function my_exclude_wp_pages( $exclude_array ) {
	// array of ids you want to exclude
	$my_ids = array(1,2,3);

	// we merge the array from above to any existing page ids that may be excluded via other plugins
	$exclude_merge = array_merge( $my_ids, $exclude_array );

	return $exclude_merge;
}
add_filter( 'wp_list_pages_excludes', 'my_exclude_wp_pages' );