They are probably looking for water. Put shallow pan out located a distance away from the tomatoes and hopefully that will keep them from taking a bite or two from your tomatoes.
I will say this, if ya live near Katy Texas these 2 old guys on Dahlia Lane competed back yard to back yard, and sold (may even still sell) great family fresh corn, tomatoes, what ever from the front driveway. I wish i had their growing skills.
Yes, I like less regulations.
Thanks for the tip...I will try that :)