We fly full deer counts from December through mid-March, before dawn. That timing comes from how thermal cameras work and from what field studies have found.
The camera needs contrast
A thermal camera doesn't see deer. It sees temperature differences. A deer stands out when its body is much warmer than the ground around it. On a 20 °F January morning that difference is large. On a muggy July night it can nearly disappear. A 2023 study of white-tailed deer in Texas found that detection depends on air temperature, and projected that more counties will become too hot for reliable summer surveys as the climate warms.
Leaves hide deer
Thermal cameras can't see through leaves. A 2025 study in Iowa found that while green-up was sparse, almost no deer were in places a drone couldn't survey; as spring green-up progressed, the share hidden in unsurveyable forest rose above half. Leaf-off canopy means fewer deer missed and a tighter range.
The coldest hour
Ground and rocks give off heat they absorbed during the day. By the last hour or two before sunrise, the landscape has cooled as much as it will, and deer stand out most clearly. That's when we fly.
What it means for you
- Book early. Good survey nights are limited by weather, and windows fill in order.
- Plan around board calendars. A January or February count delivers numbers before spring meetings, when next season's program is set.
- Seasonal questions still get answered. Movement flights in spring, summer, and fall show how deer use the land, with wider ranges stated in the report.
Reserve a winter count window.
Sources
- Scientific Reports (2023): climate change and planning aerial wildlife surveys with drone-based thermal cameras
- Delaney et al. (2025), Ecological Applications: availability of deer for drone surveys during spring green-up (Iowa)