Social and individual features affecting natal dispersal in the colonial Lesser Kestrel

Causes of natal dispersal were studied in an isolated population of the migratory, facultatively colonial Lesser Kestrel (Falco naumanni) in northeastern Spain. During a seven-year study, we gathered information on natal dispersal of 751 individuals and on 24 explanatory variables that evaluated individual traits, conspecific cues in terms of colony size, and different ecological and populational features. We examined separately whether or not individuals changed colonies and how far they moved. Dispersal from the natal colony was high (83%), and dispersers covered a median distance of 7225 m (range 112-136 500 m). The probability of natal dispersal decreased with the size of the natal colony and with the distance to the nearest colony, but not with the distance to unoccupied buildings, in the year of recruitment. Moreover, the shorter the distance to the nearest colony, the shorter the distances that individuals dispersed, particularly to large colonies (>10 pairs). These results support the conspecific attraction hypothesis. Accordingly, the probability of recruiting in the natal colony increased with the proportion of philopatric adults, although beyond a threshold individuals were prevented from recruiting by the more dominant adults in a despotic way. The timing of arrival from the wintering grounds was positively related to the probability of colony change, especially in males. To the extent that this variable is related to the phenotypic quality of individuals, it reinforces the idea that natal dispersal is shaped by intraspecific competition in crowded colonies. Males showed lower frequencies of colony change and dispersed shorter distances than did females, as explained by the different role of the sexes in nest acquisition and defense. Our results indicate that natal dispersal is an evolutionarily labile trait simultaneously influenced by ecological, social, and individual features both within and between populations.Peer Reviewe

Doppler ultrasonographic examination in sheep

Objective of the present paper is to review applications of Doppler ultrasonography in sheep. Principles of Doppler ultrasonography and their physiological background are initially presented, as well as haemodynamic parametres that can be used for evaluation of the findings. In sheep, Doppler ultrasonography has been used in clinical work primarily for examination of the reproductive system and of foetuses. It has also been used in studies, where sheep had served as model for studying various conditions in human physiology or medicine, e.g., examination of the heart, which can be performed by conventional Doppler echocardiography or tissue Doppler imaging. Main uses of the modality include evaluation of changes in follicular blood flow in measuring uterine and ovarian blood flow and for determining changes in blood perfusion during various reproductive stages; blood flows in the umbilical artery have also been measured, which can have a clinical application in identifying pregnancies at risk, as well as a model for human medicine. As technology advances, use of Doppler ultrasonography will increase. With more frequent use, new diagnostic and therapeutic approaches will arise, which would be based on estimating functional status (as evidenced by blood perfusion) of the organs examined. © 2016 Elsevier B.V