Gulp Babel Issue Using Foundation - gulp

Question

I'm using the latest version on Foundation 6.2 and have added Babel to the project. When I add new scripts to Concat and Uglify these don't work but in the Gulp file I comment out Babel the scripts work fine.
I've added my Gulp file below, babel is only needed for Foundations bower_compnents.
Any help would be very helpful.
Jemes
var gulp = require('gulp');
var $ = require('gulp-load-plugins')();
var sassPaths = [
'bower_components/foundation-sites/scss',
'bower_components/motion-ui/src'
];
// Sass
gulp.task('sass', function() {
return gulp.src('src/scss/app.scss')
.pipe($.sass({
includePaths: sassPaths,
outputStyle: 'compressed'
})
.on('error', $.sass.logError))
.pipe($.autoprefixer({
browsers: ['last 2 versions', 'ie >= 9']
}))
.pipe(gulp.dest('css'));
});
// Scripts
gulp.task('scripts', function() {
return gulp.src(['src/js/assets/jquery.js', 'bower_components/foundation-sites/dist/foundation.js', 'src/js/assets/jquery-scrolltofixed.js', 'src/js/assets/app.js'])
.pipe($.babel())
.pipe($.concat('app.js'))
.pipe(gulp.dest('src/js/built/'))
.pipe($.rename({ suffix: '.min' }))
.pipe($.uglify({mangle:false}))
.pipe(gulp.dest('js/'))
.pipe($.notify({ message: 'Scripts task complete' }));
});
// Default task
gulp.task('default', ['sass','scripts'], function() {
// Watch .scss files
gulp.watch('src/scss/**/*.scss', ['sass']);
// Watch .js files
gulp.watch('src/js/**/*.js', ['scripts']);
});