var windowWidth = $(window).width(),
        $mainNav = $('nav.main-navigation');

    if (windowWidth <= 480) {

        var options = '',
            $select = $('<select class="menu"></select>');

        $mainNav
            .find('a').each(function(){
                var href = $(this).attr('href'),
                    text = $(this).text();
                options += '<option value="'+ href +'">'+ text +'</option>';
            })

        $('<select class="menu"></select>')
            .append(options)
            .find('<option>')
            .click(function(){ location = $(this).val(); })
            .end()
            .appendTo($mainNav);
    }