my's argument must be a variable name, or a list of variables in parens.
@chicago{   qw(tiger bob munch toy)    }
is neither. I'm afraid you'll have to do

my %chicago;   @chicago{   qw( tiger bob munch toy  ) } = ();
my %wisconsin; @wisconsin{ qw( tiger sara munch toy ) } = ();
my %rockford;  @rockford{  qw( tiger sara love toy  ) } = ();
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or

my %chicago   = map { $_ => undef } qw( tiger bob munch toy  );
my %wisconsin = map { $_ => undef } qw( tiger sara munch toy );
my %rockford  = map { $_ => undef } qw( tiger sara love toy  );
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or even better (since you won't have to use exists)

my %chicago   = map { $_ => 1 } qw( tiger bob munch toy  );
my %wisconsin = map { $_ => 1 } qw( tiger sara munch toy );
my %rockford  = map { $_ => 1 } qw( tiger sara love toy  );
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