Interesting Mule Deer Study information...

elks96

Long Time Member
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My family and I worked the last several days on a mule deer study in NW Colorado. It was amazing how much I learned and how the system worked. I could write a ton on everything and have a bunch of pictures to share at a different point.

Some big take thoughts:

First take away, the deer are fragile as hell in the spring. They have multiple studies going on with several different groups of deer. Including fawns.

On fawns, even with the warm temperatures the last 2 weeks the guys are picking up 1 to 3 dead fawns every 24 hours. They are just so weak that even with the warm temps they are still dropping hard. Those that are not dropping from low body mass are easy targets for predators as they do not have the energy left to run for extended time. This year was especially hard on fawns because of the heavy snow and thick crust. Many fawns were killed by coyotes running on top of the crust while the deer were breaking through. Coyote populations were believed to be up because of the very high rabbit populations in the areas the last 3 years. This year the rabbit population crashed leaving lots of hungry coyotes.

Expected fawn winter mortality will be over 60% in the area this year. Significantly higher than average. Doe mortality will be much lower and closer to the average. The lead researcher did not want to quote a number as they are still not sure how good or bad it might be.

Next big take away. Even a deer that "looks" good is not nearly as good as a person thinks. They use a 1-6 body condition score system. 6 being as fat as a mule deer can get. 1 being deathly thin. I was surprised how many deer came in that initially appeared to be healthy but when actually checked were 1.75-2.25 body score. In all honesty between a 1.75 and 4 I could see no physical difference at all. Unlike judging live stock, there are not many good visual markers for overall body score. A 1 was pretty obvious as muscle is depleted and fat reserves are all gone etc. But still a 1 with a relatively healthy coat was deceiving.

Rump fat was measured on all the deer we handled. The researcher was catching the same doe in March that he had caught and measured in early December. They use an ultrasound to measure the fat thickness on the rump. In many cases the fat thickness on the rump was only 2-3 mm. Very thin and an important indication as to how much energy the deer had already exerted in the winter. We had very few deer with 4MM of fat. I never got an idea what the fall test showed for rump fat thickness going into the fill but I would bet it was closer to 30mm.

Almost every single doe we checked was pregnant with twins. It was really rare to find one that did not have twins, even more rare to find one that was open. I believe in the 58 we processed only 2 were open. One of the 2 was doe aged at 10.5 years. She had a great body score and good fat, but did not have a fetus.

Deer mortality due to vehicles was very low and in the research populations was one of the lowest identified causes of death. This includes 2 separate populations, one that only crosses county roads and another that typically can cross one if not 2 state highways. Of course the group that crosses the highways show a higher rate of vehicle mortality, but it was still not identified as a leading cause of death.

My informal observation that maybe validated with data... Areas with habitat treatments (removal of pinon and junipers) had a significant impact on the body score and fat thickness of the animals. Especially in the fawns that were captured measured in the fall vs. spring. In one area of the study they did over 100 small scale habitat treatments that were 5-100 acres max in size. The deer we processed from this area had slightly higher fat thickness, a slightly larger loin depth and slightly better BCS. This was just from my informal observation.

During our off time, I was lucky enough to look at the data recording software and most importantly look at the GPS locations on different collars. What the collars showed was simply amazing. The one doe we looked at for example wintered in a very small area every year. We looked at her data from 2013 to 2016. Her winter "range" was right at 2.5 square miles with 90% of here locations in the "winter months" being in this area. There were only very few points where she was outside of this area and when she left this area in the winter is was only for a short time before moving back. Also from this data it was amazing how extremely routine the migration pattern from summer to winter and winter to summer were. I was virtually the same exact path each year. On the map you could see where she was crossing the same saddle in the spring and in the fall. Her summer range was even smaller than winter range. Almost all summer she was in the same 1 square mile area. The only time she spent significant time out of this area was having her fawn. this doe for some reason would go almost 5 miles away from her home area to fawn then in 2 weeks be back in the same area presumably with her fawn. We looked at data from 3 or 4 doe and saw very similar patterns. One doe showed the data from being caught by the helicopter and flown to the research station. It was amazing to see where her home winter range was, the location where she was darted, where she was tested/measured and how long it took her to get back to her home range.

Mule deer are such creatures of habit. The deer that showed her her capture, flight and return. She was caught north of a test location. She was netted given drug to make her loopy (high). Flown approximately 4 miles dropped off, handled by humans, and then released still intoxicated by the drugs enough to show some effect. In 2 days, she had crossed back over the river, crossed the highway and fences and was back with in 100 yards of where she was captured.

I wish I had more time to just look at the maps, collar locations and all the data.

In addition to Body Condition score and rump fat. On dead animals they would attempt to use bone marrow for a score, and if the kill is fresh enough they would gut an animal and look at membrane thickness as well. If the animal was even fresher and complete they would freeze the entire animal and send it to the state lab for a full work up.

I am sure there is a lot more I could share...

This last weekend we were recapturing does they had processed in the fall. We were running same test, but if they were pregnant they were fitted with a VIT (Vaginally inserted Transducer) which remains in the animal until they go into labor. Once the VIT is expelled during labor the researchers go to the vit and attempt to locate the fawns and measure them for the study etc. I will be back up in June to help find the neonats (neonatal or little babies).
 
Very interesting stuff! I'd be curious to know do the deer migrate to the same area regardless of snow depths, or do they only go when the snow gets deep?


2a0fcsk.gif
 
Thanks for the story and great info! It seems like everything about them is so much more complex than any other big game animal!
 
>Very interesting stuff! I'd be curious
>to know do the deer
>migrate to the same area
>regardless of snow depths, or
>do they only go when
>the snow gets deep?
>
>
>
2a0fcsk.gif


I did not ask that detail, but using this last year as an example and having hunted this unit every year since 1990. I can say this, snow depth does not seem to matter much. A little early snow may get them moving sooner than later, but a lot of the deer we were seeing are the same deer that were there this November for the 3rd rifle season. If you know anyone who hunted this year in the unit you would know that the hunting was very hot and very dry. Yet we killed our bucks (2 of them) right in the middle of the winter research areas. They were there because the doe were there... I have my personal theory and was not able to manipulate the data much, but I fully believe the mass migration occurs on the last full moon in October. In odd years where the moon is split with a 1st week of October and the 1st week of November, It seems like some come early and some come late. However a full moon from October 15-25 is a mass flow of deer into the area.

The lead researcher is Chuck Anderson. I might be able to have him look and see if any of it corresponds to moon data. I heard this theory years ago from a hunting Guide in Craig and have often "seen" this to be true. I am not sure if it is just a self-fulfilling hypothesis and i only see what I want to see or not.
 
I have witnessed the migration of deer in CO during the second season without weather. They just seem to start showing up more and more every day. I never correlated it to the moon phases. I will watch that more closely. Keep adding to this post as you remember what you learned. To me it is fascinating trying to understand such a majestic creature.

Rich
 
Elks what's the span of births and dates of that span? Is it consistently the same dates and length year after year?
 
>Elks what's the span of births
>and dates of that span?
>Is it consistently the same
>dates and length year after
>year?

They told us the target dates when the fawns hit the ground is June 8th to the 10th. This is by far the busiest 2 days and fawns are dropping all over the place. The researchers say there is always one pain In the butt doe who drops on 4th of July. There are some as early as the last week of May but vast majority drop June 8th to 10th.
 
Fantastic information! Thanks for sharing. Very interesting. I hope you can educate us more........

Brian Latturner
MonsterMuleys.com
LIKE MonsterMuleys.com
on Facebook!
 
I have spent quite a bit of time in NW Colorado during 3rd and 4th season. The one thing I noticed was the carnage of deer hit by vehicles. From Craig to Baggs and from Craig to Meeker. A high fence would really help with the loss of deer. There were bones found as far as a hundred yards from the roadway from the deer hit then managed to get away from the road and then die. It's a shame that Colorado does not feel that vehicles are not a big problem on deer and do something to help with their survival.
 
>I have witnessed the migration of
>deer in CO during the
>second season without weather.
>They just seem to start
>showing up more and more
>every day. I never
>correlated it to the moon
>phases. I will watch that
>more closely. Keep adding
>to this post as you
>remember what you learned.
>To me it is fascinating
>trying to understand such a
>majestic creature.
>
>Rich

Just like teal migration...100 degrees and they start showing up. Photoperiod has a big influence in how animals are wired.
 
>I have spent quite a bit
>of time in NW Colorado
>during 3rd and 4th season.
>The one thing I noticed
>was the carnage of deer
>hit by vehicles. From Craig
>to Baggs and from Craig
>to Meeker. A high fence
>would really help with the
>loss of deer. There were
>bones found as far as
>a hundred yards from the
>roadway from the deer hit
>then managed to get away
>from the road and then
>die. It's a shame that
>Colorado does not feel that
>vehicles are not a big
>problem on deer and do
>something to help with their
>survival.

I would strongly oppose any such fence. Sure it may mean fewer deer and elk getting hit, but it would also cut off the largest migrating elk and deer herds from their summer and winter ranges. In a stretch of highway that is over 40 miles long the cost to build enough over or underpasses to support the current herds and their migration routes would be astronomical. Not to mention that such fences will greatly impact the migration of the animals (see above how the deer on collars are using the same trails and crossing the same locations every year). Just north of Baggs they built a fence but it was only a couple miles long. In those few miles there are at least 3 to 4 designed underpasses. Most of the deer eventually adapted to the under passes, but the first couple of winters the deer were stacked up against the fence and eventually starved in significant numbers as they paced up and down the fence trying to figure out how to cross. Even now years after the fence has been built you can see deer spend days walking back fourth across the same 200-300 yards of fence wanting to head west. During this time they are not eating and are expending a great deal of energy.

As for your comment about the state not caring, this is totally untrue. They have tried and with some success decreased the animal vehicle collision rates in this area. For several months all fines for speeding on the highway are doubled, for several years there was lower speed limit enforced for traveling between 5pm and 7am. That speed limit showed a significant decrease in issues.

The last point is that while we see lots of animals in the spring after the melt etc. The actual over all percent of deer killed by vehicles is relatively low. The real reason to build wildlife fences is for the sake of humans and not for the sake of the animals.
 
This is awesome information. Thank you so much for sharing what you could. I find it especially interesting in relation to the massive uproar of some of the Utah shed hunting folk who claim that running around the hills looking for antlers early in the year doesn't have any affect on the animals as a whole. Hopefully once finalized this data can be used to inform some of those people.
 
I would disagree with you about high fences and over/underpasses. These have been a Godsend in Wyoming. In the Nugget Canyon country, fences and underpasses were built a few years ago. While the deer initially were reluctant to go through the underpasses, once the first doe went through, the floodgates opened! Trailcams were set up to monitor deer movements, so it's all verified. Passage through these underpasses is now ingrained in this herd. Fawns do what mom does; they go where mom goes. Once behavior is taught, it becomes ingrained. Instinct.

Wyoming big game/vehicle collisions number over 2,000 annually. 85% of those deaths are mule deer. Bear in mind this number is only the reported incidents. How many truckers with the huge grill guards hit them and just keep going? Nugget Canyon underpasses have reduced deer deaths by approximately 400 per year. If we can save even half the deer hit by vehicles in a year, that's a very substantial number! The underpasses north of Baggs are reporting similar numbers of deer being saved proportionately. Elk and many other species use the underpasses as well.

Big game overpasses near Daniel Junction north of Pinedale have reported similar success. Big game over/underpasses absolutely WORK!! Yes, the costs are astronomical, but how much are lives worth?? Deer or human???!!!

SW Wyoming has a study underway doing the same research!

Thanks for the info, Elks!
 
>I would disagree with you about
>high fences and over/underpasses. These
>have been a Godsend in
>Wyoming. In the Nugget Canyon
>country, fences and underpasses were
>built a few years ago.
>While the deer initially were
>reluctant to go through the
>underpasses, once the first doe
>went through, the floodgates opened!
>Trailcams were set up to
>monitor deer movements, so it's
>all verified. Passage through these
>underpasses is now ingrained in
>this herd. Fawns do what
>mom does; they go where
>mom goes. Once behavior is
>taught, it becomes ingrained. Instinct.
>
>
>Wyoming big game/vehicle collisions number over
>2,000 annually. 85% of those
>deaths are mule deer. Bear
>in mind this number is
>only the reported incidents. How
>many truckers with the huge
>grill guards hit them and
>just keep going? Nugget Canyon
>underpasses have reduced deer deaths
>by approximately 400 per year.
>If we can save even
>half the deer hit by
>vehicles in a year, that's
>a very substantial number! The
>underpasses north of Baggs are
>reporting similar numbers of deer
>being saved proportionately. Elk and
>many other species use the
>underpasses as well.
>
>Big game overpasses near Daniel Junction
>north of Pinedale have reported
>similar success. Big game over/underpasses
>absolutely WORK!! Yes, the costs
>are astronomical, but how much
>are lives worth?? Deer or
>human???!!!
>
>SW Wyoming has a study underway
>doing the same research!
>
>Thanks for the info, Elks!

Yeah but does any of those deer in the under pass areas actually get hunted into the November migration and rut? Colorado is a different animal in regards to our hunting seasons. Can you imagine what hunting would look like just north of Baggs on November 5th? People would be lined up on the fence just waiting. Also If you read my comment this is over 40+ miles of road. To build an over or under pass every mile for 40 miles would cost so much the state would never go for it. Instead they would fence the whole darn thing and have only a couple under/over passes. I agree the Baggs Fence works well for Baggs, but it is also very short and in a small very specific spot. There are lots of deer that cross further north and get hammered, but is it feasible to build a fence from Baggs to the Highway?

Fences if done right are a ood thing, but sadly my cheap ass state will not even fix a 3 foot pothole let alone build a good deer fence.
 
Strange how that deer herd goes to the same location every year for summer and winter. In California the deer move around all over the place. One year you'll see the herd in one area and the next year they might be 10 miles away. I've seen this for some blacktail herds and some mule deer herds.
 
Thanks Elks, superb info. Did I understand that coyote predation of fawn is a result of weak fawns combined w a cyclical high population of coyotes, w fawns being weakened by poor habitat? My readings state habitat quality is a bigger factor in fawn recruitment than predation.
 
>Thanks Elks, superb info. Did I
>understand that coyote predation of
>fawn is a result of
>weak fawns combined w a
>cyclical high population of coyotes,
>w fawns being weakened by
>poor habitat? My readings state
>habitat quality is a bigger
>factor in fawn recruitment than
>predation.

Great Question. I actually was able to research and look at the study data prior to this year in this area. I will work on a summary of the take aways in terms of habitat and the issues with regrowing our deer herds. This might lend itself to whole new thread. I will work on that tonight.
 
Elks96...did you or the biologist happen to do the math backwards? If the majority of fawns drop in early June, given the gestation period in a mule deer...what is the magic date deer get bred (the most) each year?

I could google "deer gestation length" but am curious what the biologist said.

Apologize in advance if I missed that somewhere.

thanks...
 
>Elks96...did you or the biologist happen
>to do the math backwards?
> If the majority of
>fawns drop in early June,
>given the gestation period in
>a mule deer...what is the
>magic date deer get bred
>(the most) each year?
>
>I could google "deer gestation length"
>but am curious what the
>biologist said.
>
>Apologize in advance if I missed
>that somewhere.
>
>thanks...


203 days puts it at 2nd and 3rd week of November.
 
LAST EDITED ON Mar-16-17 AT 12:36PM (MST)[p]Gestation period for mule deer is about 203 days, which is 29 weeks.
If they plan on most does fawning June 8-10th, most does would be bred around Nov 18-19th according to my calculations.

The rut is later in southern states like NM and AZ, fawns would be born later in the summer.
 
Elks,

I have personally worked on this study for a summer and a little chunk of the fall. They are doing awesome work and getting great data. They are finding out some cool stuff. The habitat treatments could prove to be a huge boost to mule deer numbers found there. Thanks for the update. Oh and fyi VIT actually stands for vaginal implant transmitter.
 
I did my senior project on something similar to this but in the state of WA on Black tail and Roosevelt elk, crazy to see how these animals work and what they do,

Thanks for the info and super great fun read!
 
Nontypical I agree with you. Nugget Canyon and around Pinedale has saved thousands of deer and elk and antelope. Colorado can afford it with the tax they make off of the Wacky Tobacky. Not only does it save money from insurance companies and destroying vehicles it helps the wildlife out. It is a win win for everyone.
 
Elks96- Very valid point about the late season Colorado hunts. We don't have many of those in Wyoming. I have heard that was/(is?) a problem with the Paunsaugant herd in southern Utah when they migrate into Arizona with hunters(?) piling up near the underpasses during season. I know this was a problem during the first year or two, but haven't heard anything since. Anyone got an update?

As far as needing an underpass every mile, that is a bit of a stretch. Migration trails are the same; year in and year out. Deer don't just suddenly decide to go another way when they migrate. You build the underpasses in those select areas where deer are most likely to cross the highway. Yes; costs are high for these types of projects. That is why they are usually funded from many sources. There IS a way! This can be done for the benefit of deer and humans!

Sorry it took so long to reply. I don't hit this site daily.

If those dang deer would just cross where the deer crossing signs are, we wouldn't have this problem!! :)
 
Thanks much for the information, appreciate your taking the time to not only volunteer to help out the researchers, but to post some of that information here. Mr. Anderson has done some good work, no doubt about it.

Do you think you might be able to find out more information on the critters that had a more in depth necropsy completed, such as the type of tests? That would be very interesting to be able to follow up on.

For those interested, here is an article written a couple of months ago that's related:

[http://www.hcn.org/articles/colorad...ion-cougar-black-bear-predator-for-mule-deer]

Some very interesting work done by Mr. Anderson:

[http://cpw.state.co.us/learn/Pages/ResearchMammalChuckAnderson.aspx]

Wildlife managers and biologists are still trying to understand and get a better handle on mule deer migrations, let alone the many facets that affect their population dynamics and survival.

Thanks again...
 
>Elks96- Very valid point about the
>late season Colorado hunts. We
>don't have many of those
>in Wyoming. I have heard
>that was/(is?) a problem with
>the Paunsaugant herd in southern
>Utah when they migrate into
>Arizona with hunters(?) piling up
>near the underpasses during season.
>I know this was a
>problem during the first year
>or two, but haven't heard
>anything since. Anyone got an
>update?
>
>As far as needing an underpass
>every mile, that is a
>bit of a stretch. Migration
>trails are the same; year
>in and year out. Deer
>don't just suddenly decide to
>go another way when they
>migrate. You build the underpasses
>in those select areas where
>deer are most likely to
>cross the highway. Yes; costs
>are high for these types
>of projects. That is why
>they are usually funded from
>many sources. There IS a
>way! This can be done
>for the benefit of deer
>and humans!
>
>Sorry it took so long to
>reply. I don't hit this
>site daily.
>
>If those dang deer would just
>cross where the deer crossing
>signs are, we wouldn't have
>this problem!! :)


Sadly the CDOT does not work well with out CPW. As a result the new 40 miles of Fence in Eagle county appears to have no wildlife crossings.
 
>Thanks much for the information, appreciate
>your taking the time to
>not only volunteer to help
>out the researchers, but to
>post some of that information
>here. Mr. Anderson has
>done some good work, no
>doubt about it.
>
>Do you think you might be
>able to find out more
>information on the critters that
>had a more in depth
>necropsy completed, such as the
>type of tests? That
>would be very interesting to
>be able to follow up
>on.
>
>For those interested, here is an
>article written a couple of
>months ago that's related:
>
>[http://www.hcn.org/articles/colorad...ion-cougar-black-bear-predator-for-mule-deer]
>
>Some very interesting work done by
>Mr. Anderson:
>
>[http://cpw.state.co.us/learn/Pages/ResearchMammalChuckAnderson.aspx]
>
>Wildlife managers and biologists are still
>trying to understand and get
>a better handle on mule
>deer migrations, let alone the
>many facets that affect their
>population dynamics and survival.
>
>Thanks again...


The advanced will look at many things and do more extensive testing. They are looking at CWD, BLue Tongue, Respiratory infections like Pneumonia, etc. IN the test they also do a much more in depth body score by using membrane fat samples and bone marrow samples to determine fat levels. They also look for any other other injuries that may not have been apparent at time of death.
 

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