Friday, October 27, 2017

Mangy Foxes

Red Fox with Sarcoptic Mange (wikimedia commons by Juan Lacruz)

     Several times a year the topic of mangy foxes comes up. Mostly this is by well-intentioned people who want to interfere. Since I end up explaining so often why that shouldn't be done, I decided to put together a blog article I can refer people to each time it happens. Of course, many people may not read all the way through all this information and there are others who just don't want to listen, but this is my attempt to let people know a few things about this. 
     First of all, people are assuming that what is affecting the animal is mange. You can't visually tell if an animal has mange simply by looking. There area a lot of things that can cause loss of hair and has similar symptoms. Aflatoxicosis, alopecia, dermatophilosis, lice, ringworm, and demodicosis for example 
     Let's also make something clear: it is illegal to treat foxes with medication for mange. Period. This is true in most jurisdictions everywhere, including all of Virginia and Maryland. Here's the Virginia Code for example: 
29.-1-508.1 Use Of Drugs on Vertebrate Wildlife
A.   With out a written authorization from the Director or his designee, it is unlawful to administer any drug to any vertebrate wildlife, except in accordance with a permit issued under the provisions of this title or regulations adopted by the Board. This prohibition shall include, but not be limited to, drugs used for fertility control, disease prevention or treatment, immobilization, or growth stimulation. Nothing in this section shall prohibit the treatment of sick or injured wild animals by licensed veterinarians or permitted wildlife rehabilitators. This section shall not limit employees of agencies of the Commonwealth, the United States, or local animal control officers in the performance of their official duties related to public health, wildlife management, or wildlife removal. For the purposes of this section, the term "drug" means any chemical substance, other than food, that affects the structure or biological function of wild species.
B.   The Department may take possession and dispose of any vertebrate wildlife if it believes that drugs have been administered to such wildlife in violation of this section.
C.   Any person violating this section is guilty of a Class 2 misdemeanor. (2004, c. 171.)
     There are numerous good reasons for this law. Even assuming that the correct dose is known and administered (not giving a correct dose may of course result in additional issues and there may be possible side effects regardless), the most common drug used, Ivermectin, is not meant to be used for treating foxes. Any such use is outside its scope. Wildlife rehabbers have even had their licenses revoked for assisting in such illegal activities as helping others treat wildlife using this medication.
     The usual method it is administered is by hiding it inside the food that is offered to the fox. This then assumes the fox gets all the medication and that other creatures don't consume it. If they do, that may also cause additional problems. For instance, some dog breeds, such as collies, can be sickened and even die if they consume Ivermectin. Since it hasn't been tested and is therefore not approved for use on other wildlife, how it affects them is not always known. For example, it will also kill certain species of turtles. Now you may say that turtles don't eat such foods (and you'd be wrong), but also don't forget that the medication can get into the environment through fox feces and urine and perhaps into the water ways. Such are just some of the unintended consequences that are possible. 
     But there's lot more to this. For instance, sarcoptic mange (the most common form of mange, caused by a mite) is one of the only population controls for red foxes. Red foxes by the way, are not native to the DC area, having for the most part moved in to the region, with a small amount of English red fox thrown in from attempts to introduce them for hunting purposes. So they're not supposed to be here. Our native fox is the Grey Fox, which is now severely declined in our area, with some thinking this may also be partially to blame due to competition from the naturalized red fox. Here's more on red foxes from a previous Capital Naturalist Blog:
     Sarcoptic mange affects red fox disproportionately from other creatures, including other canines. Grey Foxes for instance are much less likely to be affected, as are coyotes and dogs, though they can be, as can very rarely even humans. My own dog for instance was affected by mange, picked up from a mangy fox that was being attracted to my yard thanks to a neighbor unwisely feeding it, and then later I found out, also treating it with Ivermectin. By the way, feeding such creatures not only concentrates them and thus allows for easier disease transmission, but may cause them to lose their fear of man and lead to other confrontations or misunderstandings. By the way, red foxes who have had mange are also more likely to get it again, as the medication does not give immunity. It may just be postponing the inevitable.
     But let's say that a red fox is treated and the mange goes away (though perhaps just temporarily). By choosing to try and help this predator, you affect other wildlife. You affect the prey base and the other predators who now have to compete with a predator who isn't even supposed to be here in the first place and has been given an unfair advantage by being fed. Many of these other predators themselves are declining in numbers. The red fox eats their prey (and they eat more than just rodents) and may even prey on them as well. This can include hawks, owls, shrews, snakes, weasels, bobcats, and so many more. Since in many places we have very large populations (too many?) of red foxes already, their numbers can really impact native wildlife.
     This not only means ground nesting birds, but of course rodents and such small creatures as rabbits. When fox numbers decline, their numbers expand, feeding other small predators and helping these small creatures themselves. But red foxes also eat fruits and other plant matter as well, directly competing with herbivores and other omnivores. So its not just quail, waterfowl and other ground nesting birds, but also raccoons and possums among so many others. By choosing to help one charismatic nonnative predator like a red fox, you have countless effects on so many others.
     While it may help you feel good, in the end you did not do nature a favor by interfering. The difference you actually made is often a negative one to other native wildlife, even if the things affected are not as charismatic or as easily noticed. So nature can be cruel, but its more important to think about the native natural community rather than an abundant and charismatic individual. Letting nature take its course is a wiser thing for the ecology and other wildlife. Sorry to be a downer, but thinking of the larger implications and doing so in a balanced and non-emotional way is how we should make wildlife decisions. If nothing else, please follow the law, as it is in place for good reasons. 


  1. I hope all your readers listed and follow this caveat! Your articles are always valuable. This one should be labeled "essential reading." Thank you for all you have given us.

  2. given their integration and long history here, is it really accurate to call them "non-native..." - are you familiar with the research that links healthy red fox populations and lower incidence of lyme disease?

    and coyotes now seem to be making inroads in Fairfax County

    1. Interesting. I had to look up articles about red foxes and lower Lyme disease rates. Here's one in particular:

  3. Excellent article! I will enjoy following your blog.