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Interactions between bobcats and coyotes
Topic Started: Jan 13 2012, 11:39 PM (7,964 Views)
Taipan
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Gato gordo
 
The coyote-bobcat interaction is facinating because it involves two competing sympatric predator species that are relatively close in weight. I have read the following articles on this interaction:

- Litvaitis, J.A. and D.J. Harrison. 1989. Bobcat-coyote niche relationships during a period of coyote population increase. Can. J. Zool. 67:1180-1188.

- Major, J.T. and J.A. Sherburne. 1987. Interspecific relationships of coyotes, bobcats, and red foxes in western Maine. J. Wildl. Manage. 51:606-616.

- Knick, S. T. 1990. Ecology of bobcats relative to exploitation and a prey decline in southeastern Idaho. Wildlife Monographs 108:1–42.


These articles are very much cited in the study of relations between competing predators. The context of the first two articles is to study the effect on bobcat resident populations by coyotes, which just recently re-colonized the North East of the USA. The article by Knick is quoted by the study on interspecies killing among predators (by Palomares and Caro) as evidence that coyotes kill bobcats.

However, either in Maine or Idaho or Colorado coyotes do hunt deer (at least in winter) in pairs or packs, so the killed bobcats reported by Knick (two out of about a dozen mortalities) were most likely killed by more than one coyote.

I have read other studies of this relation in Colorado, Florida, Arizona and Texas. The Colorado study does report dead bobcats, but the Florida, Arizona and Texas studies do not report any agressive interaction: mostly self avoidance with prey/terrain segregation.

There is a study of the relation between coyotes, foxes and bobcats in the Santa Monica area in California, reporting two dead adult bobcats (a male and a female, out of 5 total mortalities). This study is available in the web: just type in google "intraguild predation" and "coyote" and "bobcat".

This is the abstract of the Litvaitis-Harrison paper:

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The following extract mentions that bobcats and coyotes do overlap in their territories. The authors mention that their study did not detect directly any single interaction between them, and the only casualty they report is a male bobcat immobilized by a leg hold trap that was killed by two coyotes. They conclude that the pattern is that of mutual avoidance.

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The following extract mentions that bobcats prefer thick forested regions because this suits their stalking strategy, but also because this terrain to take cover against possible coyote's attacks.

The extracts also mentions other studies where bobcats were found killed by coyotes: by Anderson 1986, Jackson 1986 and Toweil 1986. Notice the summary of what Anderson reports:

- coyotes killed three juveniles and an adult female
- juveniles and females were rarely more than 100 mts away from trees

However, adult male bobcats often foraged in more open areas, which (according to Anderson) suggests that large bobcats may not be vulnerable to coyote predation.

However, Litvaitis and Harrison found (after tracking them for 44 km) that bobcats in their study did not travel more than 100 mts away from trees.

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The following two extracts show the (possible) effects of the presence of coyotes in the diet of bobcats. Before coyotes' re-colonization bobcats hunted more deer and now they have specialized in snowshoe hare. This may be a direct effect of coyotes out-competing bobcats.

However, the second extract gives alternative explanations: perhaps the deer population was more abundant before and diminished by reaons that have nothing to do with the coyotes, or perhaps coyotes are simply more efficient deer hunters for working as a team.

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The following extract is EXTREMELY EDUCATIVE: it explains the difference between "exploitation" and "interference" types of competition. In the former a species is just more efficient in using resources and does not (necessarily) involve any agressive physical interaction, or even any concious action to deprive these resources to the other species. In the second type, one species actively denies such use, by physical or chemical mechanisms.

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The following extract gives examples of "interference" competition between wolves vs coyotes and coyotes vs foxes, resulting in the spacial displacement of the "looser" species. In the case of coyotes and bobcats such a spacial displacement is not seen, suggesting mostly an "exploitative" type of dominance by coyotes and bobcats.

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The following extract explains what may be the compatitive advantages of coyotes over bobcats. Bobcat's survival in winter strongly depends on prey availability. Since deer and deer carcasses are the main winter prey, this has a direct influence on bobcats' physical condition.

Besides:

- coyotes seem to be better adapted to northern latitudes
- coyotes hunt as a team
- coyotes have larger litters

So, coyotes may be more efficient in hunting winter deer and will deplete this prey for the bobcats, which may starve or leave the area.

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The following extract provides the authors' concusions: while coyotes may be more efficient predators of deer, bobcats have shifted to snowshoe hare and remain efficient predators in the dense cover areas that they favor.

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MY CONCLUSION

Except for the Santa Monica study, in all areas where bobcats have been found killed by coyotes (Colorado, Idaho) it is very likely the coyotes acted as a pair or small pack, because coyotes in these areas hunt seasonally deer acting in pais or small packs. In Santa Monica this is not the case, since both coyotes and bobcats have the same prey base of small game.

IMO an average coyote is 40-50% larger than an average bobcat, so that a large bobcat tom is close in weight to a female coyote, but a male coyote is almost twice as heavy as a female bobcat. At average weights the coyote should (most likely) win an agressive encounter but at a high cost. A competitor between 1/2 to 2/3 of the weight of a land mammal predator is already too risky and agressive interactions arelilely to be very few. This is IMO behind the fact that scientific studies tend to show "exploitative" coyote dominance under a mutual avoidance pattern. My guess is that most cases of coyotes killing bobcats involve the action of a pair, and/or a coyote having signifficant weight edge (a male coyote vs a female bobcat). In the cases involving possibly a single coyote (in Santa Monica) it is likely IMO that the dead bobcats were stalked/ambushed or that there was also a relatively large weight edge for the coyote.



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Taipan
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reddhole
 
I largely agree with Gato's analysis except for a couple of minor items.

1) A more recent and large-scale study of coyote predation on deer showed single coyotes doing a significant number of such kills. I will post this information in the coming days hopefully.

2) I think the coyote predations on bobcats were done by either 1 or 2 coyotes. Most coyote packs are a mated pair or a mated pair with puppies; indicating 1 or both of the adults would be involved in such killings. I had emailed a researcher associated with lynx, fisher, and coyote studies from Maine who indicated that coyotes would most likely kill another predator in a group of 1 or 2 members.

3) I have a few other studies of coyotes and bobcats; and generally speaking some show some spatial displacement of bobcats. However, in just about everyone the coyote was the dominant predator - though as Gato said the animals were close enough matched for such dominance to be slight and predations to be rare.

4) A more recent account of coyote predation on bobcat from the scientific journal the Southwestern Naturalist is presented below, which showed a healthy prime-aged female bobcat killed by "1 or more" coyotes.

IMHO, it was likely a single coyote because a "bite and shake" hold was used, which is typical of a single canid killing an animal. Of course, I could be wrong and I'm probobly biased here! :)

Gipson, P. S., and J. F. Kamler. 2002. Bobcat killed by a coyote. Southwestern Naturalist 47:511-513

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Taipan
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Interesting to note in the above article it states - "only relatively small bobcats, such as adult females and juveniles, were reportedly killed by coyotes."


"It has long been believed that coyotes outcompete bobcats, resulting in reduced populations of bobcats. Major and Sherburne (1987), conducting research in Maine, indicated that coyotes and bobcats shared home ranges, habitat use, and diets, but there was no data to support interference competition. Coyote and bobcat diets and habitat use overlapped in Oregon, however there was little competition between the two because prey populations were high (Witmer and deCalesta 1986).

Litvaitis and Harrison (1989) studied bobcat-coyote relationships during a period of coyote expansion in Maine. Seasonal habitat use by coyotes varied more than bobcats, perhaps because of the greater variety of food items in coyote diets. They also indicate that bobcat food habits have changed since the arrival of coyotes to Maine.

Litvaitis and Harrison (1989) found that coyotes did not displace or exclude bobcats. They speculated that coyotes have reduced the carrying capacity of bobcats by reducing prey availability and suggested that bobcat numbers will decline and stabilize at lower densities as a result of increasing coyote densities. They also report one incident of coyotes preying on a bobcat. Under the right circumstances it is not impossible for a coyote or group of coyotes to kill a bobcat."
http://texnat.tamu.edu/symposia/coyote/p6.htm

What might those circumstances be?

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Taipan
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reddhole
 
I favor the coyote based on the scientific literature and my personal belief that medium-sized canids beat (or draw) small felids. As far as I know, there are no cases of bobcats killing coyotes.

http://www.wildcru.org/aboutus/people/kamler_pdfs/2002-3.pdf

Coyotes {Canis latrans) and bobcats {Lynx ru-fus) are often killed by larger carnivores, including wolves (Canis lupus) and cougars {Felisconcolor) (Koehler and Hornocker, 1991; Peterson, 1995). Although interspecific strife between coyotes and bobcats has been inferred(Litvaitis and Harrison, 1989), there are few documented instances of aggressive behavior between these 2 similarly-sized species. Here, we describe characteristics of an adult female bobcat that was likely killed by 1 or more coyotes in Kansas.

Interspecific prédation between coyotes and bobcats might put either species at risk of injury, because they are more similar in size to each other than to other carnivores. However, coyotes tend to be slightly larger than bobcats (Bekoff, 1982; McCord and Cardoza, 1982), and numbers of bobcats have been negatively correlated to numbers of coyotes in several regions in North America (Robinson, 1961; Nunley, 1978; Litvaitis and Harrison, 1989), suggesting that coyotes suppress bobcat popula-tions. Coyotes might suppress bobcat populations by exploitation competition (greater use f resources) or interference competition (direct prédation) (Litvaitis and Harrison, 1989;Buskirk et al., 2000), although there is littlee idence for either. Interference competition mong carnivores may be greatest when 2 species are similar in size, but 1 species is typically arger than the other (Buskirk et al., 2000), as s the case with coyotes and bobcats.

In Idaho, (Knick (1990) documented 2 bobcats that were killed by coyotes, although he did not provide any additional information. Toweill (1986) documented 1 case in Oregon where a juvenile female bobcat was killed by a coyote. In southeastern Colorado, Anderson (1987) reported that 1 adult female and 3 juvenile (1 male, 2 female) bobcats were killed by predators. Evidence at the kill sites (caching and scratch marks) suggested that coyotes had killed those bobcats (Anderson, 1987). Similarly, in east-central Colorado, Jackson (1986) re-ported that 5 female (4 adult, 1 juvenile) bobcats were killed by predators, although he did not specify the predator species. Interestingly,only relatively small bobcats, such as adult females and juveniles, were reportedly killed by coyotes.

On 10 February 1999, we recovered the carcass of an adult female bobcat that had been radio-collared since October 1995 as part of alarger study on Fort Riley Military Reservationin northeastern Kansas (Kamler, 1998). This bobcat was approximately 5 to 7 years old and had not exhibited any unusual movements prior to her death. Bite marks were observed near the head, neck, and chest area of the carcass,which had not been consumed. The skeleton of the bobcat was cleaned with a digestive en-yme solution. From subsequent inspection ofthe skeletal remains we inferred that the bobcat had been killed by another carnivore. Size and spacing of canine puncture wounds on the skull and both scapulas matched that of a coyote. In addition to puncture holes at the rear of the skull, the left jugal bone was broken in 2 places. Bite marks occurred on most of the ribs, with a minimum of 13 broken ribs. Several bite marks were observed on the right hindlimb, with a fracture on the fibula.
This specimen is deposited at the Museum of Natural History, University of Kansas, Lawrence.

An alternative explanation is that feral dogs{Canis familiaris) had killed the bobcat, because feral dogs had been observed on Fort Riley. However, we think that coyotes are the more likely predators because: 1) densities ofcoyotes (0.8 to 0.9/km2) and bobcats (0.4 to0.5/km2) on Fort Riley were relatively high(Kamler, 1998; Kamler and Gipson, 2000), and thus competition between the 2 species was likely great, 2) bite mark characteristics on the bobcat were similar to those found on opos-sums (Didelphis virginiana) and raccoons (Pro-cyon lotor) that were known to have been killed by coyotes on Fort Riley (Kamler, 1998), and 3) wounds on the bobcat were indicative of a bite and shake attack method known to beused by coyotes and wolves on medium-sized prey (Allen, 1979; Anderson, 1987; White andBoyd, 1989; Disney and Spiegel, 1992).

At our study site, body masses (mean ± SE) of male coyotes, 13.3 ± 0.4 kg (n = 5), and female coyotes, 11.6 ± 0.4 kg (n = 8), were larger than those of female bobcats 8.3 ± 0.2kg (n = 4). Thus, coyotes could potentially at-tack and kill female bobcats because body size often determines the outcome during interspecific conflicts (Palomares and Caro, 1999; Buskirk et al., 2000). Because the bobcat carcass was not eaten, it is doubtful that it was killed for food. A more likely explanation was that the bobcat was killed to reduce competition for limited resources. Palomares and Caro(1999) showed that most interspecific killingsamong carnivores occurred during winter,when availability of prey decreases and com-petition among carnivores increases.
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Taipan
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taipan
 
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Bobcat and Coyote .
This was in West Texas. The Bobcat had killed two Coyote before being killed by this Coyote. This is pure nature at its best or worse.
http://photo.net/photodb/photo?photo_id=2935985

What do we think?
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reddhole
 
This is the study from the Santa Monica Mountains mentioned by Gato.


http://www.springerlink.com/content/6u7mut7vgrhb6kug/

Abstract

We examined the relative roles of dominance in agonistic interactions and energetic constraints related to body size in determining local abundances of coyotes (Canis latrans, 8-20 kg), gray foxes (Urocyon cinereoargenteus, 3-5 kg) and bobcats (Felis rufus, 5-15 kg) at three study sites (hereafter referred to as NP, CP, and SP) in the Santa Monica Mountains of California. We hypothesized that the largest and behaviorally dominant species, the coyote, would exploit a wider range of resources (i.e., a higher number of habitat and/or food types) and, consequently, would occur in higher density than the other two carnivores. We evaluated our hypotheses by quantifying their diets, food overlap, habitat-specific abundances, as well as their overall relative abundance at the three study sites. We identified behavioral dominance of coyotes over foxes and bobcats in Santa Monica because 7 of 12 recorded gray fox deaths and 2 of 5 recorded bobcat deaths were due to coyote predation, and no coyotes died as a result of their interactions with bobcats or foxes. Coyotes and bobcats were present in a variety of habitats types (8 out of 9), including both open and brushy habitats, whereas gray foxes were chiefly restricted to brushy habitats. There was a negative relationship between the abundances of coyotes and gray foxes (P=0.020) across habitats, suggesting that foxes avoided habitats of high coyote predation risk. Coyote abundance was low in NP, high in CP, and intermediate in SP. Bobcat abundance changed little across study sites, and gray foxes were very abundant in NP, absent in CP, and scarce in SP; this suggests a negative relationship between coyote and fox abundances across study sites, as well. Bobcats were solely carnivorous, relying on small mammals (lagomorphs and rodents) throughout the year and at all three sites. Coyotes and gray foxes also relied on small mammals year-round at all sites, though they also ate significant amounts of fruit. Though there were strong overall interspecific differences in food habits of carnivores (P<0.0001), average seasonal food overlaps were high due to the importance of small mammals in all carnivore diets [bobcat-gray fox: 0.79-0.09 (SD), n=4; bobcat-coyote: 0.69-0.16, n=6; coyote-gray fox: 0.52-0.05, n=4]. As hypothesized, coyotes used more food types and more habitat types than did bobcats and gray foxes and, overall, coyotes were the most abundant of the three species and ranged more widely than did gray foxes. We propose that coyotes limit the number and distribution of gray foxes in Santa Monica Mountains, and that those two carnivores exemplified a case in which the relationship between their body size and local abundance is governed by competitive dominance of the largest species rather than by energetic equivalences. However, in the case of the intermediate-sized bobcat no such a pattern emerged, likely due to rarity or inconsistency of agonistic interactions and/or behavioral avoidance of encounters by subordinate species.

A relevant section:


Twelve radio-tagged gray foxes were found dead in
2 years of study; seven were killed by coyotes and two
by bobcats (V. Farias, T.K. Fuller, J.M. Fedriani, R.B.
Wayne, R.M. Sauvajot, unpublished work). All sexes
and ages of gray foxes suffered carnivore predation. Of a total of five radio-tagged bobcats deaths, two (male and female, both adult) were due to coyote predation.

In addition, remains of bobcats and gray foxes were found in
coyote feces (4 and 2 cases, respectively). Evidence of
cannibalism was also detected; one coyote was found
dead that was killed by conspecifics, and remains of bobcats
in one bobcat scat and remains of gray foxes in one
gray fox scat were also found. Evidence of interference among carnivores involving non-targeted species included the death of a radio-tagged adult male coyote probably
killed by a mountain lion (Felis concolor), an American badger (Taxidea taxus) killed by coyote,
and the remains
of spotted skunk (Spilogale putorius) and longtailed
weasel (Mustela frenata) in feces of coyotes (1 case)
and bobcats (2 cases), respectively.
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Taipan
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taipan
 
reddhole
 



Jan Kamler states that an approximate 40% - 60% body size advantage is enough for a coyote to kill a bobcat in his paper documenting coyote predation on an adult female bobcat:
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I emailed Dr Jan Kamler a while ago. Here is part of his response :

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Dr Crabtree provided a similar response to the outcome of an encounter in his email, but did not go into as much detail on the issue.
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This coyote was one of 3 that tried to harrass a bobcat. I don't think they were successful. This one was the only one I was able to get in a frame with the cat

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This coyote was waiting for help from 2 other coyotes. Help never came.

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The coyote is still waiting for help from 2 other coyotes, and the cat continues to keep an eye on him. These 2 walked over the hill very close together, but friends they were not!

http://www.eyefetch.com/image.aspx?ID=710021
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Picture from Scottwolverine1111

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manics
 
Edited by Taipan, Jan 13 2012, 11:59 PM.
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http://www.capturekerncounty.com/photos/284117
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FelinePowah
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[ *  *  *  *  *  *  * ]
What parts of America has the biggist bobcats?
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Canidae
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FelinePowah
Jan 14 2012, 06:21 AM
What parts of America has the biggist bobcats?
The largest was shot in Wisconsin, though I think Northern / Canadian ones are largest in general.
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Gato Gordo
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Now that I have more spare time I continue passing more informative threads from the old forum. This thread contains a summery of the literature on the bobcat vs coyote interaction in various habitats in the USA. None of the articles answer the "who would win" question, but the information can be useful to assess this match.


The coyote-bobcat interaction is fascinating because it involves two competing sympatric (common habitat) predator species that are relatively close in weight. I can directly cite the following articles on this interaction:

--- Litvaitis, J.A. and D.J. Harrison. 1989. Bobcat-coyote niche relationships during a period of coyote population increase. Can. J. Zool. 67:1180-1188.

--- Major, J.T. and J.A. Sherburne. 1987. Interspecific relationships of coyotes, bobcats, and red foxes in western Maine. J. Wildl. Manage. 51:606-616.

--- Knick, S. T. 1990. Ecology of bobcats relative to exploitation and a prey decline in southeastern Idaho. Wildlife Monographs 108:1–42.

--- Gipson P. S. 2002 and Kamler J. F. Bobcat killed by a coyote
The Southwestern Naturalist, vol. 47, no. 3 pp 511-512

--- Fedriani J. M., Fuller T. K., Sauvajot R. M. and York E. C. Competition and intraguild predation among three sympatric carnivores Oecologia, Volume 125, Number 2 / October, 2000, pp 258-270


These articles are very much cited in the study of relations between competing predators. The context of the first two articles is to study the effect on bobcat resident populations by coyotes, which just recently re-colonized the North East of the USA.

The article by Knick is quoted by the study on interspecies killing among predators (by Palomares and Caro) as evidence that coyotes kill bobcats.

The article by Gipson and Kamler (available to download) describes an actual case of intraguild predation by one (or more) coyote(s) on a 5-7 year old radio-collared female bobcat in Fort Riley, Kansas. It is (or at least was) available at http://www.wildcru.org/aboutus/people/kamler_pdfs/2002-3.pdf

The article by Fedriani et al is a study of the relation between coyotes, foxes and bobcats in the Santa Monica area in California, reporting two dead adult bobcats (a male and a female, out of 5 total mortalities). This study is available in the web, but the google search to find it can be long.

I have read other studies of this relation in Colorado, Florida, Arizona and Texas. The Colorado study does report dead bobcats, but there is no detail on the predators that killed them. The Florida, Arizona and Texas studies do not report any agressive interaction: mostly self avoidance with prey/terrain segregation.

However, either in Maine or Idaho or Colorado coyotes do hunt deer (at least in winter) in pairs or packs, and (as far as I can tell) bobcat fatalities were in winter. So the killed bobcats reported by Knick (two out of about a dozen mortalities) were most likely killed by more than one coyote. Likewise, the female bobcat in Fort Riley (a winter kill in February) could have been killed by more than one coyote.

I will post below in separate posts:

-- The abstract of the Santa Monica Study (Fedriani et al)
-- The full text of the article by Gipson and Kamler
-- Extracts of the article by Litvaitis and Harrison


THE SANTA MONICA STUDY:


We examined the relative roles of dominance in agonistic interactions and energetic constraints related to body size in determining local abundances of coyotes (Canis latrans, 8-20 kg), gray foxes (Urocyon cinereoargenteus, 3-5 kg) and bobcats (Felis rufus, 5-15 kg) at three study sites (hereafter referred to as NP, CP, and SP) in the Santa Monica Mountains of California. We hypothesized that the largest and behaviorally dominant species, the coyote, would exploit a wider range of resources (i.e., a higher number of habitat and/or food types) and, consequently, would occur in higher density than the other two carnivores. We evaluated our hypotheses by quantifying their diets, food overlap, habitat-specific abundances, as well as their overall relative abundance at the three study sites.

We identified behavioral dominance of coyotes over foxes and bobcats in Santa Monica because 7 of 12 recorded gray fox deaths and 2 of 5 recorded bobcat deaths were due to coyote predation, and no coyotes died as a result of their interactions with bobcats or foxes. Coyotes and bobcats were present in a variety of habitats types (8 out of 9), including both open and brushy habitats, whereas gray foxes were chiefly restricted to brushy habitats. There was a negative relationship between the abundances of coyotes and gray foxes (P=0.020) across habitats, suggesting that foxes avoided habitats of high coyote predation risk. Coyote abundance was low in NP, high in CP, and intermediate in SP. Bobcat abundance changed little across study sites, and gray foxes were very abundant in NP, absent in CP, and scarce in SP; this suggests a negative relationship between coyote and fox abundances across study sites, as well. Bobcats were solely carnivorous, relying on small mammals (lagomorphs and rodents) throughout the year and at all three sites. Coyotes and gray foxes also relied on small mammals year-round at all sites, though they also ate significant amounts of fruit. Though there were strong overall interspecific differences in food habits of carnivores (P<0.0001), average seasonal food overlaps were high due to the importance of small mammals in all carnivore diets [bobcat-gray fox: 0.79-0.09 (SD), n=4; bobcat-coyote: 0.69-0.16, n=6; coyote-gray fox: 0.52-0.05, n=4].

As hypothesized, coyotes used more food types and more habitat types than did bobcats and gray foxes and, overall, coyotes were the most abundant of the three species and ranged more widely than did gray foxes. We propose that coyotes limit the number and distribution of gray foxes in Santa Monica Mountains, and that those two carnivores exemplified a case in which the relationship between their body size and local abundance is governed by competitive dominance of the largest species rather than by energetic equivalences. However, in the case of the intermediate-sized bobcat no such a pattern emerged, likely due to rarity or inconsistency of agonistic interactions and/or behavioral avoidance of encounters by subordinate species.

THE STUDY AT FORT RILEY, KANSAS

Coyotes {Canis latrans) and bobcats {Lynx ru-
fus) are often killed by larger carnivores, in-
cluding wolves ( Canis lupus) and cougars {Felis
concolor) (Koehler and Hornocker, 1991; Peter-
son, 1995). Although interspecific strife be-
tween coyotes and bobcats has been inferred
(Litvaitis and Harrison, 1989), there are few
documented instances of aggressive behavior
between these 2 similarly-sized species. Here,
we describe characteristics of an adult female
bobcat that was likely killed by 1 or more coy-
otes in Kansas.

Interspecific predation between coyotes and
bobcats might put either species at risk of in-
jury, because they are more similar in size to
each other than to other carnivores. However,
coyotes tend to be slightly larger than bobcats
(Bekoff, 1982; McCord and Cardoza, 1982),
and numbers of bobcats have been negatively
correlated to numbers of coyotes in several re-
gions in North America (Robinson, 1961; Nun-
ley, 1978; Litvaitis and Harrison, 1989), sug-
gesting that coyotes suppress bobcat popula-
tions. Coyotes might suppress bobcat popula-
tions by exploitation competition (greater use
of resources) or interference competition (di-
rect prédation) (Litvaitis and Harrison, 1989;
Buskirk et al., 2000), although there is little
evidence for either. Interference competition
among carnivores may be greatest when 2 spe-
cies are similar in size, but 1 species is typically
larger than the other (Buskirk et al., 2000), as
is the case with coyotes and bobcats.

In Idaho, Knick (1990) documented 2 bob-
cats that were killed by coyotes, although he
did not provide any additional information.
Toweill (1986) documented 1 case in Oregon
where a juvenile female bobcat was killed by a
coyote. In southeastern Colorado, Anderson
(1987) reported that 1 adult female and 3 ju-
venile (1 male, 2 female) bobcats were killed
by predators. Evidence at the kill sites (caching
and scratch marks) suggested that coyotes had
killed those bobcats (Anderson, 1987). Similar-
ly, in east-central Colorado, Jackson (1986) re-
ported that 5 female (4 adult, 1 juvenile) bob-
cats were killed by predators, although he did
not specify the predator species. Interestingly,
only relatively small bobcats, such as adult fe-
males and juveniles, were reportedly killed by
coyotes.

On 10 February 1999 we recovered the car-
cass of an adult female bobcat that had been
radio-collared since October 1995 as part of a
larger study on Fort Riley Military Reservation
in northeastern Kansas (Kamler, 1998). This
bobcat was approximately 5 to 7 years old and
had not exhibited any unusual movements pri-
or to her death. Bite marks were observed near
the head, neck, and chest area of the carcass,
which had not been consumed. The skeleton
of the bobcat was cleaned with a digestive en-
zyme solution. From subsequent inspection of
the skeletal remains we inferred that the bob-
cat had been killed by another carnivore. Size
and spacing of canine puncture wounds on the
skull and both scapulas matched that of a coy-
ote. In addition to puncture holes at the rear
of the skull, the left jugal bone was broken in
2 places. Bite marks occurred on most of the
ribs, with a minimum of 13 broken ribs. Several
bite marks were observed on the right hind
limb, with a fracture on the fibula. This speci-
men is deposited at the Museum of Natural
History, University of Kansas, Lawrence.

An alternative explanation is that feral dogs
(Canis familiaris) had killed the bobcat, be-
cause feral dogs had been observed on Fort
Riley. However, we think that coyotes are the
more likely predators because: 1) densities of
coyotes (0.8 to 0.9/km2) and bobcats (0.4 to
0.5/km2) on Fort Riley were relatively high
(Kamler, 1998; Kamler and Gipson, 2000), and
thus competition between the 2 species was
likely great, 2) bite mark characteristics on the
bobcat were similar to those found on opos-
sums (Didelphis virginiana) and raccoons (Pro-
cyon lotor) that were known to have been killed
by coyotes on Fort Riley (Kamler, 1998), and
3) wounds on the bobcat were indicative of a
bite and shake attack method known to be
used by coyotes and wolves on medium-sized
prey (Allen, 1979; Anderson, 1987; White and
Boyd, 1989; Disney and Spiegel, 1992).

At our study site, body masses (mean ± SE)
of male coyotes, 13.3 ± 0.4 kg (n = 5), and
female coyotes, 11.6 ± 0.4 kg (n = 8), were
larger than those of female bobcats 8.3 ± 0.2
kg (n = 4). Thus, coyotes could potentially at-
tack and kill female bobcats because body size
often determines the outcome during interspe-
cific conflicts
(Palomares and Caro, 1999; Bus-
kirk et al., 2000). Because the bobcat carcass
was not eaten, it is doubtful that it was killed
for food. A more likely explanation was that
the bobcat was killed to reduce competition
for limited resources. Palomares and Caro
(1999) showed that most interspecific killings
among carnivores occurred during winter,
when availability of prey decreases and com-
petition among carnivores increases.

THE LITVAITIS--HARRISON ARTICLE


This is the abstract of the Litvaitis-Harrison paper:

Posted Image


The following extract mentions that bobcats and coyotes do overlap in their territories. The authors mention that their study did not detect directly any single interaction between them, and the only casualty they report is a male bobcat immobilized by a leg hold trap that was killed by two coyotes. They conclude that the pattern is that of mutual avoidance.

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The following extract mentions that bobcats prefer thick forested regions because this suits their stalking strategy, but also because this terrain to take cover against possible coyote's attacks.

The extracts also mentions other studies where bobcats were found killed by coyotes: by Anderson 1986, Jackson 1986 and Toweil 1986. Notice the summary of what Anderson reports:

--- coyotes killed three juveniles and an adult female
--- juveniles and females were rarely more than 100 mts away from trees

However, adult male bobcats often foraged in more open areas, which (according to Anderson) suggests that large bobcats may not be vulnerable to coyote predation.

Yet, Litvaitis and Harrison found (after tracking them for 44 km) that bobcats in their study did not travel more than 100 mts away from trees.

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The following two extracts show the (possible) effects of the presence of coyotes in the diet of bobcats. Before coyotes' re-colonization bobcats hunted more deer and now they have specialized in snowshoe hare. This may be a direct effect of coyotes out-competing bobcats.

However, the second extract gives alternative explanations: perhaps the deer population was more abundant before and diminished by reasons that have nothing to do with the coyotes, or perhaps coyotes are simply more efficient deer hunters for working as a team.

Posted Image
Posted Image


The following extract is EXTREMELY EDUCATIVE: it explains the difference between "exploitation" and "interference" types of competition. In the former a species is just more efficient in using resources and does not (necessarily) involve any aggressive physical interaction, or even any conscious action to deprive these resources to the other species. In the second type, one species actively denies such use, by physical or chemical mechanisms.

Posted Image

The following extract gives examples of "interference" competition between wolves vs coyotes and coyotes vs foxes, resulting in the spacial displacement of the "looser" species. In the case of coyotes and bobcats such a spacial displacement is not seen, suggesting mostly an "exploitative" type of dominance by coyotes and bobcats.

Posted Image

The following extract explains what may be the competitive advantages of coyotes over bobcats. Bobcat's survival in winter strongly depends on prey availability. Since deer and deer carcasses are the main winter prey, this has a direct influence on bobcats' physical condition.

Besides:

-- coyotes seem to be better adapted to northern latitudes
-- coyotes hunt as a team
-- coyotes have larger litters

So, coyotes may be more efficient in hunting winter deer and will deplete this prey for the bobcats, which may starve or leave the area.

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The following extract provides the authors' conclusions: while coyotes may be more efficient predators of deer, bobcats have shifted to snowshoe hare and remain efficient predators in the dense cover areas that they favor.

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MY COMMENTS:

Except for the Santa Monica study, in all areas where bobcats have been found killed by coyotes (Colorado, Idaho) it is very likely the coyotes acted as a pair or small pack, because coyotes in these areas hunt seasonally deer acting in pairs or small packs. In Santa Monica this is not the case, since both coyotes and bobcats have the same prey base of small game.

IMO an average coyote male is at least 20%-30% larger than an average bobcat male, so that a bobcat tom is close in weight to a female coyote, but a male coyote is 60-100% (approaching 2X) as heavy as a female bobcat. At average weights a frontal fight between the male or female coyote and the male bobcat would be very risky, and even if it could be won by the larger male coyote (a good guess), it would be IMO at a high cost for the canid, too high to explain why one on one male-male encounters should be very very rare. The size edge is more (and so the risk is less) for a male coyote attacking a female or juvenile bobcat. Obviously, two coyotes would find it less risky as well. This is in general terms supported by all articles, for example:

From Gipson and Kamler:

At our study site, body masses (mean ± SE)
of male coyotes, 13.3 ± 0.4 kg (n = 5), and
female coyotes, 11.6 ± 0.4 kg (n = 8), were
larger than those of female bobcats 8.3 ± 0.2
kg (n = 4). Thus, coyotes could potentially at-
tack and kill female bobcats because body size
often determines the outcome during interspe-
cific conflicts (Palomares and Caro, 1999; Bus-
kirk et al., 2000).


This close sized relation is IMO behind the fact that scientific studies tend to show "exploitative" coyote dominance under a mutual avoidance pattern. In the Maine study by Litvaitis-Harrison coyotes and bobcats lived at low densities, and this pattern was predominant. However, antagonistic interactions can occur in higher densities when resources are scarce in winter (as in the Gipson-Kamler study):

Because the bobcat carcass
was not eaten, it is doubtful that it was killed
for food. A more likely explanation was that
the bobcat was killed to reduce competition
for limited resources. Palomares and Caro
(1999) showed that most interspecific killings
among carnivores occurred during winter,
when availability of prey decreases and com-
petition among carnivores increases.

My guess is that most cases of coyotes killing bobcats have involved ether a pair of coyotes, and/or a male coyote with a significant weight edge (a male coyote vs a female bobcat). The exception is likely the Santa Monica case because western coyotes in the area tend to forage alone.

Notice that in practically all reported cases bobcats killed by coyotes were low end specimens or in disadvantage (the trapped bobcat in the Litvaitis-Harrison study). The exception is the Santa Monica study, where two adults (a male and a female) were killed. My guess is that these dead bobcats were smaller adults, but this is just my guess.

Finally: it is interesting to remark that bobcats have not been recorded as causing a single coyote mortality, not even pups. However, there is a record of bobcat predation on an adult badger, which is harder to kill than a substandard coyote. This shows that the lack of bobcat predation on low end coyotes is not because they can't kill them, but IMO it follows from the fact that (i) coyote pups are never alone (ii) given the weight/size edge of coyotes even a juvenile coyote is risky enough and (iii) bobcats are always solitary while coyotes in all populations can forage in pairs or groups at least part of the time (even if in some habitats they forage alone most times).


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Gato Gordo
Heterotrophic Organism
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Hey Taipan, I didn't know that you had already passed this thread to the new site. Anyway, let's hope that it serves as a good reference in our debates.
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