1. 1
Bicknell's and Swainson's thrushes in
regenerating New Brunswick clearcuts:
niche separation by nest site and diet
Emily A. McKinnon, Kevin C. Fraser,
Antony W. Diamond
University of New Brunswick, Fredericton
2. 2
Outline
• Intro
– BITH and SWTH
– NB context
– niches
• Part 1: Nest site
– nest patch vegetation
• Part 2: Diet
– trophic niche width
– SIA
• Summary
11. 11
Nest patch characteristics
= non-nest site
= nest site
• 5-m radius
patch centered
on the nest
• non-nest
patches
selected 100m
away from nest
patch
12. 12
Nest patch analyses
• Nest patch data biologically meaningful
variables
– Snags
– % balsam fir
– Small trees
– Hardwoods
– Total density
19. 19
‘New’ method to quantify diet
• Stable Isotope Analysis (SIA)
• Isotopic niche = trophic niche
15
N/14
N
15
N/14
N
15
N/14
N
15
N/14
N
14
N
14
N
14
N
28. 28
Summary
• BITH choose nest patches on a small
scale
• Suggests ability to nest in small patches?
• SWTH nest patches are less specific
• less affected by management?
• BITH - Type 2 generalists
• Individual specialization?
• SWTH - Type 1 generalists
• reduced competition with BITH?
29. 29
Future work
• Nest patch
characteristics- How
flexible are they?
• Diet throughout the
season
• Could blood tell us
where BITH or SWTH
came from?
30. 30
Acknowledgements
• Committee: Dr. D. MacLean, Dr. D. Keppie
• T. Vanbuskirk, B. Whittam, G. Campbell, C. Rimmer, K.
McFarland, A. Albert, R. Aracil, H. Askanas, K. Friars, M. Godin,
C. Wegenschimmel, Operations 1 Staff, Mark McLelland at the
Governor’s Lodge