diff --git a/django/middleware/common.py b/django/middleware/common.py
index 689929bea4..fb55412c9b 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -130,7 +130,7 @@ def _is_ignorable_404(uri):
     if getattr(settings, 'IGNORABLE_404_STARTS', ()):
         import warnings
         warnings.warn('The IGNORABLE_404_STARTS setting has been deprecated '
-                      'in favour of IGNORABLE_404_URLS.',
+                      'in favor of IGNORABLE_404_URLS.',
                       PendingDeprecationWarning)
         for start in settings.IGNORABLE_404_STARTS:
             if uri.startswith(start):
@@ -138,7 +138,7 @@ def _is_ignorable_404(uri):
     if getattr(settings, 'IGNORABLE_404_ENDS', ()):
         import warnings
         warnings.warn('The IGNORABLE_404_ENDS setting has been deprecated '
-                      'in favour of IGNORABLE_404_URLS.',
+                      'in favor of IGNORABLE_404_URLS.',
                       PendingDeprecationWarning)
         for end in settings.IGNORABLE_404_ENDS:
             if uri.endswith(end):
diff --git a/docs/howto/error-reporting.txt b/docs/howto/error-reporting.txt
index 4642c39a92..c15c1d872d 100644
--- a/docs/howto/error-reporting.txt
+++ b/docs/howto/error-reporting.txt
@@ -84,10 +84,12 @@ crawlers often request::
     import re
     IGNORABLE_404_URLS = (
         re.compile(r'^/apple-touch-icon.*\.png$'),
-        re.compile(r'^/favicon.ico$),
-        re.compile(r'^/robots.txt$),
+        re.compile(r'^/favicon\.ico$),
+        re.compile(r'^/robots\.txt$),
     )
 
+(Note that these are regular expressions, so we put a backslash in front of
+periods to escape them.)
 
 The best way to disable this behavior is to set
 :setting:`SEND_BROKEN_LINK_EMAILS` to ``False``.