| description: |
It has been shown that chicks of birds with similar structural size (in respect of tarsus length or body mass) are actually in different stages of skeletal development. As it is usually difficult or impossible to discriminate between fledglings at different developmental stages solely on the basis of biometric measures, additional indicators are essential. In this respect, a biochemical marker, namely bone alkaline phosphatase (ALP), may facilitate assessment of the maturity of chicks at the pre-fledging stage. The activity of bone-ALP is associated with bone calcification processes. Although in wild birds age-related variation in total-ALP activity have been demonstrated in several studies, no evidence is known about direct connection between bone mineralization, growth rate and enzyme activity of chicks. Our purpose is to test whether ALP activity in blood plasma might serve as a reliable marker for the ossification of the skeleton in birds, hence being a general measure of development. For that longitudinal studies will be planned where variation in ALP activities in the blood is measured along with a complete characterization of skeletal development in chicks of two passerine birds, the great tit Parus major and the pied flycatcher Ficedula hypoleuca. Both descriptive and experimental methods will be applied in order to estimate developmental rate of chicks in relation to growth conditions, age and sex. As an academic result of the study, we hope to provide a novel technique very useful for physiological ecologists (ALP could serve as a marker of delayed skeletal development of chicks prior to fledging). ALP activity can also be used in conservation biology as a population-specific marker giving valuable information about growth conditions in different habitats or between different geographical regions. It may also facilitate prediction of post-fledging survival in wild birds based on subtle physiological differences between chicks prior to fledging. The results will be published in international peer-reviewed journals.
|