Does moon phase really affect deer activity?
As an outfitter who hunts on some of the most storied ground in the country, Darrin Bradley is always looking for a leg up on trophy bucks. So, in 1994, he started keeping track of his personal deer observations and those of his hunters, along with weather data.
“I wanted to collect statistics related to weather and moon phase and compare the results of my and my hunters’ success and deer sightings,” he said. “I assumed the moon would have a noticeable effect on deer activity. I basically thought the more moonlight there was, the less deer activity there would be during the daytime. I hoped I would be able to predict deer activity based on moon phase and increase the success rates of my hunters.”
He’s not alone. The moon and its perceived effect on all things living has been the subject of myth and mystery for as long humans have been capable of rational thought. Crime skyrockets on a full moon, we’ve been told; more people end up in emergency rooms; and births increase. Even the words lunatic and loony are based on the word lunar.
There’s no question the moon is a powerful body. It pulls the oceans to create the constant rise and fall of the tides. But numerous scientific studies have shown that it has zero effect on human behavior. Crime does not increase on a full moon. People don’t freak out, fall off ladders or drive their cars into trees.
THE HUNTER’S PERSPECTIVE
As Bradley learned, it doesn’t have a noticeable effect on deer activity, either. After 614 deer observations cross-referenced with various weather and moon phase data, Bradley, who owns Missouri-based IMB Outfitters, came to this sobering conclusion: There is little, if any, correlation between moon phase and deer activity.
“I recorded wind conditions, food availability, temperature, moon phase, precipitation, commercial scent usage, number of deer seen, number of bucks seen, and the number of bucks seen wearing antlers exceeding a minimum of 130 inches,” Bradley said.
Overall, there was no significant difference in deer activity throughout the observation period. Bradley saw whitetails 52 out of 72 times, or 72 percent, during a full moon, and saw deer on 77 percent of his outings during the waning crescent phase. Overall, deer sightings ranged from 77 percent to 60 percent throughout the eight defined phases of the moon. The new moon phase, which produces the least amount of reflected light, accounted for 26 deer sightings out of 42 hunts, the lowest of all his observation periods.
Before his personal study, Bradley believed the widely accepted notion that deer move less during the day in periods of bright moonlight, and more during the day when the moon is producing far less light.
“If they can see better at night, it makes sense they would move more at night and less in the daytime,” he says. “That wasn’t what I found, though. We killed seven mature bucks during five different moon phases.”
He delved further into his data and examined buck activity and the number of sightings of bucks estimated to score 130 inches or more. Again, there was no correlation between the amount of light reflecting off the moon and deer activity. Bradley saw the most bucks during the moon’s first quarter phase, a dark period, and nearly as many during the full moon.
What he couldn’t explain, though, was the fact that daytime sightings of bigger bucks were actually higher during a full moon than any other phase. Of the 56 bucks over 130 inches, he saw 12 when the moon was full.
Could there be more to the moon than the amount of light it produces, or was it just chance? Bradley saw the fewest bucks during the darkest moon phase. The rest were scattered throughout the six other defined phases, so it’s tough to say if there was any correlation.
David Moreland, former deer project leader for the Louisiana Division of Wildlife and Fisheries, used remote cameras to record the activity of a trophy class buck over three years on a 1,200-acre Louisiana property that does not get hunted. He placed one camera on each of seven feeders in 2010 and 2011, and one on each of five feeders in 2012. While not a peer reviewed study, his work shed some light on buck activity as it related to moon phase.
“There seems to be some relationship with scraping activity to moon phase, because the scrape initiation period, the time when bucks first open up old scrapes, occurs at some point between the new moon and the full moon. I looked at this for several years, and it was always at this time — never between the full moon and the new moon,” Moreland said.
He photographed two bucks throughout the three years. Both followed the same pattern. They were regular visitors to feeders between the full moon and the last quarter during the pre-rut.
When the 2011 rut kicked in, the larger buck disappeared for two weeks between the new moon and full moon. It came back to the feeders from the full moon to last quarter, and then disappeared again from new moon through full moon. It came back and fed during the last quarter.
“That was a year when there were no acorns, so deer were using the feeders if they wanted high-energy foods in their diet,” Moreland recalls.
A year later, the bucks followed the same pattern in the pre-rut, feeding heavily from the full moon to the new moon. The larger buck disappeared when the rut started, and the smaller one visited the feeder sporadically.
Moreland said he thinks food sources and weather play a larger role in whitetail activity than moon phase. He noted that 2012 was a good year for acorns, and the absence of the bucks coincided with the acorn drop.
As to whether moon phase affected the timing of the rut, he said he didn’t see any data that would indicate the rut depends on the moon. “In Louisiana, our visible rut activity is dependent on the weather,” he said. “If the winter is warm, daytime deer activity greatly declines.
Most reproductive studies identify the peak two weeks for breeding based upon historic data gathered by measuring fetuses and calculating the date of conception. In areas with a shorter rut cycle, the calculations are highly accurate. As a result, most biologists agree the rut occurs at about the same time every year, regardless of moon phase.
North Carolina State University graduate research assistant Marcus Lashley is one of them. He examined previous research projects conducted in Alabama, Tennessee, Maryland and his own research conducted on whitetail does in North Carolina to determine if lunar cycles had any influence on deer activity. It is likely the most comprehensive examination of the moon and its effect on whitetails ever conducted.
“I had 250,000 locations from more than 100 deer from these studies and compared them to the moon phase at the time the data was gathered,” he said. “I found no significant relationship at all. I looked at the periods of three weeks before and three weeks after the peak rut periods and found no consistent trends when I compared buck activity to moon phase. The rut takes place about the same time every year.”
Lashley even compared deer activity to solunar tables, which use the sun’s location and moon’s phases and location to predict the best times to be in the woods.
“You could throw a dart at a dartboard and have the same chances of seeing a deer as if you went by the solunar tables,” he said. “What I found was, across the board, peak movement times were in the mornings and evenings, with evening activity a little higher than morning activity.”
Lashley admits there was one slight difference in buck activity in relation to moon phase.
Bucks tended to move a little more at night on a full moon and during the darker moon phases typical of a new moon. They moved more in mornings and evenings during the crescent phases.
However, it was such a small difference he wouldn’t base his hunts around it. A lifelong bowhunter, Lashley wanted to find some relationship between lunar cycles and deer movement to give him an edge in the woods.
So did Bradley. In the end, both agreed it’s best to hunt every chance you get, no matter how loony that sounds.
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This article was published in the August 2013 edition of Buckmasters Whitetail Magazine. Subscribe today to have Buckmasters delivered to your home.