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Updates

18

Apr

Winter 2017-2018 Update

The new Deer-Elk Ecology Research Project Update is now complete.

 

Check it out!

WinterUpdate_20172018_Final

 

IMG_7851

05

Feb

Coyotes in the Greater Little Mountain Area

Due to the relatively high levels of predator-related mortality on mule deer fawns, especially by coyotes, we wanted to look more closely into what was influencing such high predation. To do this, we began capturing and collaring coyotes in April 2017 to better understand how they use habitat during mule deer and elk parturition time periods. To date, we have 11 coyotes collared in the study area– 4 males and 7 females. Generally, the coyotes we have captured have been young (1-3 years old) with the exception of one female that was around 6 years old. We captured this female in April of 2017, and she was pregnant with 2 pups at the time. On average, these coyotes have weighed around 25 pounds, although we have captured 2 male coyotes that weighed just over 40 pounds!

What are the coyotes doing?

Although we have not conducted any formal analyses, the GPS data from coyotes thus far is interesting to look at. On average, our coyote home ranges look to be about 56 square kilometers (21 square miles), which is typically what is reported in other areas in the West. There is, however, fairly large variation in individual coyote home range sizes with the largest spanning over 279 square kilometers (100 square miles), and the smallest at 1.84 square kilometers (0.5 square miles). The reason for the disparity among all of these home ranges is unknown at this point, but is likely in part due to some coyotes being residents and others transients searching for open territories.

 

Stay tuned as we continue to capture coyotes and learn more about their movements!

Movement of coyotes throughout the study area. Each color represents a different coyote.

Movement of coyotes throughout the study area. Each color represents a different coyote.

 

Coyote home ranges throughout study area. Each color represents a different coyote.

Coyote home ranges throughout study area. Each color represents a different coyote.

 

Attaching a GPS collar on a coyote

Attaching a GPS collar on a coyote

 

17

Oct

Fawns 2016 versus 2017

Given the longitudinal nature of our research, we are able to compare variations in fawns during captures from year to year. Comparing timing, sex, size and cause of mortality of fawns helps us understand how these animals are responding to environmental conditions. These details are made more important by the fact that we can’t grow deer if we don’t have fawns; understanding the dynamics associated with fawns helps us understand this vital piece of the population.

During the 2016 season we captured 55 fawns from our collared female deer and this summer we caught 54 fawns.  We noticed a shift in parturition time from 2016 to 2017, with parturition coming much earlier this year. The first live fawn was born on May 24th, compared with the 31st of May in 2016.  Peak date of parturition was May 31 of this year compared to June 10th in 2016. We also saw a difference in the percentage of overall fawn loss between 2016 and 2017. In 2016 we saw a 75% mortality rate over just the summer months compared to this year at about 33% mortality of our collared fawns.

Fawns in 2017 were also generally smaller in size, which is likely correlated to shorter gestation periods and early parturition dates as compared with typical years. Average fawn weight and length in 2017 was 3.1 kg (~6.8 pounds) and 60.1 cm respectively while average fawn weight and length in 2016 was 3.8 kg (~ 8.4 pounds) and 60.5 cm respectively.

2016_2017FawnCa

17

Oct

Migration or Dispersal?

One interesting and perhaps anomalous pattern occurred on 15 June of 2017. A male fawn that was captured as a newborn during summer 2016, and that we were able to recapture and put a GPS collar on in the spring of 2017, departed what appeared to be his summer range just north of Pine Mountain in the southeastern portion of the study area. In just 2 short days, this 1-year old male moved north, crossed I-80 between Rock Springs and Green River, and is currently residing north of Pilot Butte, west of Rock Springs.

The timing and decision to “migrate” in the middle of summer is a bit abnormal, and the location of his movement likely is more reflective of a dispersal event where he is establishing a new summer range. It begs the question if he will return, or perhaps establish a new winter range this autumn. Time will tell if this young male retains some of what he learned during his upbringing, or if he simply has adopted an entirely new movement strategy. It is possible that this could be an important link in determining why buck:doe ratios have remained stagnant in the face of extremely limited harvest. Are young males dispersing to try and find better ranges to occupy? Is this a common occurrence? Hopefully we’ll be able to answer these questions at the conclusion of our work.

Mig

17

Oct

Neonate Captures Summer 2017

The summer of 2017 began our second field season capturing and monitoring mule deer fawns from our radiocollared females. In addition to fawn work, we initiated our first field season of capturing and monitoring elk calves that belong to the 35 adult female elk that are collared for the study. These monitoring efforts aim to assess cause-specific mortality, recruitment into the population, sex ratios, and to detail potential dispersal from the population.

This summer we caught 54 fawns 17 elk calves belonging to our radio-collared females. Of these 54 fawns, 30 were males, and 24 female, almost a 50/50 split. Interestingly, over 80% of the calves captures were male. On average, fawns weighed about 3.1 kg (~6.8 pounds), compared to elk calves that weighed on average 21.6 kg (~47 pounds), over 8 times the size of a mule deer fawn!

CalfFawnBirthPlot

17

Oct

Vaginal Implant Transmitters

Vaginal Implant Transmitters (VITs) are a central piece of equipment used to identify birth sites and locate newborn fawns. The VITs that are used for the DEER project are equipped with a VHF transmitter along with technology capable of communicating with mom’s collar.

During the few weeks before parturition, mom’s collar will attempt to communicate with the VIT on an hourly basis. As long as the VIT remains in place, mom’s collar will stay in communication with the VIT. When a VIT is expelled, however, mom will lose communication with the VIT, indicating that a birth event may have occurred. There are two additional triggers that signify a birth event. First, the VITs are equipped with a temperature sensor that detects when the ambient temperature has fallen below 32° C (~90° F), indicating that the VIT has been expelled. The VIT is also equipped with a light sensor that is triggered by increasing light, another measure used to indicate a birth event. If any of these sensors are triggered we receive a notification via email and will then investigate.

VIT

BS1 BS2

17

Oct

Expanded Coyote Work

This spring marked the start of capturing and collaring coyotes as an expansion of the DEER Project. Due to the high mortality rate of DEER Project fawns in 2016, predators, particularly coyotes, have come into a sharper focus as potentially playing an important role in the deer population south of Rock Springs. The addition of the coyote work will not only give us a better idea of how they are using the landscape, as well as the territories they occupy, but will also give us an idea of how they are responding to parturition timing of mule deer and elk and if they are altering their behavior during this crucial period.

In cooperation with our capture crew, we were able to capture and collar 4 coyotes opportunistically while catching deer and elk during the Spring 2017 captures. Crews did not actively seek out coyotes but worked any coyotes they happened to see while capturing our collared animals. Though we hope to have a sample between 20-30, this was a jump start on collaring efforts for coyotes. GPS data has begun to arrive on our collared coyotes and, so far, has shown us that coyotes have very large territories in this area, some exceeding 50 mi2. Additional data will help us understand the degree to which this predator could be structuring ungulate populations in the Greater Little Mountain Ecosystem.

Coy

17

Oct

Expanded Elk Work

Like mule deer, Rocky Mountain elk are an iconic species of the West and also are cherished by hunters, conservationists, and wildlife enthusiasts worldwide. Although some elk populations have suffered declines, most populations throughout the West have prospered through an expansion of their range and increase in abundance in recent decades. Elk initially recolonized the Greater Little Mountain Area (GLMA) in southwest Wyoming in the late 1940s, and have remained mostly stable or increasing since that time. Decades after recolonization, elk in the GLMA remain at or above desired objectives, whereas mule deer have failed to recover to historic levels.

The GLMA is a high-desert ecosystem characterized by a diverse vegetative community of subalpine fir at high elevations to salt desert shrub and sagebrush at lower elevations along Flaming Gorge Reservoir. High-desert systems harbor some of the most highly coveted elk hunting opportunities in the West, and are world-renowned for quality elk harvested in these areas—the GLMA is no exception. With harvest success rates for elk well above 70 percent in the GLMA, it’s no surprise that big game hunters spent $4.8 million to pursue elk in the GLMA in the past five years. Despite liberal harvest throughout the area, elk continue to thrive suggesting high reproductive output and survival in this population.

For obvious reasons, most elk research aims to understand the factors influencing populations that are declining or exist at a fraction of historic population levels. Although the motivation behind this type of research is meaningful and necessary to understand the causes of elk decline, we have a unique opportunity in the GLMA to take a proactive approach in understanding the “recipe” for a productive and healthy elk population in an effort to maintain robust herds of elk in some of the most coveted areas that exist in high-desert systems. Being such a prized and cherished area to hunters and outdoor enthusiasts alike, the GLMA serves as an ideal laboratory for high-caliber research in hopes of understanding the factors that maintain species that the GLMA is renowned for.

We are excited to announce a new partner of the Deer-Elk Ecology Research Project. The Wyoming Wildlife and Natural Resource Trust (WWNRT), a key conservation agency whose mission is to enhance and conserve wildlife habitat and natural resource values throughout the state, has provided critical funding to the DEER Project, and of which also will allow for the opportunity to examine survival, and cause-specific mortality of elk calves. This means that in addition to capturing mule deer fawns in the upcoming summer, we will be capturing, collaring, and monitoring elk calves belonging to our radiomarked adult female elk in the GLMA. Our goal is to understand nutrition and reproduction of elk, by examining calf survival and recruitment while simultaneously examining contributions of habitat selection, nutritional condition, and age of the mother, as well as predation, weather, and disease to understand what factors contribute to maintaining productive and healthy elk herds in high-desert systems of the West.

17

Oct

Nutritional Condition and Vital Statistics

During our spring 2017 capturing effort, we captured or recaptured 30 female elk, 46 female mule deer, 19 yearling males and 3 yearling females that were captured as neonates in summer of 2016. We aim to keep a sample size of 35 adult elk and 50 adult female mule deer at all times, however, keeping our sample size is not always possible because weather conditions, collar malfunctions, mortalities, and accessibility of animals to capture. Of the 30 elk that we caught 28 were pregnant and of the 46 mule deer that we caught, 44 were pregnant. All pregnant female elk had a single fetus while fetal rate for our mule deer was 1.5 as compared with 1.7 for the spring of 2016.

Condition of deer south of Rock Springs was actually better in the spring of 2017 compared with their condition in the spring of 2016. This is in stark contrast to mule deer in the Wyoming Range who were in the poorest documented condition in the spring of 2017. Winter was harsh throughout western Wyoming but the Wyoming Range herd was harder hit than herds elsewhere in the state. Deer south of Rock Springs were able to increase their condition over the summer of 2016 more so than deer in the Wyoming Range who have access to typical high-quality alpine summer ranges. As we continue these studies we will be able to reveal patterns and processes behind these data to help determine the status and trajectory of our mule deer populations throughout the West and the state.

DEERP_WWNRTUpdate_08252017

17

Oct

April 2017 Captures

During our Spring 2017 capturing effort, we recaptured 30 female elk, 46 female mule deer, 19 yearling males and 3 yearling females that were captured as neonates in summer of 2016. We aim to keep a sample size of 35 adult female elk and 50 female mule deer at all times; keeping our sample size is not always possible because weather conditions, collar malfunctions, mortalities, and accessibility of animals to capture.

The spring also began the start of our expanded elk work to track neonatal survival, dispersal, and recruitment into the population. Of the 30 elk that we caught 28 were pregnant and were fitted with Vaginal Implant Transmitters (VITs) to determine birth site locations and to help in neonate capture and monitoring efforts. All the female elk had one neonatal fetus. Of the 46 mule deer we caught, 44 were pregnant and fitted with VITs. Our mule deer had a fetal rate of 1.5 as compared with 1.7 for the spring of 2016.

DEER PROJECT HELI SLINGING 1 WOLD 2015 DEER CAPTURE NOV 1 2015 FOR MATT HAYES WOLD