Bird of the Month:
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| "Tracking is seeing. Seeing is done with the mind." |
Tracking Problem
appropriate to their constantly changing habitat.
The only predator I know of that, under natural conditions, sometimes wipes out its food supply is the
human one. An instinctive intelligence, honed by millennia of ruthless selection, seems to have made
dumb animals somewhat wiser than ourselves
The only predator I know of that, under natural conditions, sometimes wipes out its food supply is the
human one. An instinctive intelligence, honed by millennia of ruthless selection, seems to have made
dumb animals somewhat wiser than ourselves
Raven
Similar to our common crow, the
raven is larger, has a
disproportionately larger beak and a
rounded or wedge-shaped tail. In the
eastern U.S. this bird was regarded
as "rare and local in the
Appalachians" until the last few
decades. More recently it has greatly
expanded its range and now occurs
sparingly even in the Boston
suburbs. Renowned for its
intelligence, resourcefulness and
sense of play, the raven is with us all
winter, scavenging on hunter
leavings and winter-killed carcasses.
(The astute tracker can often locate
these scavenging sites by paying
attention to raven calls.) As spring
approaches these birds get very
active, putting on aerial displays to
advertise their fitness to potential
mates, all the time calling with an
amazing variety of vocalizations,
none of which, to my ear at least,
remotely resemble "Nevermore".
Similar to our common crow, the
raven is larger, has a
disproportionately larger beak and a
rounded or wedge-shaped tail. In the
eastern U.S. this bird was regarded
as "rare and local in the
Appalachians" until the last few
decades. More recently it has greatly
expanded its range and now occurs
sparingly even in the Boston
suburbs. Renowned for its
intelligence, resourcefulness and
sense of play, the raven is with us all
winter, scavenging on hunter
leavings and winter-killed carcasses.
(The astute tracker can often locate
these scavenging sites by paying
attention to raven calls.) As spring
approaches these birds get very
active, putting on aerial displays to
advertise their fitness to potential
mates, all the time calling with an
amazing variety of vocalizations,
none of which, to my ear at least,
remotely resemble "Nevermore".
How predation works:
As trackers we should want to know more about the animal whose sign we encounter in the field than
simply its identity. The tracks, trails and sign can tell a lengthy and interesting story, answering the
questions: What was the animal doing? Why was it here? To develop some answers to these and
other questions, we should know how basic predation works.
As trackers we should want to know more about the animal whose sign we encounter in the field than
simply its identity. The tracks, trails and sign can tell a lengthy and interesting story, answering the
questions: What was the animal doing? Why was it here? To develop some answers to these and
other questions, we should know how basic predation works.
A few years ago I heard a tracker announce at a meeting that once fishers arrive in an area, they
wipe the porcupines out. Another similar notion was presented by a coyote fancier who gave a
presentation, complete with slides, on how the wolves that have been reintroduced to Yellowstone
were "wiping out the coyotes". And a third came from an old hunter who declared to me that fishers
were the reason for the snowshoe hare decline.
wipe the porcupines out. Another similar notion was presented by a coyote fancier who gave a
presentation, complete with slides, on how the wolves that have been reintroduced to Yellowstone
were "wiping out the coyotes". And a third came from an old hunter who declared to me that fishers
were the reason for the snowshoe hare decline.
Prey animals develop a hierarchy among
themselves. The fittest and strongest dominate the
less fit. In the case of porcupines, there are only so
many places in a forest to hide one's vulnerable
face from bobcats, fishers, coyotes and foxes. The
fittest porcupines appropriate places, such as rock
crevices or hollow logs, for themselves, driving off
the subordinate members of their species. These
sub-dominant animals, then, represent a vulnerable
surplus. It is these creatures on which the available
predators concentrate. Once this surplus has been
taken off, predators tend to find the remaining
dominant prey animals too difficult or dangerous to
attack. So they abandon the hunt for porcupines
and turn instead to whatever other prey species
happens to be enjoying a surplus at the moment.
Thus it is an error to insist that fishers wipe out
porcupines in an area. Instead of eliminating their
food supply, they simply farm it, leaving the
dominant and dangerous prey animals to procreate
the next generation of the predator's food supply.
As it turns out, after an initial period in which
Yellowstone's wolves did in fact reduce the coyote
population, the remaining coyotes learned to live
along the seams of wolf pack territories, which the
wolves avoided for fear of violent interaction with
adjacent packs. Not only did the coyotes survive
themselves. The fittest and strongest dominate the
less fit. In the case of porcupines, there are only so
many places in a forest to hide one's vulnerable
face from bobcats, fishers, coyotes and foxes. The
fittest porcupines appropriate places, such as rock
crevices or hollow logs, for themselves, driving off
the subordinate members of their species. These
sub-dominant animals, then, represent a vulnerable
surplus. It is these creatures on which the available
predators concentrate. Once this surplus has been
taken off, predators tend to find the remaining
dominant prey animals too difficult or dangerous to
attack. So they abandon the hunt for porcupines
and turn instead to whatever other prey species
happens to be enjoying a surplus at the moment.
Thus it is an error to insist that fishers wipe out
porcupines in an area. Instead of eliminating their
food supply, they simply farm it, leaving the
dominant and dangerous prey animals to procreate
the next generation of the predator's food supply.
As it turns out, after an initial period in which
Yellowstone's wolves did in fact reduce the coyote
population, the remaining coyotes learned to live
along the seams of wolf pack territories, which the
wolves avoided for fear of violent interaction with
adjacent packs. Not only did the coyotes survive
A dominant porcupine gets the best places to hide its
vulnerable face from predators.
vulnerable face from predators.
As for the fishers eradicating the snowshoe
hares, drops in the populations of this lagomorph
are cyclical, caused not be fishers but by the
development every 7-10 years of anti-browsing
toxins in the hares' staple browse plants. As the
hares weaken from starvation, they become easy
prey for any predator in the area and as a result
the fur of these prey animals shows up
disproportionately in the scats or pellets of any
predator skilled at capturing them, such as
fishers, but also bobcats, coyotes, foxes, hawks
and owls.
Equilibrium is unnatural. Any species of wild
animal in order to remain truly wild must go
through periods of high population followed by
periods of decline. The lower end of the sine
curve is critical to the ultimate health of the
along these borders, they actually prospered. The wolves, unlike the coyotes, were able to bring
down elk, the remains of which became available to the surviving coyotes as scavenge.
down elk, the remains of which became available to the surviving coyotes as scavenge.
An owl pellet shows the mandible of a small rodent.
species. It is during periods of hardship that the genetic fitness of the species is tested and
inappropriate genetic material is weeded out. Once this testing period is finished, the remaining
members are then fit to procreate the rising generations of new offspring with characteristics
inappropriate genetic material is weeded out. Once this testing period is finished, the remaining
members are then fit to procreate the rising generations of new offspring with characteristics
What happened here?
The scene is a rarely mowed field in west central Massachusetts
covered with 4" of snow over matted grass.
In the top photo an animal has moved out into the field, leaving direct
registrations 15 inches apart.
At one point in its progress it produced the disturbances in the
lower-left photo. A close-up of which is shown in the bottom-right frame.
1. Identify the animal.
2. Determine the gait of this animal in the top photo.
3. What is the cause of the disturbances in the middle photo?
4. What prey is the animal seeking?
5. Relate the body parts of the animal to the evidence in the bottom
right frame.
The solution appears on another page on this website.
The scene is a rarely mowed field in west central Massachusetts
covered with 4" of snow over matted grass.
In the top photo an animal has moved out into the field, leaving direct
registrations 15 inches apart.
At one point in its progress it produced the disturbances in the
lower-left photo. A close-up of which is shown in the bottom-right frame.
1. Identify the animal.
2. Determine the gait of this animal in the top photo.
3. What is the cause of the disturbances in the middle photo?
4. What prey is the animal seeking?
5. Relate the body parts of the animal to the evidence in the bottom
right frame.
The solution appears on another page on this website.