Ecology from a different perspective

Survey methods, thermal drone surveys and real project examples

Skylark Nest Detection with Thermal Drones

Skylark nest identification can be challenging within larger areas of rough grassland where traditional approaches may require extensive searching or repeated visits. Thermal drones are increasingly being explored as a tool to identify potential nesting locations; however, confidence in species identification and minimising disturbance remain important considerations.

Aerial Ecology carried out preliminary testing using early morning thermal drone surveys designed to maximise thermal contrast while retaining sufficient daylight for RGB zoom confirmation. The objective was to investigate whether potential nesting locations could be narrowed down before targeted field verification.

Approach tested

The preliminary testing undertaken by Aerial Ecology explored:

  • Thermal drone surveys at approximately 20 m above ground level

  • Early morning survey timing to maximise thermal contrast while retaining sufficient daylight conditions

  • Identification of thermal signatures associated with potential nesting activity

  • Collection of coordinates for later verification

  • Observation of behavioural responses during drone operations

The timing of surveys formed an important part of the approach.

The purpose was not to replace ecological judgement or field verification, but to investigate whether useful detections could still be achieved from a greater distance while reducing the need for unnecessary ground searching..

Survey Timing Considerations

Survey timing formed an important part of the approach tested.

Flights were undertaken during the early hours of the morning to maximise thermal contrast while retaining sufficient daylight conditions for use of the RGB camera and zoom functions.

The intention was not simply to detect heat signatures, but to provide additional information that may help narrow down potential nesting locations before field verification takes place.

This may reduce the number of locations requiring manual investigation by an ornithologist and therefore reduce unnecessary disturbance associated with wider searching efforts.

Detection versus confirmation

Thermal detections should not automatically be interpreted as confirmed skylark nests. Thermal imagery can be used to identify potential locations of interest and reduce the area requiring investigation, but species identification and nest confirmation may still require targeted follow-up work by an ornithologist

Preliminary Observations

During testing:

  • Potential nest locations could be identified and georeferenced

  • RGB zoom imagery could assist with review of potential detections

  • No obvious evidence of disturbance was observed during flights at approximately 20 m

  • Coordinates could be used to support targeted follow-up work where required

One potential advantage of this approach is that likely nesting locations can be narrowed down before field verification takes place.

Rather than requiring extensive searching of larger areas, an ornithologist may only need to investigate a smaller number of targeted locations identified during thermal review. The intention is not to remove field verification, but to reduce unnecessary disturbance and improve survey efficiency.

These observations are preliminary and should not be interpreted as evidence that higher flight altitudes are universally suitable.

Future development may include computer vision-assisted review of thermal detections. If detection confidence can be improved, higher survey altitudes and faster survey coverage may potentially be achievable while maintaining stand-off distances.