diff --git a/pelican/generators.py b/pelican/generators.py
index 75eca388..ef021070 100644
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -155,16 +155,15 @@ class Generator(object):
 
             if os.path.isdir(root):
                 for dirpath, dirs, temp_files in os.walk(
-                        root, followlinks=True):
-                    drop = []
+                        root, topdown=True, followlinks=True):
                     excl = exclusions_by_dirpath.get(dirpath, ())
-                    for d in dirs:
+                    # We copy the `dirs` list as we will modify it in the loop:
+                    for d in list(dirs):
                         if (d in excl or
                             any(fnmatch.fnmatch(d, ignore)
                                 for ignore in ignores)):
-                            drop.append(d)
-                    for d in drop:
-                        dirs.remove(d)
+                            if d in dirs:
+                                dirs.remove(d)
 
                     reldir = os.path.relpath(dirpath, self.path)
                     for f in temp_files:
diff --git a/pelican/tests/support.py b/pelican/tests/support.py
index 93db8328..751fb5ec 100644
--- a/pelican/tests/support.py
+++ b/pelican/tests/support.py
@@ -188,7 +188,7 @@ class LogCountHandler(BufferingHandler):
     """Capturing and counting logged messages."""
 
     def __init__(self, capacity=1000):
-        logging.handlers.BufferingHandler.__init__(self, capacity)
+        super(LogCountHandler, self).__init__(capacity)
 
     def count_logs(self, msg=None, level=None):
         return len([