add_filter( 'genesis_nav_items', 'sws_social_icons', 10, 2 );
add_filter( 'wp_nav_menu_items', 'sws_social_icons', 10, 2 );

function sws_social_icons($menu, $args) {
    $args = (array)$args;
    if ( 'secondary' !== $args['theme_location'] )
        return $menu;
    ob_start();
    genesis_widget_area('social-menu');
    $social = ob_get_clean();
    return $menu . $social;
}