Rut influence


New member
Aug 18, 2011
Hey guys, I don't post a lot on here but I am seeking a little help. I am looking to get some input and opinions on the biggest influence in sparking the rut for elk. I have heard numerous times over the years that it's solely dependent on the moon phase yet find in my personal experience it's more driven by the temperature and weather. I put aside 2 weeks out of the year to chase elk in the backcountry and I am hoping the info provided helps me this year, so please feel free to share your experiences and info. Thanks

Ben Long

Well-known member
Aug 8, 2011
Kalispell, MT
Rutting periods for deer and elk follow the length of the day. As days shorten in fall, they trigger changes in the pituitary gland, which triggers changes in hormone levels. There is some local variation, but this is very predictable. But as you've seen, actual game movement depends on other factors, particularly weather. Elk are big and in the fall are wearing a lot of fat and heavy hide, so they conserve energy and are more active when it's cool or on a falling barometer. Weather is a lot harder to predict than the rut, per se. IMO moon phase doesn't have a lot to do with anything but the tide, but others may have different experience. I also think that herd structure has a lot to do with it. Where there are more mature bulls, they will compete and move a lot more than herds with a heavily skewed bull-cow ratio or where bulls are killed off as raghorns.

Big Fin

Staff member
Dec 27, 2000
Bozeman, MT
Ben is right, it is a photo-period dynamic. What many hunters observe as "weather related" is that an elk spends more energy trying to stay cool on a warm September afternoon than he does a cold January night. As such, what we observe as hunters on warm days is that elk are laying low and trying to stay cool during the day, with most their activity is confined to to night, when day time temps are really high. Then, when the days are cool, elk are able to exert a lot more energy in mid-day, so we think it is the weather that kicked the rut into high gear. In reality, it is weather and temps that forced/allowed elk to be less/more active during periods that we are out in the woods chasing them.

Some will argue moon phase until the ends of time. I've not noticed any difference. I have to hunt no matter the weather or moon phase, if I am to get enough episodes each year. I have not noticed any significant differences in activity levels, other than the daily shift of more night time activity when it is really hot.

I suspect each person will have a different observation.


Active member
Jul 1, 2011
+1(and +1) with what Ben and Big Fin stated.

Another way of looking at elk Rutting behavior versus elk breeding is when the elk calves are born each year. If you reverse the number of days for an elk's gestation period . . . . that equates to when the elk was bred or were breeding.

I have heard a lot of archery hunters say, "The elk are not rutting". Well, I interpret a lot of times that the elk are not active and/or vocally active. It may be hot, but they will still breed. Another way to look at it is . . . . if you only got laid once a year (depending on the size of the herd) . . . . . you would be breeding. :)

The moon phase has an impact only on rutting behavior at night. I have seen during a full moon that elk tend to stay out all night rutting and at first light they head to their bedding area. Elk see much better than humans in the "dark", so full moon to them is like a low intense lighted area and they know that humans don't hunt at night (legally).

One other thing I will add is hunting pressure. You can have elk on public land that get hunted quite a bit have totally different rutting behavior than say private property with no or limited hunting pressure that may be just over the hill.


Active member
Aug 9, 2012
Whilst it is proven photo - period does trigger females, there is always a slight variance each year as to peak times due to a combination of factors. In my experience at least it is never a certain date on a calendar when i can say this particular species will be going well, its normally a general guideline that i can work with from past experience and factor these dates into my hunt planning.

Moon phase will have an influence on actual animal movements and simply put cycling of females will trigger vocalisation and 'rutting' behaviour by males. Elk and deer will always be at their best period of vocalisation when females are cycling. However, pressure from hunters, moon phases, terrain, habitat, animal numbers, wind strength etc etc will all have an influence on whether hunters are hearing and/or seeing rutting behaviour.

Just because a hunter pulls up on a ridge and gets out of his car and hears nothing in the basin below him doesn't mean females are not cycling and males rutting/vocalising. So many times i have punched it out different ridges or different areas in a wide range of habits for different species to find the males vocal and going well in a certain area and 2-3 days later things have changed, yet one or two basins/valleys over all is quiet and some guys would think it wasn't going on.

Best advice i could give is to stay out in the field all day as often animals will fire up at odd times when females are cycling and many times i wake up in the middle of the night, and cover ground on big ridges listening for animals to give me an idea of where i should be at the break of day. In the right areas it is even possible to drive around a lot at night and call to get an idea of where it is going on. But the key is to being adaptable and always switching up your game plan if you know animals are in the area but your not locating or hearing them.

If i had to choose a hunt keeping in mind moon i would try to line it up 6-8 days after the actual full moon period, but many don't have flexibility.

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