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Authors: Adiv Gal, David Saltz, and Uzi Motro

The effect of food supplement to Lesser Kestrel (Falco naumanni) nests during the nestling period (from hatching to fledging) was studied in two nesting colonies in Israel – Alona and Jerusalem. Our hypothesis, based on diminishing returns considerations, was that food supplement will have a greater effect on fledgling success in the food-limited, urban colony of Jerusalem, than in the rural colony of Alona. Indeed, food supplement had a significantly positive effect on breeding success in both colonies. However, and contrary to our prediction, the decrease in chick mortality between supplemented and control nests in Jerusalem was not larger than in Alona (actually it was numerically smaller, albeit not significantly so). This implies either that additional factors, possibly urbanization associated, other than food limitation, might be responsible for the difference in nesting success of Lesser Kestrels between Alona and Jerusalem, and/or that the amount or the nutritional quality of the additional food provided to supplemented nests (three mice per chick per week), was not enough.

In: Israel Journal of Ecology and Evolution

We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.

In: Israel Journal of Ecology and Evolution

A computerized image analysis package (ImagePro+) was evaluated as an alternative method for morphometric analysis of electron micrographs of microalgal cells. The morphometric analysis was demonstrated with micrographs of the marine alga Nannochloropsis sp. grown under high and low light intensity. We applied the ImagePro+ package to estimate the relative volume of an organelle based on the ratio of perimeters of the organelle and the cell. The measurements included the volumes of chloroplasts, mitochondria, nuclei, vacuoles, and accumulation bodies, all relative to cell volume. The length of thylakoids was measured using the same package.

The results obtained by ImagePro+ were compared to those of the traditional manual and laborious method involving the superimposition of an array of short lines on the micrograph. A high correlation between the methods was found. The following correlations were found for chloroplast, nucleus, and accumulation bodies: 0.96, 0.92, and 0.75, respectively. The correlation between length of thylakoids (ImagePro+) and surface area of thylakoids (superimposition) was 0.82.

In: Israel Journal of Plant Sciences