Subject: [Tweeters] Re: Red Fox Date: Jul 20 14:21:51 2009 From: Kevin Purcell - kevinpurcell at pobox.com
On Jul 20, 2009, at 12:05 AM, Kelly McAllister wrote:
> I think it will be pretty hard to find anyone, in an official > capacity, who will care to receive sightings of Red Fox in > Washington. Keith Aubry of the U.S. Forest Service is likely one > exception though.
Keith Aubry wrote a masters thesis at the UW in 1983 on the distribution of the Red Fox in Washington. And of course his masters raised some important issues (like no one had really though about the distribution of "lowland" Red Foxes because they already had multiple introductions). He later published a paper in Northwest Science that fortunately has been scanned an put up on the web. It makes for an interesting read (if for no other reason than using hunting and museum data to build a picture a historical county range description).
Keith Aubry, "The Recent History and Present Distribution of the Red Fox in Washington", Northwest Science, vol 58, no. 1, 1984
> Personally, I believe that sightings of animals at mid-elevations of > the Cascade Mountains (500-2,500 feet) are very important to get on > the record. The introduced Red Fox seems to be relatively well > established, near sea level, in western Washington. I've heard of > many sightings in areas within several miles of marine shorelines.
People might also find this GAP Analysis Predicted Distribution Map from UW helpful in visualizing where you *might* find Red Foxes.
> Then, there are the apparently native animals of the subalpine > parkland habitat in the Cascade Mountains. I have seen little or > nothing to suggest that the introduced foxes range into the occupied > habitat of the native foxes. I don't think there's much question > that the animals in the high country of the Cascades are isolated > from the introduced stock.Certainly, the predominance of the silver > phase in these animals is consistent with the native condition. > > The paper that Kevin Purcell linked to suggests that red fox are > incredibly adaptable. If so, it is difficult to explain the apparent > long-term isolation of these two fox populations despite the many > decades of opportunity for the introduced fox to spread and come > into contact with the native form. As far as I can tell, the non- > native foxes simply haven't shown that much resilience and > adaptability in Washington. They seem to occupy a fairly specific > niche. > > Kelly McAllister > Olympia, Washington
So for those interested in a more detailed look at the "lowland" Red Fox versus the "mountain" Red Fox the Aubry paper is worth a read. There have been multiple introductions of Red Fox in WA so non-native introduction is not just a matter of diffusion of Red Foxes into this area from the East (through habitat poor for them) but deliberate introductions starting at the beginning of the 20th century (for hunting) and there have been escapes of farmed "Silver" and other color morphs of the Red Fox since then too. All color phases have been farmed here.
I think there is a worthwhile research project in doing DNA work on "native" and non-native foxes. Do they intergrade or are they isolated from the lowland Red Fox? Are they native? How do they compare to Boreal Red Foxes (can you guarantee those are "native"). If they are isolated what is their current range? How large is the population? Why are they isolated from breeding (physical separation of their habitat or some other preference)?
Or back to Aubry's original question: "what is the range of the "lowland" Red Fox?"
Of course, if they're the same species they should breed where habitat overlaps especially in the Northern Cascades where Steven's Pass and Snoqualmie pass would seem to connect lowland King Co. and highland areas in Chelan and Kittitas counties together along with habitat between them. Perhaps even the North Cascades Highway (though there is a little gaps there). And in the "Southern" Cascades where lowland foxed in Lewis county could meet with highland foxes in Cowlitz and Yakima counties. Are there physical barriers that prevent them interbreeding?
There is some interesting work to be done here. :-) -- Kevin Purcell kevinpurcell at pobox.com