Do Deer Follow the Moon? Charts Against Collar Records

IStand Talk

Yesterday's full moon and tonight's quiet woods

Hunters who believe in lunar effects answer yes. GPS-collar doubters say lunar effects are barely detectable in collar records.

IILunar Followers

Believers credit the moon with setting movement schedules

Among 1,439 hunters in a survey by Mississippi State, 83% credited the moon with an influence (25% phase alone, 13% position alone, 45% both). Responses to a Penn State Deer-Forest Study reader poll totaled 1,679 and reached 88% agreement. Neither group came from random sampling.

John Alden Knight's solunar predictions date to 1926. They assign major activity peaks to the moon passing directly above or below and minor peaks to its rising and setting. Their highest ratings fall around the new moon and full moon.

Jeff Murray's guide and Adam Hays give lunar position more weight than phase. Their claim links "red moon" days to daylight buck movement when the moon passes above or below near dawn or dusk. Hays points to his personal records spanning 16 years.

John Eberhart, Michael Hanback and Lee Lakosky connect full moons with nighttime feeding. In their account deer eat throughout the night before feeding again around midday. They say clouds erase that pattern. Hanback favors the moon's dark period because he says darker nights shift activity toward daylight. Mark Drury and Lakosky emphasize when the moon rises and sets. They favor afternoon hunts as a waxing moon rises and morning hunts following the full moon unless weather takes priority.

Believers regard findings from 36 Georgia trail cameras across two seasons as their strongest structured evidence, with Outdoor Life reporting the results. The cameras recorded 37.5% of mature-buck sightings on forecast days representing about 10% of the month.

IIICollar Doubters

Skeptics find little lunar influence in GPS records

Biologists make up most of the skeptical camp, with the Mississippi State Deer Lab leading it. A GPS collar records the animal's position at intervals of 15 to 60 minutes throughout daylight and darkness. Skeptics consider that the strongest available test. They say lunar effects in those records barely register beside dawn, dusk and breeding season.

A direct Mississippi State test of red-moon periods detected no clear difference around dawn or dusk. Skeptics also argue that successful predictions stick in hunters' memories and moonlight helps cameras detect deer.

IVResearch Results

Modest effects without a common pattern

For effect size, Mississippi's records put movement during the hour surrounding dawn and dusk roughly 48 yards per hour above baseline. Peak breeding activity added 142 yards per hour. Lunar effects reached only a few yards at their largest. Skeptics argue that an hourly difference of a few yards won't alter which deer pass a stand during a three-hour sit. Believers counter that statistical significance matters and Auburn's effects are real.

Among the studies we located, every study measuring daily travel distance or overall activity reported no clear change in the total. Believers answer that their claim concerns movement timing. A deer can rearrange its nighttime activity without increasing daylight movement while you're hunting.

Each of the two Auburn studies matched solunar predictions in about half of the tested windows. Their matching halves differed. Free-ranging Mississippi bucks followed neither result. Roseberry and Woolf's older Illinois test from 1986 detected no consistent effect. Skeptics argue that the charts fail to predict movement according to their stated rules. Stephen Ditchkoff's Auburn group takes a middle position. It considers positional effects real while rejecting the order of importance assigned by the charts.

Most of the research we cite showing "some effect" measures nighttime activity, camera detections or vigilance. Vigilance means time spent watching for danger. East Texas cameras operating at night recorded 578 deer during full moons compared with 232 during new moons (Ladine and Settles in 2020). Deer at North Carolina bait sites showed more feeding and less vigilance in moonlight (Lashley et al. 2014). Skeptics question whether more deer are present at the bait in moonlight or whether the camera detects them more easily.

Phase labels and actual illumination also differ. Lunar phase explained only 60% of the moonlight recorded, whereas the moon's height and position explained up to 92% (Smielak 2023). Research using brightness models finds modest effects as in Goethlich 2020. Studies relying on phase labels generally detect none.

The animals, places and seasons differ too. Penn State followed does during October. Mississippi and Auburn followed bucks. The direction of Goethlich's doe results reversed between seasons. Combining seasons can therefore erase an effect. South Carolina's study location contained 59 feeders and food plots. The Alabama location enclosed deer behind a high fence. Among hunted deer, activity shifts toward nighttime (Kilgo et al. 1998, Little et al. 2016). Almost none of the studies we located separates hunting pressure's influence from lunar illumination.

VOur Collar Analysis

Another set of records

We conducted one analysis using publicly available GPS-collar records. The initial group included 79 deer across western Virginia and Illinois. We then repeated the analysis with 59 suburban deer from Staten Island. Together those groups contain 138 deer with about 770,000 movement steps spanning 2016 to 2021. Our hourly moonlight model combined lunar height and phase with NOAA cloud observations. We held temperature and time of night constant while comparing each animal against itself within each month.

The model linked moonlight with different movement timing while showing barely any difference in the total. Modeled dawn and dusk movement declined in both regions. Staten Island bucks were an exception. Across all our data sets the model showed breeding-season bucks moving more with bright moonlight. It showed suburban does moving less.

Believers interpret the decline around dawn and dusk as the full-moon pattern hunters describe during hunting hours. Skeptics take those same results to mean that daytime activity and total movement changed little.

The Virginia and Illinois group includes 61 does alongside 18 bucks. Those bucks had 2-hour location fixes and their sample was too small to support firm results for bucks alone. Hunting pressure went unrecorded at all sites. Airport stations supplied the cloud observations. Speeds calculated along straight lines connecting fixes miss the animal's actual route between locations and its final approach to a stand. This observational first pass has not been peer reviewed.

VIRemaining Gaps

The choice stays yours

Almost all the GPS research we located comes from southern sites or covers October alone. Our search found no GPS study examining lunar effects during the rut in Midwest or northern deer. Much of the moon discussion comes from those places. We found no study testing whether the decline around dawn and dusk also occurs among rutting bucks on hunted Midwest land. Our next data set will test that question. Three more questions are open. Are apparent effects of lunar position real or do they follow from how sunrise and sunset line up? Can feeders or high fences produce lunar effects? Would another study repeat the modest Georgia camera finding?

Four questions remain for you. Does a change in movement timing matter to hunters when the overall amount barely differs? With the two Auburn studies returning opposite solunar findings are the charts wrong or partly right? Would an 8% decline around dawn and dusk change your chosen hunting days? Which carries more weight with you, hunting records collected over decades or a few hundred collared deer?

Believers choose "red moon" dates from Murray's guide. Their other choices include afternoons with a rising moon and mornings following the full moon (Drury and Lakosky), midday hunts following a bright full moon (Eberhart, Hanback and Lakosky), or mornings around the new moon (hunters favoring dark moons).

Skeptics tell hunters with limited available days to hunt those days. They give dawn and dusk, the timing of the rut, wind and pressure priority over lunar predictions. They leave solunar charts aside and keep the day following a full moon in play. Their reason is that none of our three herds showed a clear daylight difference following nights with a full moon. Hunters taking a middle position and accepting our dawn and dusk estimates lean a little toward mornings and evenings under darker moons when their schedules allow. They treat lunar conditions as a way to break a tie between days rather than build a hunting plan.

For the question of why deer might react to lunar illumination at all, see our paper on moonlight, deer eyes and predators.