The quantitative study of marked individuals in ecology, evolution ...

EURING 2003 Radolfzell
covery models, whereas female survival estimates were consistent with those from
band recovery models. We suspect the difference between sexes in survival estimated
from multistate models was due to higher rates of neckband loss in males compared
to females, as has been found in numerous other studies, and/or higher rates of
permanent emigration by males from sampled areas. The importance of violating model
assumptions depends upon the biological parameter of interest, and whether inference
is restricted to the sample population or extended to the entire metapopulation.
10:10 AM - 10:25 AM break
10:25 AM - 10:45 AM
Modelling Dolphin Behaviour using Multi-State Models with Time-Varying Covariates
S. Brooks & R. King
Effective management is the key to the protection of many endangered species.
Identification of the primary factors affecting survival will often lead to the introduction
of strategies to improve survival rates. In this talk, we consider a small population of
Hector's dolphins located of the coast of New Zealand and the impact that the establishment
of a seasonal sanctuary has on their survival and migration rates. We use a
multi-state model to describe the movement of the dolphins around the habitat and
adopt a Bayesian approach using reversible jump Markov chain Monte to distinguish
between a wide range of competing models. We also examine the impact of the inclusion
of time-varying covariates such as catch-effort information and demonstrate
the added value that these data provide in terms of both model discrimination and parameter
estimation. In particular, we find a whole class of models that provide a far
better fit to the data (and therefore better prediction and ultimately better management)
than those adopted in previous analyses.
10:45 AM - 11:05 AM
Spatial distribution of breeding Pied Flycatchers Ficedula hypoleuca in respect to
their natal sites
L. Sokolov, N. Chernetsov, V. Kosarev, D. Leoke, M. Markovets, A. Tsvey, A. Shapoval
Research project on the study of philopatry and dispersal of Pied Flycatchers Ficedula
hypoleuca has been underway on the Courish Spit on the Baltic since 1980. A
total of 8006 nestlings were ringed in the Russian part of the Courish Spit. In subsequent
years, 512 individuals (6,4%) were recaptured in the whole study plot, 300 males
and 212 females. The aim of this study was to test two alternative hypotheses
proposed to explain the distribution of breeding Pied Flycatchers in respect to their
natal site. The breeding area imprinting hypothesis (Löhrl 1959, Berndt & Winkel
1979, Sokolov et al. 1984) assumes that in spring, migrants try to return to a relatively
small area, with a radius of one to several km. The other hypothesis forwarded by Vysotsky
(2001) suggests that all first-year birds and many adults in spring arrive randomly
to an area much larger than the initial study area. In 2000, some 800 nestboxes
were added so that their overall number reached 1340 and the length of the
study plot reached 44 km. To study natal dispersal, we compared the observed distribution
of natal dispersal distances with the distribution derived from the model assuming
random arrival to the study area. Significantly more Pied Flycatchers were recaptured
within several km from the natal site that at larger distance, and this was not
a function of the control effort. Therefore, it is concluded that the home area imprinted
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