This document discusses new insights into bird migration provided by geolocator tracking devices and the key questions and challenges they present. It contrasts the migration of wood thrushes, which exhibit flexibility, and purple martins, which display more rigid migration patterns. Geolocators have shown that wood thrushes can change their migration timing and route between seasons, while purple martins maintain consistent departure dates and pacing. However, geolocator use presents challenges like low return rates, habitat shading of location data, and potential effects on bird behavior.

1. L. Elliot New Discoveries in Bird Migration Using Geolocators : Questions & Challenges Kevin Fraser & Bridget Stutchbury

3. L. Elliot MarieRead Migratory Songbird Declines Wood Thrush Bobolink

4. Geolocators 1.5g

5. Key Questions Seasonal carry-over effects (life history tradeoffs) Connectivity between breeding and wintering populations (songbird declines, demographics) Migration strategy (phenotypic plasticity)

6. Key Questions Seasonal carry-over effects (life history tradeoffs) Connectivity between breeding and wintering populations (songbird declines, demographics) Migration strategy (phenotypic plasticity)

7. (4) Challenges

8. 2. Migratory Connectivity High Connectivity Low Connectivity

9. Where does a single breeding population over-winter? n = 23 Stanley et al., in prep.

10. Where does a single wintering population come from? n = 15 n = 1 Belize Costa Rica

11. High Connectivity & Demographics Stanley et al., in prep.

12. Stopover Connectivity Spring Migration Fall Migration

13. Connectivity in Purple Martins 38 geos retrieved to date, 237 deployed 2011

14. 31 Aug 25 Apr 5 Sept – 1 Oct 20 Apr 13 Oct 12 Apr

15. 31 Aug 25 Apr 5 Sept – 1 Oct 20 Apr 13 Oct 12 Apr Fall: 304 km/d Spring: 577 km/d

16. Low Breeding-Wintering Connectivity

17. male female

18. Implications for Demographics Purple Martin Wood Thrush High Connectivity Low Connectivity

19. 3. Programmed vs PlasticMigration Strategy Rigid migration schedules imply genetically controlled, or programmed, migration Conklin et al. 2010

20. Geographic Variation in Migration Route Purple Martin

21. But Fall Departure Date DoesPredict Winter Arrival Date

22. 3 Populations Similar Fall Migration Pace Zone 1 Zone 2 Zone 3

23. Male and female pace similar Bill Dalton

24. L. Elliot Fast vs Slow Fall Migration Strategy Wood Thrush

25. Plasticity in Wood Thrush Relocate mid-summer Rapid Fall Migration Long Spring Stop Long Fall Stop Spring Circum-Gulf Late Breeding Arrival

26. Plasticity in Wood Thrush 1801-85920 07-08 08-09 09-10 Relocate mid-summer Rapid Fall Migration Long Spring Stop Long Fall Stop Spring Circum-Gulf Late Breeding Arrival

28. Fall departure date does not predict arrival date

30. Fall departure date does predict winter arrival

32. 4. Challenges Influence on behaviour? Retrieval = sample size Habitat shading Data only for survivors Equinox and latitude

33. 4. Challenges Influence on behaviour? Retrieval = sample size Habitat shading Data only for survivors Equinox and latitude

34. Influence on behaviour? Typical return rates = 50-60% 2008 = 10% Bill Dalton

35. Influence on behaviour? Typical return rates = 50-60% 2008 = 10% Reduced load by 30% 2009 = 15%

36. Influence on behaviour? Typical return rates = 50-60% 2008 = 10% Reduced load by 30% 2009 = 15% Reduced stalk length (20 mm to 5-8mm, 15° angle) 2010 = 50%

37. Influence on behaviour? Typical return rates = 50-60% 2008 = 10% Reduced load by 30% 2009 = 15% Reduced stalk length (20 mm to 5-8mm, 15° angle) 2010 = 50% Geo stalks create drag during flight (Bowlin et al. 2010) - Not an issue for Wood Thrush

38. Sample Size Low return rates – particularly for naïve migrants Solution – colonially nesting purple martins 26% return rate

39. Sample Size Combine with stable-isotope analyses – do geolocator coordinates match isotope assignments?

40. Habitat Shading – Geo design Short stalk = most days unuseable Longer stalk = better resolution *WOTH – stalk length did not influence return rates

41. L. Elliot Summary Geolocators provide new insights into connectivity and migration strategy Contrast WOTH & PUMA Can reduce challenges by effective study and geo design

42. Questions? Kevin Fraser: fraserkev@gmail.com Postdoc at Stutchbury lab: http://www.yorku.ca/bstutch/ Bill Dalton