diff --git a/app/models/bulk_upload_data_set.rb b/app/models/bulk_upload_data_set.rb
index f1367c972..17a375a8d 100644
--- a/app/models/bulk_upload_data_set.rb
+++ b/app/models/bulk_upload_data_set.rb
@@ -1242,8 +1242,12 @@ def insert_data
           t.site_id = row['site_id']
 
           # Modify each Trait class instance so that date strings are
-          # interpreted as being in the time zone of the trait site
-          # (or UTC, if the trait site time_zone column is null)
+          # interpreted as being in the time zone of the trait site (or UTC, if
+          # the trait site time_zone column is null).  Note that in the Bulk
+          # Upload Wizard, the validation step will prevent reaching this code
+          # if a site without time zone is in the data file.  But nothing
+          # prevents a site without time zone from being specified
+          # interactively.
           class <<t
             def date=(value)
               date = Time.use_zone(Site.find(site_id).time_zone || 'UTC') do
@@ -1971,8 +1975,8 @@ def get_insertion_data
       # dates are assumed always to be accurate to the day:
       csv_row_as_hash["dateloc"] = 5
 
-      # bulk upload doesn't handles "date only" dates and dates with time to the
-      # second; determine which:
+      # bulk upload handles "date only" dates and dates with time to the
+      # second and no other cases; determine which:
       if csv_row_as_hash["date"].length == 19
         csv_row_as_hash["timeloc"] = 1
       elsif csv_row_as_hash["date"].length == 10
diff --git a/app/services/api_authentication_system.rb b/app/services/api_authentication_system.rb
index c044ee66c..a52974068 100644
--- a/app/services/api_authentication_system.rb
+++ b/app/services/api_authentication_system.rb
@@ -1,9 +1,14 @@
+# coding: utf-8
 module ApiAuthenticationSystem
   include AuthenticatedSystem
 
   # Override default access_denied action.
   def access_denied
-    @errors = "authentication failed"
+    if @errors
+      @errors = "authentication failed: " + @errors
+    else
+      @errors = "authentication failed"
+    end
     render status: 401
   end
 
@@ -19,4 +24,23 @@ def permissions(action_name, resource)
     end
   end
 
+  # Override "login_from_api_key" so that if no key is given or the given key is
+  # invalid, the user is logged in as the guest user.
+  def login_from_api_key
+    key = params[:key]
+    if key.nil?
+      u = User.find_by_login('guestuser')
+      if u.nil?
+        @errors = "For key-less access to the API, you must set up the guest user account."
+      end
+    else
+      u = User.find_by_apikey(key)
+      if u.nil?
+        @errors = "Invalid API key.  To access the API as a guest user, omit the “key” parameter."
+      end
+    end
+
+    return u
+  end
+
 end