Most geese experience comparatively much parental care. How much do juveniles really learn form their parents? Andrea Kolzsch

1. Family movement of
GPS tracked geese
Andrea Kölzsch
Gerard Müskens, Peter Glazov, Helmut Kruckenberg,
Pratik Gupte, Kees Koffijberg, Bart Nolet,
Andrea Flack, Martin Wikeslki

2. Juvenile importance
• Juvenile performance
determines population
dynamics
– Vulnerability
– Dispersion
• Ontogeny of timing and
space use
– Individual learning
– Social learning

3. Extended parental care
• Intensity
• Duration

4. Duration of family cohesion
• Greater white-fronted geese

5. Goose families
• Young learn about
– feeding sites
– dangers
– social behaviour
– migration
• Subadults can help
defend the nest
• Large families dominant
at winter feeding

6. Goose winter dynamics

7. Spatial-temporal dynamics
• Larger families further west in 2nd half of winter
• Adults leave earlier in spring

8. Goose family catching
• 2014 – now:
13 families tagged with Dutch
Association of Goose Catchers

9. Goose family tracking
• Tag design for
juveniles and
better survival
– Growth
– Antennae
– Data download
– Life time tracks

10. Goose family winter movement
• Further
movement of
independent
juveniles,
especially males
Max daily distance

11. Goose family behaviour
• Less resting and more vigilant if with parents
%timeresting
%timevigilant
Without
parents
With
parents
Without
parents
With
parents

12. Goose family splits
• Mostly split just before
spring or during migration
• Disturbance
Day of split event
(day after 1 November)
Probabilityofsplit

13. Goose family reunion
Split 12 Feb 7:00
Rejoin 12 Feb 17:30

14. Goose family reunion

15. Goose family survival
• Juveniles without parents
quickly shot or predated in
spring
Day of split event
(day after 1 November)
Dayofdeath
(dayafter1November)
Still alive
Lost signal in summer

16. Goose family leadership
• Energy saving hypothesis
– V formation flight
– Use of uplift
– Leadership switching
• Communication hypothesis
– Constant angle to keep
together
– Social learning

17. Goose family migration

18. Parental leadership in spring
• Parents
lead
• 80% father
• 20%
mother
• Communic
ation
hypothesis

19. Leadership vs. wind support
• Father spends less energy if
leading
• Father usually leads with
strong tail winds

20. Conclusions
• Many juveniles stay with family all winter
• Differences in behaviour and movement if
with or without parents
• Reunion after splits possible
• Parents lead during migration
– Communication and learning

21. Outlook
• First juveniles with transmitters returned this
winter
– compare tracks

22. Thanks
• Ganzenflappers
• Goose observers & ringers