diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 9f3169a4b..16652c8f7 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -227,6 +227,9 @@ class ApplicationController < ActionController::Base
   end
   
   def invalid_authenticity_token
+    if api_request?
+      logger.error "Form authenticity token is missing or is invalid. API calls must include a proper Content-type header (text/xml or text/json)."
+    end
     render_error "Invalid form authenticity token."
   end
   
@@ -308,4 +311,8 @@ class ApplicationController < ActionController::Base
   def filename_for_content_disposition(name)
     request.env['HTTP_USER_AGENT'] =~ %r{MSIE} ? ERB::Util.url_encode(name) : name
   end
+  
+  def api_request?
+    %w(xml json).include? params[:format]
+  end
 end