Deer Jumping the String

When I started bowhunting in the late 1970s, I missed more deer than I care to admit to. I was very proficient at the bow range but terrible when it came to real-life shooting opportunities. Because I was typically missing high, I always assumed it was because I was flinching upward right before my shot.

For many bowhunters, missing deer is simply a case of eating humble pie. And many just point to themselves, like I did, as the main source of error. But is this correct?

Luckily for me, and everyone else involved with Bowhunter TV, (now entering its 20th year on Sportsman Channel and Outdoor Channel), we have top-notch cameramen who do a great job of filming our shots and provide us with footage that we can review later back at camp when things go awry. Trust me when I say that being able to watch your “uncertain” arrow frame by frame, and in slow-motion on a TV screen, is priceless!

All that said, the purpose of this column is to educate you on what we have learned over years of viewing deer “ducking the arrow” on video.

A number of years ago, fellow wildlife biologist, Dr. Grant Woods, produced a very informative show on “Growing Deer TV” about this very subject. Woods teamed up with an engineer from Pennsylvania to produce a one-of-a-kind machine — with a sensitive microphone — to see how deer reacted to the sound of a bow being shot. Woods and his buddy shot arrows at 20, 30, and 40 yards, with two compound bows shooting at 258 and 306 fps.

Woods then used the speed of sound to calculate the time between when the bow was shot and when the arrow reached the target at those three distances. Woods and his engineer friend then calculated the time it took the sound of the bow shot to reach the deer for them to start responding. Then Woods used the speed of gravity to determine how fast a deer should drop at the various distances.

In short, Woods learned that bowhunters can get away with bad shots at 20 yards but not 40 yards, because deer have way too much time to react to the sound of the bow going off at the longer distance. In fact, Woods made a graph that showed deer would drop 10-plus inches at 40 yards with the slower bow, and 5-plus inches with the faster bow. At 30 yards, deer dropped 6 inches with the 258-fps bow, and 2 inches with the 306-fps bow. At 20 yards, deer dropped 2.5 inches and 0.25 inches, respectively.

Years ago, I’d always wait until a deer had its head down to release my shot because I assumed it was calm or eating something. After viewing many shots on video, it became very apparent the opposite is true.

When a deer has its head up, it drops its vitals less than when its head is down. So, the next time you draw on a deer, remember what I just said — video footage never lies!

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One reason this occurs is because a deer can’t drop its head faster than the speed of gravity. If a deer has its head down and it hears something, the deer will throw its head up, which acts like a fulcrum and serves as leverage to push its chest down.

We have all seen deer drop so fast that it looked like their chest hit the ground before they ran away. This happened to me when a deer literally had its head in water and I released my arrow from a ground blind. I could not believe it when I watched my arrow fly over the deer’s back. Again, if I would have waited for it to raise its head, I may have punched my tag.

Additionally, many forget about how the angle of ground surface can affect how far a deer will drop. For example, a deer coming downhill will drop further than a deer going uphill or while standing on flat ground.

Bowhunters will often make some type of noise in an attempt to stop a deer that’s walking within their effective range. Although this practice works, you must be ready to shoot as soon you make the sound. Wait a half-second longer after your sound and the deer may react even quicker.

Through the years, I’ve learned to grunt with my mouth without moving any cheek muscles. This ensures my anchor point doesn’t change and my shot will be perfect — that’s my theory anyway.

There is another factor that might cause a deer to duck your shot: The sound of your arrow in flight.

What many bowhunters don’t realize, is that their arrows can and do make noise while traveling downrange. You might not hear the arrow from your point of view, but it can get very loud once it gets to the target. And although I have no quantitative data to support this, I believe deer are reacting more to the arrow noise than the sound of the bow — especially at longer distances.

Years ago, feather fletching was the norm. Nowadays, shorter/stiffer plastic vanes help us stabilize our arrows much faster than feathers, which in turn leads to better accuracy at longer distances. But compared to feathers, vanes are very noisy. If you don’t believe this, try standing downrange (behind a safe structure) and have someone shoot an arrow with feathers, and one with plastic vanes. The discrepancy of the “whistling” sound between the two is significant.

Considering how quiet today’s bows are, I truly believe it’s more the sound of the arrow in flight, and not the bow, that results in deer ducking. Granted, every bow setup is different, but for shots 30 yards and longer, I believe the arrow’s noise trumps the bow’s when it comes to deer reacting to the shot. I could be wrong, but I’m entitled to my opinion (though some disagree, including the Editor of this magazine).

And what about front-of-center (FOC) with heavier arrow weights? FOC describes the percentage of the arrow’s total weight located forward of the mid-point of the arrow. Having an FOC of 15% or greater can help dampen the vibration of your bow, because heavier arrows absorb more energy than lighter ones coming out of the bow upon release. Potentially, this could help reduce the sound of a bow and the total number of inches a deer drops. Think about it, the speed of sound of the bow would be the same with a high or zero-percent FOC arrow, but the intensity of sound could certainly change a deer’s reaction time.

Granted, not all deer will jump the string, but it’s impossible to determine which deer will duck and which ones won’t. If there is any advantage, my personal experience has shown fewer high misses on deer I’ve shot at early in the bow season, than those I’ve shot at with each passing week of archery season.

Assuming most bowhunters shoot around 275 fps, a good rule of thumb on aiming is the following: Aim a third of the way up from behind the deer’s front leg and two-thirds down from its spine for shots less than 30 yards. Doing so gives you a safety buffer for any errors in your shooting form, or the deer’s reaction to the shot. And, depending on your draw weight/arrow speed, I recommend aiming directly below the belly line for shots 40 yards and longer.

Obviously, you can reduce the impact of deer jumping the string by staying within your effective range (say, within 20 yards), targeting only calm deer, practicing at distances at least 10 yards farther than you would shoot in the field, and by shooting a well-tuned bow.

C.J.’s Summary

If you’re interested in subscribing to GrowingDeer.TV episodes, Dr. Woods sends out new videos every Monday morning. His episode on deer jumping the string can be found here.