Senses & the Wind
There’s no recording of this volume, so your phone reads it out, section by section.
Nose, ears, eyes, in that order. How a deer reads you, and how you read the wind so it never gets the chance.
Nose first
A deer reads you in a fixed order: nose, then ears, then eyes. Get that order into your head and most of field craft explains itself. You can stand still and beat its eyes. You can walk softly and beat its ears. You cannot beat its nose. You can only keep yourself out of the air it's breathing.
Smell is probably a deer's main sense. British deer managers reckon a deer can pick up human scent over many hundreds of metres, and nobody who has been winded at long range would argue. Hard numbers are thin, but the anatomy tells the story: when the scent-sensing lining of the nose was measured in roe deer, another European deer, it covered about 90 square centimetres, against about 10 in a person.
What a nose can't do well is say exactly where a smell is coming from. As the NSW hunter education handbook puts it, scent tells the animal danger is about, not precisely where. That's no comfort. A deer that knows danger is about leaves.
Your scent comes off your skin, your breath and your clothes, and the moving air carries it away from you in a plume. Close to you it's narrow and strong. Further downwind it spreads and thins into a cone, wandering as the breeze wanders. Anywhere inside that cone, a deer can have you. Outside it, its nose knows nothing about you. The textbook cone is a straight wedge. Real air is messier, and the simulator below shows how.
Try this: walk straight up towards her with the wind in your face, the textbook approach. Then turn the wind so it runs along the ridge instead of over it, and try again.
What the dots are
A rough picture of the idea, not a forecast for any real hill. The wedge is what most people imagine. The dots wander when the breeze is fluky, and in the lee of the ridge they run back uphill, lift at the crest and come round again, filling the pocket under the ridge, because that's what air does when it tumbles over a crest. Chapter II explains why.
Fig. 2The sight and hearing figures come from studies of North American white-tailed deer, the colour cones from fallow, and the nose from roe deer.
Lore
In the rut, a buck that sniffs a doe's urine curls his top lip back and lifts his nose with a look of faint disgust. That face is the flehmen response. It pushes the scent towards a second smelling organ in the roof of his mouth, the vomeronasal organ, which tells him whether she's coming into season.
Reading the wind
The NSW hunter education handbook keeps coming back to one rule: keep the wind in your face, because your scent will alert the animal long before you see it. Easy to say. The trouble is that you can't see the wind, so you have to give it something to carry, and you have to check it where you are, at the height you are, every time the country changes.
A puffer bottle
A squeeze bottle of fine, scent-free powder. One puff at chest height or lower and the little cloud drifts off the way your scent will. Cheap, quick, and the one to carry.
Thistledown
The fluff off a thistle head or a dandelion clock. It floats for tens of metres and shows you what the air does further on: lifting, curling, swinging back on itself.
Your own face
A wet finger, the breeze on your cheek and ears, grass heads nodding. Fine for direction in a decent breeze. Hopeless in the light, shifty air that matters most.
A flag on the homestead pole, the treetops, the forecast on your phone: they all tell you about the wind somewhere else. The flag is six metres up, where the air runs smooth. Down in the grass, where your scent travels and the deer feed, the same breeze bends around trees, pours down gullies and stalls in hollows, and it can run a different way entirely.
And a flag needs a proper breeze to lift at all. It hangs limp in exactly the light, wandering air that carries scent in every direction. Powder and thistledown show you that air. A flag doesn't.
Wind behaves a lot like water. It speeds up over a crest, then tumbles down the far side, the lee, and peels away from the ground. Behind it the air spins into an eddy, and down at ground level that eddy can run backwards, back up the slope towards the ridge.
That's how you get caught. You come up from below with the wind in your face, feeling clever, and the eddy under the crest carries your scent uphill to the very animal you're hiding from. Gullies and creek lines play their own game too, steering the breeze along them whatever it's doing on the tops.
- Check the wind at ground level, where you're standingNot the treetops, not the flag, not the app.
- Plan to come in from downwind, or straight across itA steady crosswind is workable. A wind at your back isn't.
- Check again whenever the ground changesA gully, a saddle, a creek line, the edge of the timber.
- Watch the powder for a while, not a momentA breeze that swings back every half minute is a fluky one.
- If it turns on you, back outThe deer will be there tomorrow. Winded, it won't be.
After dark
Breezes often die away after dark as the ground cools, and still air on any slope drains downhill. So when you climb off the ute to walk in on a deer at night, one below you on a slope can have your scent with no breeze you can feel, and one above you probably can't. Check with powder anyway. The torch makes the drift easy to see.
Thermals
On a still day the air on a hillside still moves, and it moves to a timetable. When the sun warms a slope, the air against the ground warms with it, gets lighter and creeps uphill. Meteorologists call that an anabatic wind. When the sun leaves the slope, the ground cools fast and chills the air on it, and that heavier air slides downhill and pools in the gullies. That one is katabatic. Hunters call both of them thermals.
Your scent goes where the air goes. So on a slope with little or no wind, the rule is simple. When the air is sliding down, come at the deer from below. When it's rising, come from above. And when it's changing over, sit tight, because for a while it goes everywhere.
The change doesn't happen everywhere at once. A slope facing east gets the sun first and turns in the morning while the west-facing slope across the gully is still draining. In the afternoon it runs the other way. A real wind overrides the lot, so check with powder before you trust the timetable.
Everything drains
Cold, heavy air slides down both slopes and pools in the gully floor. Your scent goes downhill with it. Come at a deer on the slope from below.
The sunny slope turns
The sun lands on the east-facing slope first and its air starts to stall and swing. The shaded slope across the gully is still draining. On the turning slope, sit tight until it settles.
Rising on the east face
The east-facing slope is climbing now, so get above anything on it. The west-facing slope is only just turning.
Both slopes climb
Sun on both faces, air rising on both. Come from above. On a hot day this is when the deer are bedded anyway.
Still rising
Air keeps climbing while the sun is on the slope. The west-facing slope is in full sun and running strongest.
The shady slope turns
The east-facing slope falls into shade first and its air stalls, swings and starts to drain. Expect a few minutes of air going every direction.
Down again
The east-facing slope is draining. The west-facing slope turns as the last sun leaves it. Evening is a from-below job.
Pooling
Cold air drains off every slope and settles in the low ground, which is why the gullies are coldest and why your scent gathers there. Spotlighting off the ute on the flats, keep it in mind.
On this trip
Silent Grove's gullies run on the same air as the Southern Alps, just smaller. First light usually means air draining downhill, so the dawn plan is to be below the animals and to climb as the day warms. In the tops the slopes are far bigger, and so is the air moving on them.
Lore
Glider pilots go looking for the same air you're trying to avoid. Sun-warmed slopes push air uphill, and pilots work those faces for lift. What carries a glider up a mountain carries your scent up it too.
The ears
A deer's ears never stop moving. Each one swivels on its own through close to 180 degrees, so one can track you while the other stays on the mob, and between them they cover the whole circle. Deer are good at picking one suspicious sound out of the bush's background noise and turning both ears on it.
Measured in white-tailed deer, hearing runs from about 250 hertz up to 30,000, with the sharpest hearing between about 4,000 and 8,000. You top out around 20,000, and less as you get older. So a deer hears sounds too high-pitched for you to hear at all. The practical lesson is simpler than the numbers: sharp, sudden and unnatural sounds give you away.
The Silent Grove packing list already says it: leave the crinkly rain shell at home, because they hear it well before they see you. Every step in a stiff, hard-faced jacket sounds like someone screwing up a chip packet. Wool and fleece are quiet. If rain's forecast, quiet waterproofs exist, and they're worth the money.
The rest of the list is the same idea. Zips and velcro. Loose cartridges rattling in a pocket. A sling swivel tapping the stock. A car door slammed instead of pushed shut. Voices, even low ones. Boots on dry sticks and loose stone. The bush is full of noise, and deer know which noises belong.
Lore
Fallow does give a single, short alarm bark when they're sure something is wrong. Hear it once and you'll know it for life, and so does every deer within earshot.
The eyes
Deer eyes are built for one job: spotting something moving, in poor light, from almost any direction. Set on the sides of the head, they take in close to 300 degrees without the deer turning its head, going by studies of white-tailed deer. Only about 60 degrees out front are seen by both eyes at once, so judging distance isn't its strong suit, and right behind it sits a blind wedge of about 60 degrees.
A deer's retina is packed with rods, the cells that work in dim light, and has far fewer of the cones that see colour and fine detail than yours does. Behind the retina sits a mirror layer, the tapetum, that bounces light back through for a second go. That's the eyeshine you'll see in the spotlight. Their sharpest vision runs in a horizontal band across the eye, lined up with the horizon, where trouble usually comes from.
About 60° with both eyes
The narrow wedge straight ahead, where a deer judges distance best. A deer that turns to face you square is using it, and has picked you out.
About 120° on each side, one eye
Most of the circle. Superb for catching movement, poor for detail and depth. You can be in plain sight here and still unread, as long as you don't move.
About 60° behind
The only blind patch, and the deer can close it with a turn of the head. Don't count on it. Fallow feed with heads swinging and tails flicking, and the mob covers every angle between them.
Narrower, but deeper
You see roughly two-thirds of the circle a deer does, but about twice its overlap out front. Forward-facing eyes are a hunter's eyes: built for judging distance and detail, not for watching your back. It's why you can pick out a deer's ear flick at a hundred metres, and why it can't easily tell what you are.
You see colour with three kinds of cone. Deer have two. In fallow, measured directly from the retina, one cone peaks in the blue at about 450 to 460 nanometres and the other in the green at about 542. There's no red cone. So deer aren't colour-blind, they're dichromats, much like a person with red-green colour blindness. Blues stand out. Reds, oranges and greens collapse into one muddy family.
Fig. 9Drag across. The deer side is a standard two-cone colour model, plus a guess at a brightened shirt in failing light. It shows which colours a deer can tell apart, not what being a deer is like.
Blaze orange is designed to scream at people. To a deer it probably reads as a dull brown or grey. Victoria's game authority notes that plenty of hunters wear it and still take their deer. What gives you away is your outline and your movement, not the colour of your hat.
Blue is the one to worry about. A deer's most sensitive cone sits in the blue, and trained deer tested in the United States were most sensitive to short, blue wavelengths and least to long, red ones. So blue jeans and a blue jacket stand out. The packing list says dull colours beat bright, and this is why.
Then there's the washing powder. Most laundry detergents carry brighteners that turn invisible ultraviolet into visible blue so your whites look whiter. Deer lenses let through short-wave light that ours filter out, so researchers at the University of Georgia reckon a brightened shirt may glow to a deer at dawn and dusk. No study has yet shown whether it costs hunters animals. Washing your hunting clothes in a powder without brighteners costs you nothing.
Red light, white light
The same biology is behind red spotlight filters. NSW's procedures for shooting deer note that a red filter may reduce the light deer see. Fallow have no red cone, so a red beam looks dim to them, not invisible. White light is better for identifying exactly what's in the beam, and when you're spotlighting, identification comes before everything.
Lore
Deer pupils are horizontal slits. Watch one drop its head to graze and its eyes roll in their sockets to keep those slits level with the ground, so the panoramic strip of vision never tilts. Researchers who filmed it found the same trick in sheep, goats, horses and moose.
Stillness
Here's the catch in all that eyesight. Deer are superb at catching movement and surprisingly poor at making sense of a shape that doesn't move. Freeze and you can become a stump. Shift your weight and you're a person again.
That's why the freeze works, and why it's only half the job. A deer that has caught something odd will stare at it, sometimes for a long time, and fallow pick up movement at great distance. Your outline still counts: a head on the skyline, a pale face, the flash of a scope lens or a watch. Stillness buys you time, not invisibility.
Watch her head. Move while it's down. Freeze the moment it comes up.
Head down, tail flicking
Feeding. Fallow flick their tails almost constantly while they feed, so the tail tells you nothing on its own. The head does. Down means move.
Head up, ears on you
Looking. Freeze, mid-step if you have to, and don't move again until the head goes back down. If she keeps staring, she's not sure. Let her stay that way.
Tail up, then the bark
Alarmed. The tail goes up, a doe barks, and the mob leaves in that bouncing gait fallow use when they're spooked. Your stalk is over. The next one starts now.
- Wind checked at ground level, where you are
- Approach planned from downwind, or across it
- Thermals: which way is the air going on this slope, right now?
- Quiet clothes, nothing in your pockets that rattles
- Nothing blue, nothing freshly brightened
- Move when heads are down, freeze when they come up
- Off the skyline
Nose first, so the wind decides where you walk. Ears second, so you walk quietly. Eyes last, so you walk when she isn't looking. Get the first one wrong and the other two don't matter.