--- dateutil/zoneinfo/__init__.py
+++ dateutil/zoneinfo/__init__.py
@@ -14,9 +14,10 @@

 __all__ = ["setcachesize", "gettz", "rebuild"]

-_ZONEFILENAME = "dateutil-zoneinfo.tar.gz"
+_LOCAL_ZONEINFO_FILE = "dateutil-zoneinfo.tar.gz"
+_SYSTEM_ZONEINFO_DIR = "/usr/share/zoneinfo"

-# python2.6 compatability. Note that TarFile.__exit__ != TarFile.close, but
+# python2.6 compatibility. Note that TarFile.__exit__ != TarFile.close, but
 # it's close enough for python2.6
 _tar_open = TarFile.open
 if not hasattr(TarFile, '__exit__'):
@@ -31,9 +32,8 @@

 def getzoneinfofile_stream():
     try:
-        return BytesIO(get_data(__name__, _ZONEFILENAME))
+        return BytesIO(get_data(__name__, _LOCAL_ZONEINFO_FILE))
     except IOError as e:  # TODO  switch to FileNotFoundError?
-        warnings.warn("I/O error({0}): {1}".format(e.errno, e.strerror))
         return None


@@ -59,6 +59,14 @@
                 self.zones.update(links)
         else:
             self.zones = dict()
+            if os.path.isdir(_SYSTEM_ZONEINFO_DIR):
+                for root, dirnames, filenames in os.walk(_SYSTEM_ZONEINFO_DIR):
+                    for filename in filenames:
+                        absolute_filename = os.path.join(root, filename)
+                        relative_filename = absolute_filename[len(_SYSTEM_ZONEINFO_DIR)+1:]
+                        with open(absolute_filename, "rb") as file:
+                            if file.read(4) == b"TZif":
+                                self.zones[relative_filename] = tzfile(absolute_filename, relative_filename)


 # The current API has gettz as a module function, although in fact it taps into
@@ -99,7 +107,7 @@
                         "libc-bin or some other package that provides it, "
                         "or it's not in your PATH?")
                     raise
-        target = os.path.join(moduledir, _ZONEFILENAME)
+        target = os.path.join(moduledir, _LOCAL_ZONEINFO_FILE)
         with _tar_open(target, "w:%s" % format) as tf:
             for entry in os.listdir(zonedir):
                 entrypath = os.path.join(zonedir, entry)