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Results
Preliminary Results of NestCams
(1) Does the frequency of egg turning behaviour differ between Greylag geese and Northern bald ibis?
Figure 1. Frequency of egg turning behaviour per incubation week and species (i.e. Greylag geese and Northern bald ibis). N Greylag geese=8, N Northern bald ibis=3.
The Northern bald ibis showed a decline in the egg turning from week one until week three and an increase in week four. However, as this data is only based on three individuals, the data has to be carefully interpreted.
The Greylag geese showed a stable level of egg turning during the first three weeks and a slight decrease in week four.
(2) Does the frequency of egg turning change with incubation day in Greylag geese?
Figure 2. Frequency of egg turning behaviour in relation to incubation days in Greylag geese. Mean time of incubation is depicted by the green box and is approximately round 28 days of incubation. N=8.
As we only have three individuals of Northern bald ibis in our dataset at the moment, the subsequent analyses focused only on the Greylag geese.
The number of incubation days ranged between 22 and 31 days in the Greylag geese. Incubation day had no effect on the egg turning frequency.
(3) Does the mean ambient temperature and daytime affect the frequency of egg turning behaviour in Greylag geese?
Figure 3. Frequency of egg turning behaviour in relation to mean ambient temperature.
Egg turning frequency increased with increasing mean ambient temperature.
Figure 4. Mean ambient temperature distribution for each of the four daily intervals.
To address the question whether individuals show more egg turning behaviour at a specific daytime, four intervals were computed ranging from 05:00 AM to 7:00 PM.
The ambient temperature during the incubation period ranged from -7.5 °C to 28.3 °C. The mean ambient temperature for each of the four daily intervals is shown in Figure 4.
Figure 5. Frequency of egg turning in each of the four daily intervals. N=8.
The frequency of egg turning behaviour increased from first daily interval to the second daily interval, but remained constant during the third and fourth daily interval.
(4) Does the experience of having a nest (i.e. egg laying & incubation) affect the frequency of egg turning behaviour in Greylag geese?
Figure 6. Frequency of egg turning behaviour in relation to previous experience of having a nest in Greylag geese. N=8.
The experience of having already had a nest in previous years was defined as follows:
(number of nests already had/number of possibilities to have a nest)*100
The experience of having already had a nest did not influence the egg turning frequency in Greylag geese.
(5) Does the experience of hatching (i.e. egg laying, incubation & hatched goslings) affect the frequency of egg turning behaviour in Greylag geese?
Figure 7. Frequency of egg turning behaviour in relation to previous experience of hatching in Greylag geese. N=8.
The experience of having already had successfully hatched goslings in previous years was defined as follows:
(number of times having already had successfully hatched goslings/number of possibilities to have hatched goslings)*100
The experience of having successfully hatched goslings did not influence the frequency of egg turning behaviour in Greylag geese.
The preliminary analysis was done in the course of a student internship in cooperation with @Thomas_Eckhardt, @AlexandraStiegler, @stefanie.alice.hofer, @PatriciaBerner.