It may not be quite what's wanted but if you use 
my $chicago = { qw(tiger bob munch toy) };
my $wisconsin = { qw(tiger sara munch toy) };
my $rockford = { qw(tiger sara love toy) };
...
my $newIntersection = &intersection($chicago,$wisconsin,$rockford);

OUTPUT
tiger - only common key in all 3 hashes

Also 
my $chicago = { qw(tiger 0 bob 0 munch 0 toy 0 ) };
my $wisconsin = { qw(tiger 0 sara 0 munch 0 toy 0 ) };
my $rockford = { qw(tiger 0 sara 0 love 0 toy 0 ) };

OUTPUT
tiger toy - common keys in all 3 new hashes.

[download]
We don't keep the values though. key => undef.

The hash reference define I found somewhere else on this site but I can't remember where.

In reply to Re: Syntax Error using STRICT and Declaring Variable by tweetiepooh
in thread Syntax Error using STRICT and Declaring Variable by awohld

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