diff --git a/lib/jekyll/drops/collection_drop.rb b/lib/jekyll/drops/collection_drop.rb
index 2c447cb4..8dc8c6b8 100644
--- a/lib/jekyll/drops/collection_drop.rb
+++ b/lib/jekyll/drops/collection_drop.rb
@@ -6,7 +6,12 @@ module Jekyll
     class CollectionDrop < ImmutableDrop
       extend Forwardable
 
-      def_delegators :@obj, :label, :docs, :files, :directory, :relative_directory
+      def_delegators :@obj, :label, :docs, :files, :directory,
+                            :relative_directory
+
+      def to_s
+        @obj.docs.map(&:to_s).join(' ')
+      end
 
       def output
         @obj.write?