Lynx

[Sully]

From: The Lynx and us

"Researchers then recorded the remains of animals that lynx had killed and signs of any scavengers. As expected, over 90% of the 617 individual animals killed by the lynx were roe deer and chamois, and more than half the carcasses had been scavenged by foxes. Furthermore, the third most commonly killed species was fox, with 37 animals killed. This compared to one each of badger, pine marten, domestic cat and wildcat, representing very low levels of predation on these smaller carnivores. Adult female lynx were, on average, killing 1.5 foxes annually, while adult males killed 2.3. Subadult lynx, which were presumably tackling big prey such as roe deer and chamois less often, killed 6.1 foxes, while a mother with kittens would kill on average 13.3 foxes annually. 

Taken together this gives a weighted average of 4.8 foxes killed per lynx each year. However, these losses are not thought to be significant to the Swiss fox population, which has increased at much the same time as the lynx population over the past few decades. This suggests that in the relatively productive landscapes found in more southern parts of Europe, foxes are just too numerous to be controlled by lynx.

The picture in large parts of northern Europe, however, appears to be quite
different. Here environmental productivity is lower, partly because of the
colder climate and partly because agricultural landscapes, which favour foxes
by providing them with lots of feeding opportunities, are much less extensive
than further south.
It might first appear that foxes actually benefited from the spread of lynx
across central Sweden in the mid 1990s. By routinely killing roe deer all year
round, lynx provide foxes with carcasses to scavenge. Compared to before the
lynx’s reappearance, much more of the fox’s diet is now made up of roe deer,
despite lower roe deer densities than before. Venison has become the single
most important food for them, forming around 50% of their diet in winter and
38% in summer85.
In fact foxes have been eating twice as much roe venison in recent mild winters
than they did in the particularly harsh winter of 1976-77 when there had been
many roe deer deaths, but when lynx were absent. This food bonanza, however,
has not led to an increase in the fox population. In fact, foxes have declined
over the timescale of the lynx’s recolonisation and population growth, with
scientists arguing there is no plausible explanation other than killing by lynx.

Studies from Norway and Sweden have shown that lynx predation of foxes
could be at levels which are significant for the fox population. In one study
lynx caused half of the mortality in radio-tracked foxes, which were mostly
breeding age adults in good condition84. Lynx don’t always eat foxes when
they’ve killed them, with another study from central Norway finding that more
than a third of foxes killed by lynx had been left uneaten86. In fact a single lynx
had killed three foxes consecutively on the same track, without eating any of
them. This waste of carcasses is unusual for lynx and suggests some lynx kill
foxes to remove a scavenger, but perhaps don’t eat them because of the risk
of contracting disease." Reply