In Michigan's Upper Peninsula, deer groups with a fawn used roads mainly by day and overlapped the schedules of four carnivores 24 to 38% less than adult deer without fawns did. Black bears, bobcats, coyotes and wolves appeared on the cameras mostly at night while people appeared by day. Groups with fawns overlapped people 39% more than adults without fawns did, so an August daylight photo of a doe with fawns shows a fawn-season schedule and tells you little about when bucks and dry does use that same road.
IDaytime Roads
Deer With Fawns Used Daylight Roads That Carnivores Used at Night
Kautz and colleagues published the study in Ecology and Evolution in 2022. The researchers set 300 cameras on unpaved roads in the western Upper Peninsula from 2017 to 2019 and tracked 777 radio-collared deer captured from 2009 to 2019. Traffic was the human threat on those roads, and every collared deer killed by people died in a vehicle collision.
Our rule is to divide your July to September daylight road and trail camera photos into two piles for groups with fawns and adults without them, then use only the adult pile to judge your site's daylight traffic for bucks and dry does. The study's camera work ended on September 15, so begin both piles again with your October photos.
IIRoadside Cameras
Groups With Fawns Overlapped Coyotes the Least and People the Most
Researchers set the cameras beside gravel roads, logging roads and off-highway vehicle trails in 6 arrays within the summer ranges of collared herds. Across 34,810 camera days the researchers recorded 16,193 independent deer detections. Of those detections 3,596 showed groups with at least one fawn.
The authors measured overlap between daily activity curves using a scale on which 1 would mean matching schedules. Groups with fawns overlapped coyotes less than any other carnivore, scoring 0.41 against 0.66 for adult deer without fawns. Overlap with people ran the other way, at 0.71 for groups with fawns and 0.51 for adults without fawns. Mean overlap with people and the four carnivores was 56% for groups with fawns and 72% for adults without fawns.
IIICollared Fawns
Carnivores Killed About Four Times as Many Fawns as Vehicles Did
The collared deer included 232 fawns and 545 adults followed individually from mid-July to the end of September. The average fawn birth date was June 7, putting fawns at about 5 to 16 weeks old in that window. Deaths totaled 35 fawns and 15 adults. Fawn mortality in that window ran 16% against 3% for adults, which the authors described as 5.3 times greater.
Coyotes caused the most fawn deaths, followed by vehicles, bobcats, black bears and wolves. Adult kills were highest for wolves followed by vehicles and coyotes. No single cause killed more than half of either the fawns or the adults that died. Among deaths with a known cause, carnivores and people caused 94% of fawn deaths and 87% of adult deaths while disease caused the rest. Predators the researchers could not name killed 20% of the fawns that died.
Swipe table to see every column
| Cause of death | Fawn mortality rate | Adult mortality rate | Fawn risk weight | Adult risk weight |
|---|---|---|---|---|
| Coyote | 0.04 | <0.01 | 0.37 | 0.15 |
| Human (vehicle collision) | 0.03 | 0.01 | 0.21 | 0.38 |
| Bobcat | 0.02 | 0.00 | 0.21 | 0.00 |
| Black bear | 0.01 | 0.00 | 0.12 | 0.00 |
| Wolf | 0.01 | 0.01 | 0.08 | 0.46 |
The authors used those deaths to weight risk by each killer's share of deaths with an identified predator or human cause. Coyotes had the biggest share of fawn risk at 0.37, and wolves had the biggest share of adult risk at 0.46. The authors counted about four times as many fawns killed by carnivores as by vehicles. When the authors weighted each species' road activity by its share of fawn deaths, daylight emerged as the least risky time for fawns to use roads.
The authors think groups with fawns moved toward vehicles as a daytime threat that posed less risk than the four nocturnal carnivores together. The authors wrote that mortality risk for adults without fawns was low and "may not have triggered an avoidance response." Our coyote and fawn guide looks at what fawns gained from coyote removal at one South Carolina site.
IVAdult Schedules
Bucks and Does Without Fawns Followed Nearly Matching Schedules
Adult bucks and adult does without fawns in the frame scored 0.93 for overlap with each other, and bucks were slightly more nocturnal. Adult does were more active by day than bucks overall, a gap the authors tied to fawns appearing in 26% of adult doe detections. A daytime photo of a doe with fawns thus tells you little about bucks. Our sunrise and sunset guide looks at collar studies tracking adult movement through fall and the rut.
The authors expected groups with fawns might ease back toward carnivore hours as fawn predation fell in late summer. The cameras did not show that drift within their window. Groups with fawns showed slightly less overlap with people and carnivores in late July, and overlap stayed steady through mid-September. Our read is that a doe and fawn group photographed by day in early September is likely still following its summer schedule.
VSummer Setting
The Finding Came From Quiet Roads With Few Adult Deaths
The cameras ran beside unpaved roads in a mostly forested area from July to September where roads averaged under 1 human detection a day, so the result may not carry to farm or suburban country. The authors describe a unique case of deer, predator and human interactions near roads and note that collared carnivores were mostly nocturnal near roads but not away from them. A Pennsylvania study the authors cite found greater overlap between fawns and predators in a more developed area. Closed deer seasons from July to September left hunting pressure and the rut untested. Overlap shows an association while risk weights count actual deaths, and the authors caution those weights may not match the risk a predator would pose if deer did not avoid it. Only 15 adults died and the cameras missed fawns under 1 month old. A doe photographed alone may also have had fawns bedded out of frame.
NOTES AND SOURCES
- Source: Kautz and colleagues 2022, Ecology and Evolution 12, e9125, white-tailed deer, carnivore and human activity on roads in Michigan's Upper Peninsula.
- Scope: White-tailed deer in Michigan's western Upper Peninsula. Radio-collared deer captured 2009 to 2019 were followed from July 15 to September 30, and cameras at 300 sites on unpaved roads ran from July 15 to September 15 in 2017 to 2019.
- Method: Cause-specific mortality from the collared deer (232 fawns and 545 adults). Daily activity from camera detections, and activity overlap between deer groups and black bears, bobcats, coyotes, wolves and people on a 0 to 1 scale where 1 means identical schedules. A group with fawns is any deer detection with at least one fawn.
- Limits: Observational camera and collar data. Overlap is an association, and the authors' risk index uses realized deaths, which may differ from inherent or perceived risk.
- Limits: Cameras sat on unpaved, low-traffic roads (under 1 human detection per day). Carnivores away from roads were more active by day, so the pattern applies to roads.
- Limits: July to September only. Hunting seasons were closed. No camera data after September 15.
- Limits: Adult deaths were few (15). Camera years (2017 to 2019) are a subset of collar years (2009 to 2019).
- Limits: Groups were classified per detection, so a doe photographed alone could have had fawns out of frame.
- Limits: The text reports 232 fawns monitored and the mortality table note reports 230.
Fully Drawn Research is an independent data analysis desk, not affiliated with any state wildlife agency, transportation agency, mapping provider or outfitter. Fully Drawn Research is an independent data and analysis desk. This paper summarizes published research and adds FDR's reading of what it means for hunters. Figures are quoted from the studies linked in the text, and figures we computed from them are labeled as ours.
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