On another forum, we are discussing red fox populations, and reasons for them being displaced (or not) by coyotes. In other words- is the expansion of the coyote (really both western and eastern)the dominant factor in the decreased red fox populations that most of the country is seeing? I believe that it is most likely so. But the information I have been able to dig up through surfing (even falling back on gopher, Archie etc LOL-lot of dead ends in that system!) hasn't been conclusive. Many studies hint or say "research shows.. but never give footnotes on sources. Its like a rumor passed from hallway to hallway. Many studies do show that many factors have a huge effect on red fox mortality- rabies, distemper, mange and predators. Several studies list raptors as maybe being the top predator. In addition- fox need a little bit more specilized habitat- the reduction of set aside acres and the intense farming practices of today have eliminated much of the traditional territory for fox- jthe fields are just too open. But coyotes thrive in this type of situation.
So my question is this- are coyotes deplacing red fox- as an advancing army- taking territory acre by acre, mile by mile?
If a healthy red fox populations exists- and if coyotes are present- within a few years will the coyotes have displaced the fox- except for isolated pockets near heavy cover?
Or, if suitable habitat exists for both, both will somewhat co-exist? That true takeover of regions by yotes is when conditions dictate low or absent fox populations- in other words a void is created- and at that point the coyotes take over the space?
Where I live in SE Minnesota, we have always had fox. Up north, they have always had coyotes, or "brush wolves". Starting in the 60s, through the early 80s- we had both major land use changes taking place- on many levels- farming techniques, expanding subburbs, set asides, wetland use- and a fur boom like perhaps no other. Add in the other factors- and we are back to the question- the chicken or the egg?
Please, while I value your opinion, I have heard and listened to all sides. As Joe Friday would say I just need the facts.
Is there definitive proof one way or the other on this issue?
Thank you.....trappnman
------------------
Trappnman--The answer to your question is "Yes", but more by township after township rather than mile by mile. The coyotes are the reason that foxes (at least red foxes) are declining in many areas.
We don't see much direct contact between the 2 species, because most of the "war games" occur at night. Both species are extremely nocturnal, of course. Additionally, from what we saw most of the interactions are for space (e.g. territorial imperative or something like that). What generally happens is that the coyotes move in and set up a territory, and the foxes have a decision to make--get out or get killed. We suspect most of the resident foxes leave; however, we don't know this for sure. However, we don't see many dead foxes laying around the country; we do see dead red fox pups at dens, however. The higher the coyote density gets the fewer red foxes will be around, but there will always be a few that find a small spot that none of the coyotes want.
Re: management, the only way to reverse this is that the coyotes have to die. They can die from fur harvesters (moderately expensive, but the expense is borne by private business), government intervention (very expensive, and cost is borne by taxpayers), or by wolves (very inexpensive, but politically a hand grenade with the pin pulled). The only other choice is a major epizootic (e.g. mange), but this will likely affect a bunch of species. Other than that there are no other options.
Re: habitat; we never saw habitat have any affect whatsoever on densities of either species. We saw fox populations of equivalent densities in the early 70's on land that was 80% cultivate and on land that was only 20% cultivated. Additionally, in the 90's we saw equivalent coyote populations on land that was 100% rangeland, and on land that was at least 50% cultivated. I have seen some really high red fox populations in sw ND where the habitat is virtually all rangeland with lots of sage brush flats, dry washes and wooded draws--the country looks about like a Marlboro advertisement.
Bottom line is whichever species is the biggest dog in the area will govern the whole show in that area; neither habitat, food, weather, proximity to human populations will have any affect. Each canid species likes each other fairly well, but it all ends there; they all hate the next species either larger or smaller. Of course, only the largest one can do anything about it. I realize that is hard to believe, but we simply don't have any data to the contrary; I don't know of anyone else that does either.
ok, but how did all of this happen? At least in the west it was related to political changes re: predators and their management. For example, in 1972 there was a ban on the use of toxicants for coyote control and a ban on aerial hunting of all species in the same year. Immediately, part of the annual mortality pressure on coyotes and red fox was removed, and the populations started putting money in the bank instead of taking it out of the bank so to speak. But then the interspecific competition takes over and the coyotes continue to increase and the red foxes begin to decline. This doesn't happen immediately, but it takes a number of years.
There are only 2 things that affect population size; reproduction and mortality. Dispersal and movement become negligible if we expand the study area large enough to contain all the movement. Further, reproduction is reasonably constant (sort of), but it is much more constant than mortality. Mortality can be affected strongly by pelt prices (e.g. the late 70's), and by politics (govt. removal of coyotes, etc). Thus, if the populations of the larger canid species move out of the red and into the black it is at the expense of the smaller canid species. This makes for some interesting management decisions; kinda like robbing Peter to pay Paul... Steve Allen