The use of drones to study the breeding productivity of Whooper Swan Cygnus cygnus

Figures & data

Figure 1. Study areas and Whooper Swan Cygnus cygnus breeding locations.

Figure 2. A Whooper Swan Cygnus cygnus adult with six cygnets at one of the study sites within the study area. 2 August 2022. Photo by Dominik Marchowski.

Table I. The number of sites occupied by Whooper Swans (Cygnus cygnus) assessed through ground observation and drone surveys in the spring (first survey) and summer (second survey) with a sample size of 38 in the survey area.

Period of survey	Method	Number of sites with birds	Number of sites with no birds	Confirmed breeding	% Sites with birds
spring	ground	31	7	25	81.6
spring	drone	32	6	21	84.2
spring	ground+drone	36	2	32	94.7
summer	ground	18	20	16	47.4
summer	drone	26	12	22	68.4
summer	ground+drone	29	9	24	76.3

Figure 3. Productivity of Whooper Swan Cygnus cygnus assessed using the traditional ground observation and drone survey (N = 36). Dots – all data; rhombus – mean; whiskers – standard error.

Table II. Reproduction in Whooper Swan on the Górowo Heights in 2022 as shown by the standard ground and drone methods for two surveys separately (spring, summer) and for both surveys combined.

Method	Number of breeding pairs (probable and confirmed)	Number of successful pairs	Total number of cygnets	Mean number of cygnets per pairs ± SE	% of pairs with breeding success
ground	32	16	70	2.19 ± 0.44	50.0
drone	28	22	104	3.71 ± 0.48	78.6
ground+drone	36	24	112	3.11 ± 0.44	66.7