Unexpected Token < in Flickr HTML

$(document).ready(function() {
  $('button').click(function() {
    $("button").removeClass("selected");
    $(this).addClass("selected");
    var flickrAPI = "http://api.fickr.com/services/feeds/photos_public.gne?jsoncallback=?";
    var animal = $(this).text(); // gets text in an HTML element
    var flickrOptions = {
      tags: animal,
      format: "json"
    };
    function displayPhotos(data) {
      var photoHTML = '<ul>';
      $.each(data.items, function(i, photo) {
        photoHTML += '<li class="grid-25 tablet-grid-50">';
        photoHTML += '<a href="' + photo.link + '" class="image">';
        photoHTML += '<img src="' + photo.media.m + '"></a></li>';
      });
      photoHTML += '</ul>';
      $('#photos').html(photoHTML);
    }
    $.getJSON(flickrAPI, flickrOptions, displayPhotos);
  });
 });