cafe lecture series recently presented a program entitled Coyotes in Suburbia.  This program and the high volume of attendees was no doubt the result of a summer punctuated with coyote-human interactions in and around the Rye, NY area.

For anyone not familiar with this summer's events, here's what happened:
June 25, 2010: A six-year old child was bit on the shoulder and back by one of two coyotes seen in her family's backyard in Rye, NY.
June 29, 2010: A three-year old child was bit on her torso by a single coyote in her backyard in Rye, NY.  The incident happened only a mile from the previous one.
September 5, 2010:  A teenager was lunged at but unharmed by a coyote at 6:50pm and a two-year old girl and her father were bitten by a coyote at 8pm the same evening a short distance away.  Both incidents took place in Rye Brook, NY.  The suspected coyote was ultimately put down and tests revealed it to be rabid.

In the wake of these events, a number of municipalities instituted trapping programs aimed at capturing and euthanizing coyotes.  The trapping projects were also aimed at "hazing" the local coyote populations to make them more fearful and cautious of humans.  In addition, local police were authorized to shoot coyotes whenever safely possible and local residents were given a number of guidelines and directions in regards to how to scare coyotes when an encounter occurs.

So all of this leads us to the Coyotes in Suburbia lecture held on Friday, September 24.  Three individuals involved in various research projects involving Eastern Coyotes presented their research on the species' genetics, behavior, and ecology.

Dr. Roland Kays of the New York State Museum presented "New York's Coyote/Coydog/Coywolf: What is it and how did it get here?".  His presentation covered the historical perspective of how the Eastern Coyote came to live throughout the Northeastern United States. 

In summary, Dr. Kays revealed the historical extirpation of various predator species (wolves, mountain lions, etc) from eastern forests as colonization expanded west.  In the early 1900's, land use, laws and perspectives on the value of wildlife, predators included, began to change and numerous wildlife species populations rebounded to reinhabit eastern forests.  Unfortunately, many predator populations were so ravaged that there was no chance of their species making a comeback, especially wolves. 

Dr. Kays explained that the gap in the food web was slowly replaced over time by the advance of two coyote populations moving east: one from Ohio and one from north of the Great Lakes.  Because of the lack of fossil evidence indicating the historical presence of coyotes in the Northeastern US, it was along these two "invasion" fronts that the coyote systematically colonized New York and the remainder of New England.  Dr. Kays' genetic studies also showed that Eastern Coyotes have low genetic diversity compared to Western and Ohio Coyotes.  This "founder effect" is strong evidence for the "invasion" theory.  The genetic mixing of Eastern and Ohio Coyote populations currently taking place in western NY/PA further supports this theory.

Dr. Kays' mitochondrial DNA studies indicate that Eastern Coyotes share a small portion of DNA similarity with Great Lakes wolf populations.  The coyote-wolf hybridization likely occurred as the Great Lakes coyotes traveled east through portions of the Great Lakes wolf population.  This supports the morphological studies comparing the skull sizes of Western, Ohio, and Eastern Coyotes.  On average, Eastern Coyotes' skulls are longer and wider than those of the Western and Ohio populations.

After Dr. Kays' presentation, Mark Weckel of the Mianus River Gorge presented some of the research he and a high school research associate completed titled "Mapping Human-Coyote Interaction in Westchester, NY".  Their project consisted of soliciting surveys to families throughout Westchester County, NY requesting information about coyote sightings on their property.  Using over 1,500 returned surveys, Mr. Weckel was able to assemble a map of the county that indicated the likelihood of encountering (i.e. seeing or hearing) a coyote.  Statistical analysis of the data showed that the survey data and associated map predicted the likelihood of a coyote encounter with a great deal of certainty.

Not coincidentally, the data indicated that a person's probability of an encounter increased with closer proximity to forest and grassland habitats and with increased distance from urban areas.  Mr. Weckel expressed that this isn't a shocking revelation, but it also indicates how unlikely it is for individuals to encounter a coyote in an urban/suburban environment.  This makes the unfortunate incidents in Rye and Rye Brook all the more extraordinary.  Further study is being conducted on urban/suburban coyote populations in the greater NY city area to continue to shed light on how coyotes use these human populated areas.

Finally, Dan Bogan, a doctoral candidate at Cornell University, presented some of the research he conducted as field research leader of the New York Urban/Suburban Coyote Study.  This NYSDEC-funded project was carried out in two northern Westchester and two southern Westchester municipalities.

Over the course of the project, a number of coyotes were trapped, radio-collared, and released so they could be tracked and recorded.  This was done to gain insight into how coyotes were establishing and utilizing home ranges within the study area.  While a number of the coyotes Mr. Bogan collared either emigrated far from the study area, died, or were "lost", the individuals that were studied extensively showed that they favored natural areas within the four municipalities and generally avoided areas considered urban/suburban.

Mr. Bogan's research into the dietary components of coyotes during the study revealed that the vast majority of urban/suburban coyotes diets included a heavy portion of white-tailed deer, rabbits, and a variety of other mammal species, birds, reptiles, amphibians, and plant matter.  There was no indication of coyotes utilizing human sources of food (i.e. garbage), and only on the rare occasion did they discover feline hair, bird seed, or strange items like latex and leather.  Bogan sighted the sample size as limited, but felt confident with the initial implications that coyotes are not extraordinarily habituated to humans or reliant upon human-generated sources of food.

At the end of a lively Q&A session, the morning's three presenters and DEC biologist Kevin Clarke generally came to the same conclusion: Coyotes are here, they're living in suburbia, and we will need to learn to live with them. 

As the lead DEC official responding to this summer's coyote incidents in Rye and Rye Brook, Mr. Clarke vehemently expressed that county residents must be proactive about avoiding negative coyote interactions.  He implored folks to eliminate/modify their behaviors and features of their landscape which are likely to increase the chance of a negative coyote interaction.  Here are the NYDEC's tips on avoiding conflicts with coyotes.

And finally, I'd like to add that the coyote, and the remainder of the wildlife in our region, are a sign of our area's ecological strength.  As many of us visit parks, preserves and nature sanctuaries, its important that we remember that our suburban homes and neighborhoods are extensions of these wild places.  Wildlife species do not recognize park boundaries and we all inhabit the same place.

-Adam Zorn, Naturalist

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