The second example is actually this:

package Bird;
use Dragonfly;
{
    package Dragonfly;
    sub divebomb { shift->SUPER::divebomb(@_)}
}
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If you look at your first example, you see that $self is set to the result of the shift function. shift returns the first value in an array (and removes it from the array), when it has no arguments it returns the first value from @_, which is also where you find the arguments of a sub.
Doing 'shift->SUPER::divebomb(@_)' does exactly the same thing, it's just a shortcut. (It calls shift, and then calls SUPER on the returned value of shift, missing out the step of assigning it to another variable.)

C.
PS: Your examples are a bit mixed up, $self->Donkey::speak(@_) is part of a third example in the middle of that page:

sub speak {
    my $self = shift;
    print "The mule speaks!\n";
    $self->Donkey::speak(@_);
}
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