If you need to check what is the output from every cron job (instead of see only when start and stop it in var/log/syslog)
you can append to your cron command this text:
2>&1 >> /var/log/myjob.log
and here you can see a working example:
rsync -avz /home/www/ /mnt/ububackup/SITE_BACKUP 2>&1 >> /var/log/backupUbu.log
This cron sync my www folder to another server and log the output to backupUbu.log .