Science without context

[DeerCamp]

I recently watched a deer podcast online, and they were discussing how weather impacts deer movements. GPS collar studies have brought some much needed science to deer-isms. I got a healthy dose of these while hunting with my old school pops a few weeks ago in Oklahoma.

But in this podcast I heard the host talking about how the moon, wind,etc don't affect deer movements, etc. AND then I heard him repeat the adage that research has found that TEMPERATURE doesn't affect deer movements. I chuckled. Oh boy, here we go.

Science needs context. A couple years ago when the Penn State study came out claiming this, I read the entire publication and looked at the data. The problem was obvious.

The researchers were only using October data. And this oft repeated myth that temperature doesn't affect deer movement is largely based on this study.

For context, I was involved in some deer research when I was in college, and ironically, most of the people that were doing the study were not hunters at all.

So I emailed the researcher. I explained to them my concerns. That in October, a deer is in much different physiological condition than in November. First and foremost, their winter coat is still coming in. Secondly, the cold weather that happens in November is generally much colder, and lasts longer. This drives deer (with ruminant stomachs) to eat more and more often, because digestion is an important key to temperature regulation in ruminants.

He explained that they used October data because November data with the rut was too erratic. But guess what - November is when most people hunt!

20 years of hunting and 15 years of trail cams have 100% confirmed to me that on average, cold days are better to hunt than hot days. It's not even up for discussion if you have spent time in the woods. Sure, you can kill a buck on a warm day. But you can kill 3 bucks to every 1 of those on a good cold day after a front.

And don't get me wrong, I'm not bashing these researchers. They ARE doing good science, and their intentions are noble. But they need context.

Weather absolutely, 100%, without question, impacts deer movement. More specifically temperature and wind.

So I invited him to come hunt with me. I would pick 3 warm days for him to hunt, and I would hunt 3 cold days and see who sees more deer. He graciously declined.

Considering the context, I don't blame him.

 

[TheLBLman]

To put things in better context, the data needs to be dated, and continuous, not just in October, or any other month or two . . . . . . continuous.

In late December in TN, it is often the "moderate" to warmer temperature days having the better deer movement. When it gets too cold, they just stay bedded in the pines. Also, in late winter, afternoons can be notably better than mornings, while I find just the opposite in November.

To complicate things further, every year there can be some very different factors, such as lots of acorns, no acorns, crops planted or not, ongoing changes in habitat, and then the deer having seasonal ranges within each year, but not exactly matching the prior year.

The more we learn about deer movements, the more we realize we don't know.

 

[Popcorn]

I agree ! WY too many variables for them to make such a broad declaration over a narrow research window.

 

[gatodoc]

One thing I've noticed. When observing fields while driving, be it hot or cold mid day of at morn or dusk, whe I see deer out in one area, I see deer out 5 mi away.

whatever the reaso, when some move at a time all in the area are moving. AMAZING

 

[UTGrad]

Men can't get pregnant.

 

[Hillbilly Hunter]

The thing about Science and Data is, it can be made to show just about whatever you want it to. Alot depends on how it is collected and the motive behind the ones collecting it.

 

[fairchaser]

If we will just use some common sense, we'd know that there are always multiple factors in deer movement. We could probably name 10 right off the top of our head. Singling out one is rediiculous.

Temperature is one factor but it's also relative to the time of year. Cold will make deer move more to a point unless it's too cold. If they lose too much heat while eating, they may not move. That's natures way of survival.

 

[AT Hiker]

I just wanna know why moon phase is relevant during the elk rut but apparently doesn't apply to whitetails?

 

[Chickenrig]

I recently watched a deer podcast online, and they were discussing how weather impacts deer movements. GPS collar studies have brought some much needed science to deer-isms. I got a healthy dose of these while hunting with my old school pops a few weeks ago in Oklahoma.

But in this podcast I heard the host talking about how the moon, wind,etc don't affect deer movements, etc. AND then I heard him repeat the adage that research has found that TEMPERATURE doesn't affect deer movements. I chuckled. Oh boy, here we go.

Science needs context. A couple years ago when the Penn State study came out claiming this, I read the entire publication and looked at the data. The problem was obvious.

The researchers were only using October data. And this oft repeated myth that temperature doesn't affect deer movement is largely based on this study.

For context, I was involved in some deer research when I was in college, and ironically, most of the people that were doing the study were not hunters at all.

So I emailed the researcher. I explained to them my concerns. That in October, a deer is in much different physiological condition than in November. First and foremost, their winter coat is still coming in. Secondly, the cold weather that happens in November is generally much colder, and lasts longer. This drives deer (with ruminant stomachs) to eat more and more often, because digestion is an important key to temperature regulation in ruminants.

He explained that they used October data because November data with the rut was too erratic. But guess what - November is when most people hunt!

20 years of hunting and 15 years of trail cams have 100% confirmed to me that on average, cold days are better to hunt than hot days. It's not even up for discussion if you have spent time in the woods. Sure, you can kill a buck on a warm day. But you can kill 3 bucks to every 1 of those on a good cold day after a front.

And don't get me wrong, I'm not bashing these researchers. They ARE doing good science, and their intentions are noble. But they need context.

Weather absolutely, 100%, without question, impacts deer movement. More specifically temperature and wind.

So I invited him to come hunt with me. I would pick 3 warm days for him to hunt, and I would hunt 3 cold days and see who sees more deer. He graciously declined.

Considering the context, I don't blame him.

Oh yeah
There is good science and there is bad science. You can make anything look like how you want the outcome to look !!! Just remember ……4 out of 5 dentists recomend Crest

 

[DaveTN]

It's not just science; its anything. People have something they want the data to show, so they make it show that. We see it here all the time. Especially in political discussions.

 

[MickThompson]

Keep in mind it isn't like what movies would have you believe. GPS collars generally give hourly updates because of battery life. Radio telemetry is maybe twice daily, as that requires someone to collect and they are cycling through all their critters.

 

[BSK]

If we will just use some common sense, we'd know that there are always multiple factors in deer movement. We could probably name 10 right off the top of our head. Singling out one is rediiculous.

Temperature is one factor but it's also relative to the time of year. Cold will make deer move more to a point unless it's too cold. If they lose too much heat while eating, they may not move. That's natures way of survival.

And that's the key. What influences deer movement is so highly multivariant. Lots of things influence deer movement and they are all interacting at the same time. Trying to pull out one influence over the others is virtually impossible.

Another key factor is how is "movement" being defined? In a study's criteria, how is movement defined as movement?

 

[BSK]

I recently watched a deer podcast online, and they were discussing how weather impacts deer movements. GPS collar studies have brought some much needed science to deer-isms. I got a healthy dose of these while hunting with my old school pops a few weeks ago in Oklahoma.

But in this podcast I heard the host talking about how the moon, wind,etc don't affect deer movements, etc. AND then I heard him repeat the adage that research has found that TEMPERATURE doesn't affect deer movements. I chuckled. Oh boy, here we go.

As with any single influence, there is more going on than just that single influence. The rut, wind, pressure changes, precipitation, etc. But looking at hunter observations on a single property over 35 years, temperature plays a role. The below graph is hunter collected buck sighting rates for morning hunts in November, analyzed degree by degree and with the statistical trend. The data makes it clear that good hunts can occur in warm weather and bad hunts can occur in colder weather, but the statistical trend (black line) shows that on average hunters see bucks twice as often when morning lows are cold versus morning lows that are very warm.

 

[TheLBLman]

Another key factor is how is "movement" being defined? In a study's criteria, how is movement defined as movement?

"Movement" can be in small circles around a single productive oak tree;
Movement can be a deer standing up from it's bed, taking two steps to urinate,
then bedding back down;
Movement can be linear and long distance.

"Movement" itself without more description & context means very little.

During the November rut (when it occurs most places in TN), there was great LINEAR movement of bucks, and more linear movement of females than most months. Bucks would commonly travel over a mile in a single direction daily, even multiple times in a 24-hr period. Old females would also travel considerable linear distances at times, looking for Mr. Right.

But now, post-rut, same areas on December 6, near zero linear movement. Some of the oaks are still dropping acorns, and many the deer are simply bedding & feeding a full 24-hr period within 100 yds of those particular oaks. This is very low-probability deer hunting for most hunters.

 

[DeerCamp]

"Movement" can be in small circles around a single productive oak tree;
Movement can be a deer standing up from it's bed, taking two steps to urinate,
then bedding back down;
Movement can be linear and long distance.

"Movement" itself without more description & context means very little.

During the November rut (when it occurs most places in TN), there was great LINEAR movement of bucks, and more linear movement of females than most months. Bucks would commonly travel over a mile in a single direction daily, even multiple times in a 24-hr period. Old females would also travel considerable linear distances at times, looking for Mr. Right.

But now, post-rut, same areas on December 6, near zero linear movement. Some of the oaks are still dropping acorns, and many the deer are simply bedding & feeding a full 24-hr period within 100 yds of those particular oaks. This is very low-probability deer hunting for most hunters.

100%. And there's that context.

I don't need science to tell me that deer observations increase during cold weather. It's a fact.

Then people read a headline and represent the facts incorrectly and we have to remind them that context is needed.

 

[TheLBLman]

I don't need science to tell me that deer observations increase during cold weather. It's a fact.

Ah, define "cold" weather
"Cold" also must be put into context.
If it gets too cold, deer observations will decrease. It's a fact

 

[DeerCamp]

As with any single influence, there is more going on than just that single influence. The rut, wind, pressure changes, precipitation, etc. But looking at hunter observations on a single property over 35 years, temperature plays a role. The below graph is hunter collected buck sighting rates for morning hunts in November, analyzed degree by degree and with the statistical trend. The data makes it clear that good hunts can occur in warm weather and bad hunts can occur in colder weather, but the statistical trend (black line) shows that on average hunters see bucks twice as often when morning lows are cold versus morning lows that are very warm.

I really wish you would reach out to Dr. Deifenbach at Penn State and try to talk some sense into him. He is unfortunately misinforming a lot of people with good data that is being taken out of context.

Duane Diefenbach, Ph.D.

ecosystems.psu.edu

 

[megalomaniac]

The study author probably isn't a real hunter.

 

[Ski]

If it gets too cold, deer observations will decrease.

That's right. Just like us they will hunker down during hard temp drops. Then there's a flurry of movement as the front moves out and temp stabilizes again.

I'm not bothered by the misinformation directed at hunters. I suppose if I were young or new hunter I'd find it frustrating, but then again maybe not. I've always considered new information regardless of source and weighed it against my own experience to decide if it's valid or not.

 

[woodsman04]

To put things in better context, the data needs to be dated, and continuous, not just in October, or any other month or two . . . . . . continuous.

In late December in TN, it is often the "moderate" to warmer temperature days having the better deer movement. When it gets too cold, they just stay bedded in the pines. Also, in late winter, afternoons can be notably better than mornings, while I find just the opposite in November.

To complicate things further, every year there can be some very different factors, such as lots of acorns, no acorns, crops planted or not, ongoing changes in habitat, and then the deer having seasonal ranges within each year, but not exactly matching the prior year.

The more we learn about deer movements, the more we realize we don't know.

I agree with all of this.
Late season, late December and January, it needs to be seasonal temperatures. Afternoon food plot or ag field hunting is usually more productive. I think they feed all night long.