C-DRONE GUIDE · 4 AUGUST 2026
Saving fawns from mowers with a thermal drone: method, organisation, price
From May to July, roe deer does leave their fawns in tall grass meadows — precisely the ones mown in the same period. A fawn's reflex in the face of danger is not flight but total immobility, pressed flat in the grass: the cutter bar gives it no chance, and a shredded carcass can contaminate fodder (botulism from carcasses in silage kills cattle every year). The thermal drone has changed the game: flown at dawn, a field yields the position of every heat spot within minutes. Farmers, hunting federations, wildlife groups and local authorities now organise rescue rounds. Here is the method, and how to set the operation up.
Published on 4 August 2026, reviewed on 4 August 2026 — regulations in force as of August 2026.
Why thermal, and why at dawn
A crouched fawn is invisible: no movement, a dappled coat mimicking shade and light, 40 to 80 cm of grass covering it entirely. Traditional methods — walking the field, dogs, scare poles set the evening before — are slow and unreliable. In thermal imaging, the fawn's body (around 39 °C) stands out against still-cool grass: contrast peaks at dawn, before the sun warms the ground and multiplies false positives (molehills, stones). Hence the typical window: take-off between 5 and 8 am, on the morning of the mowing itself.
The method has long been scientifically validated: as early as 2011, Martin Israel (DLR, the German aerospace agency) published a thermal-drone fawn detection system tested in real conditions (see the study on Google Scholar), and a Danish study by Kim Arild Steen and colleagues in Sensors demonstrated reliable thermal detection of animals in mowing operations (see the study on Google Scholar). Consumer-grade hardware has since made the method accessible: a professional thermal drone covers 10 to 20 hectares per hour on a programmed flight.
How an intervention runs
The evening before, the farmer shares the fields to be mown (map or coordinates). In the morning:
- Automatic grid flight at 50-70 m, thermal camera pointing straight down; every heat spot is pinned on the map.
- Verification: the drone descends and switches to the visible camera to tell a fawn from a leveret, a cat or a molehill.
- Securing the animal: a two-person ground team walks to the GPS point. The fawn is never handled with bare hands (human scent causes abandonment): gloves and armfuls of grass, moved to the field edge or a ventilated crate in the shade, released as soon as the field is mown. In several départements these steps are done with the hunting federation or a dedicated association — a fawn remains a wild animal protected under the French environmental code, moved out of immediate danger, not kept.
- Centrifugal mowing straight after: starting from the centre of the field pushes mobile animals outward.
On the aviation side, the typical mission flies in open category A3 over open rural land — the simplest frame there is; only aerodrome proximity or a restricted zone calls for a check on the Géoportail map.
Organising at municipal or cooperative scale
The hard part is not technical, it is the calendar: mowing is decided on the weather, often the night before, and everyone mows the same week. The set-ups that work pool resources: a municipality, a machinery cooperative or a farming co-op lists volunteer farms in April, one coordinator centralises requests, and the pilot chains fields in a morning round — five to eight farms covered per outing. Some departmental hunting federations and local authorities subsidise these rounds; ask before the season.
For farmers, the operation dovetails with other grassland drone uses — forage biomass estimation, damage assessment — and for land managers with nocturnal wildlife counts: same machines, same skills, complementary seasons. See also our agricultural drone offer.
2026 prices
Orders of magnitude observed in France in 2026 (excl. VAT):
- Morning outing per farm (up to 10-15 ha, heat spots pinned, help securing animals): €150 to €400.
- Pooled round (several farms chained the same morning): €60 to €120 per farm depending on how dense the sector is.
- Season package for a municipality or cooperative (weather stand-by from May to July): quoted case by case.
Fawn rescue is one of the few drone missions where the quote is measured in hours, not days: the dawn thermal window cannot be caught up later. Contact us before the mowing season with the list of likely fields: the stand-by then follows your weather, not the other way round.
Put it into practice
- Drone aerial thermal imaging: rates and cities covered from €500
- Aerial thermal imaging in Mont-de-Marsan Nouvelle-Aquitaine
- Aerial thermal imaging in Nice Provence-Alpes-Côte d'Azur
- Aerial thermal imaging in Toulon Provence-Alpes-Côte d'Azur