elks96
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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).
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).