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| Marjorie
Sorensen
Tel: +44 (0)
1223 331 861
Fax: +44 (0) 1223 336 676
Email: mcs70 at cam.ac.uk
Position held:
Gates Cambridge Trust funded PhD Student (supervisor: Claire
Spottiswoode)
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| Research |
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My
PhD research will focus on the winter ecology and conservation of
migratory birds that travel between their breeding grounds in Europe
and Asia and their wintering grounds in sub-Saharan Africa. These
long distance migrants are currently experiencing catastrophic population
declines and most research to date has focused on the breeding grounds
in Europe, leaving gaps in our understanding of the factors that limit
individual success in Africa.
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Prior
to Cambridge:
During my M.Sc. at the University of Guelph, Canada,
I studied Cassin's Auklets, a Pacific seabird population that
has declined by 80% since the 1970s. The factors influencing
this decline were poorly understood partly because previous
research has focused almost exclusively on the breeding season
since tracking individuals during the winter on the open ocean
is extremely difficult. I used stable carbon and nitrogen isotopes
in feathers to examine the effect of winter diet quality on
reproductive success the following summer. I found that in Cassin's
Auklets females that fed on high quality zooplankton prey during
the winter were able to breed earlier and produce larger eggs
the following summer
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In addition, I
studied the effect of winter diet quality on sexual ornament size
in the Rhinoceros Auklet. Horns and plumes are used in sexual selection
but the factors affecting ornament growth are unknown. I found that
adults that fed on high quality prey during the winter were able to
grow larger ornaments the following spring, suggesting diet quality
during the winter is important for acquiring a mate. |
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| Publications |
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- Sorensen,
M.C., Hipfner, J.M., Kyser, T.K. & Norris, D.R. (2009) Carry-over
effects in a Pacific seabird: stable isotope evidence that pre-breeding
diet quality influences reproductive success. Journal of Animal
Ecology 78: 460-467
- Sorensen,
M.C., Hipfner, J.M., Kyser, T.K. & Norris, D.R. (2010) Pre-breeding
diet and ornament size in the Rhinoceros Auklet Cerorhinca
monocerata. Ibis 152: 29-37
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Department of Zoology, University of Cambridge, Downing Street, Cambridge
CB2 3EJ, U. K. |
