DSC_0102.NEF
DSC_0098.NEF
DSC_0103.NEF
DSC_0104.NEF
DSC_0101.NEF
Couldn't move DSC_0101.NEF: Operation not permitted at 2perl.pl line 30
...
...
DSC_0135.NEF
DSC_0136.NEF
Couldn't move DSC_0136.NEF: Operation not permitted at 2perl.pl line 30.
DSC_0137.NEF
...
...
##</code><code>##

use strict;
use warnings;
use 5.010;
use File::Find;
use File::Copy;

my $destination_dir = "/Users/me/Pictures/a b c d";

my $volume_name = "/Volumes/Volume\\ Name"; 
#need double slash in path for glob() in next line
#(see glob docs)

for (glob "$volume_name/*") {
    if (-d) {
        find(\&wanted, $_);
    }
}

sub wanted {
    if (-f && /\.NEF$/) {
        my $new_path = "$destination_dir/$_";
        say $_;
        move $_, $new_path or warn "Couldn't move $_: $!";  #**LINE 30***
    }
}