amazon ec2 - EC2 instance sends mail for every succesful or failed cron job - how to stop that?

We receive hundreds of mails every day from the cron deamon to root@company.com. How can I stop that? Those mails refer to custom cron jobs set up by us - as well as others set up by AWS.

The mail subject looks as follows:

Cron  [ -x /usr/share/awstats/tools/update.sh ] && /usr/share/awstats/tools/date.sh

I read this is default behavior but I can't find a way to switch it off.

Neither crontab -l nor sudo crontab -l contains a MAILTO directive or anything other than regular cron job timings.

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> cat vim /etc/crontab    cat: vim: No such file or directory
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'

# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# m h dom mon dow user  command
17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )

47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )