289
Finally, UAV flights provide added-value to the classical colony survey methods
by producing, as the main output, a map including the location of the target species.
Thus, for instance, one can investigate the relationship between nest density and
clutch as a possible factor driving breeding success. On the other hand, 3D points
derived from stereocorrelation may also enhance the automatic bird delineation by
adding the subtle differences in height between birds and the ground (Anderson and
Gaston 2013).
Conclusions
– We could provide accurate estimates of Slender-billed Gull colony size (lying
birds) and productivity (number of chicks) by using UAVs flights.
– Flights did not cause any disturbance to the gull colony.
– Visual photo-interpretation always performed better than automatic supervised
classification.
– Although automatic classification produced satisfactory estimates, minimum
class patch size had to be defined to discard features other than birds.
– Monitoring bird colonies with UAVs in comparison to ground surveys resulted in
faster procedures and in sufficiently accurate colony size and productivity
estimates.
Practical Lessons for Nature Conservation
• Estimating the number of breeding pairs and/or the number of chicks in
bird colonies is an essential monitoring activity to inform on the conservation of protected species.
• Ground surveys usually require costly procedures and often generate disturbances to the colonies.
• Nowadays, UAVs flights can be easily carried out to map any interesting
feature for nature conservation
• Image geometric processing is also easily and successfully achieved by
using both commercial and free software.
• Visual identification of ground nesting birds in the orthomosaics is an
affordable task for any user and can be cross-checked by several users.
• Automatic classification is also available in open source software. This
provides quick and reliable estimates but does not easily distinguish
between bird species.
Using UAVs to Map Aquatic Bird Colonies
Finally, UAV flights provide added-value to the classical colony survey methods
by producing, as the main output, a map including the location of the target species.
Thus, for instance, one can investigate the relationship between nest density and
clutch as a possible factor driving breeding success. On the other hand, 3D points
derived from stereocorrelation may also enhance the automatic bird delineation by
adding the subtle differences in height between birds and the ground (Anderson and
Gaston 2013).
Conclusions
– We could provide accurate estimates of Slender-billed Gull colony size (lying
birds) and productivity (number of chicks) by using UAVs flights.
– Flights did not cause any disturbance to the gull colony.
– Visual photo-interpretation always performed better than automatic supervised
classification.
– Although automatic classification produced satisfactory estimates, minimum
class patch size had to be defined to discard features other than birds.
– Monitoring bird colonies with UAVs in comparison to ground surveys resulted in
faster procedures and in sufficiently accurate colony size and productivity
estimates.
Practical Lessons for Nature Conservation
• Estimating the number of breeding pairs and/or the number of chicks in
bird colonies is an essential monitoring activity to inform on the conservation of protected species.
• Ground surveys usually require costly procedures and often generate disturbances to the colonies.
• Nowadays, UAVs flights can be easily carried out to map any interesting
feature for nature conservation
• Image geometric processing is also easily and successfully achieved by
using both commercial and free software.
• Visual identification of ground nesting birds in the orthomosaics is an
affordable task for any user and can be cross-checked by several users.
• Automatic classification is also available in open source software. This
provides quick and reliable estimates but does not easily distinguish
between bird species.
Using UAVs to Map Aquatic Bird Colonies