Securities And Exchange Commission
                             Washington, D.C. 20549

                                  Schedule 13G

                    Under the Securities Exchange Act of 1934

                                 Amendment No. 5

                           Southwestern Energy Company
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    845467109
--------------------------------------------------------------------------------
                                 (CUSIP Number)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[x] Rule 13d-1 ( b)
[ ] Rule 13d-1 ( c)
[ ] Rule 13d-1 ( d)


The  remainder  of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures  provided in a prior cover page. The information in the remainder of
this cover page shall not be deemed to be "filed"  for the purpose of Section 18
of the Securities  and Exchange Act of 1934 ("Act") or otherwise  subject to the
liabilities  of that  section  of the Act but  shall  be  subject  to all  other
provisions of the Act (however, see the Notes).


                                      13G

CUSIP No. 845467109
-------------------------------------------------------------------------------
1   Name of Reporting Person
    S.S. OR I.R.S. Identification No. of Above Person
    Westport Asset Management, Inc. - 06-1087640
    Westport Advisers LLC - 06-1497709

-------------------------------------------------------------------------------
2   Check the appropriate box if a member of a group*
                                                                        (a) |_|
                                                                        (b) |X|
-------------------------------------------------------------------------------
3   SEC Use only


-------------------------------------------------------------------------------
4   Citizenship or place of organization
    Connecticut

-------------------------------------------------------------------------------
                  5    Sole Voting Power
                       0
                  -------------------------------------------------------------
Number of         6    Shared Voting Power
Shares                 538,900
Beneficially      -------------------------------------------------------------
Owned             7    Sole Dispositive Power
By Each                0
Reporting         -------------------------------------------------------------
Person            8    Shared Dispositive Power
With                   752,900
-------------------------------------------------------------------------------
9   Aggregate Amount Beneficially Owned by Each Reporting Person
    752,900

-------------------------------------------------------------------------------
10  Check box if the aggregate amount in row (9) excludes certain shares
    ---
                                                                            |x|
-------------------------------------------------------------------------------
11  Percent of Class Represented by Amount in Row 9
    2.11%

-------------------------------------------------------------------------------
12  Type of Reporting Person*
    IA

-------------------------------------------------------------------------------



Item 1 (a)      Name of Issuer:
-----------     ---------------
                SOUTHWESTERN ENERGY COMPANY

Item 1 (b):     Address of Issuer's Principal Executive Offices:
-----------     ------------------------------------------------
                2350 W. SAM HOUSTON PKWAY E., SUITE 300
                HOUSTON, TX 77032-1408

Item 2 (a):     Name of Person Filing:
-----------     ----------------------
                WESTPORT ASSET MANAGEMENT, INC.

Item 2 (b):     Address of Principal Business Office:
-----------     -------------------------------------
                253 Riverside Avenue
                Westport, CT  06880

Item 2(c):      Citizenship:
-----------     ------------
                Connecticut

Item 2(d):      Title of Class of Securities:
-----------     -----------------------------
                Common Stock

Item 2 (e):     CUSIP Number:
-----------     -------------
                845467109

Item 3.         If this stated is filed pursuant to Rules 13d-1(b), or
-------         13d-2(b), check whether the person filing is a:
                ---------------------------------------------------------------


                (a) ( ) Broker or Dealer registered under Section 15 of the Act

                (b) ( ) Bank as defined in Section 3(b)(6) of the Act

                (c) ( ) Insurance Company as defined in Section 3(a) (19) of
                        the Act




                (d) ( ) Investment Company registered under Section 8 of the
                        Investment Company Act

                (e) (X) Investment Adviser registered under Section 203 of the
                        Investment Advisors Act of 1940

                (f) ( ) Employee Benefit Plan, Pension Fund which is subject
                        to the Provisions of the Employee Retirement Income
                        Security Act of 1974 or Endowment Fund; see ss.240.13d-1
                        (b)(1)(ii)(F)

                (g) (X) Parent Holding Company, in accor- dance with
                        ss.240.13d-1(b)(ii)(G) (Note: See Item 7)

                (h) ( ) Group in accordance with ss.240.13d-1 (b)(1)(ii)(H)

Item 4.         Ownership.
-------         ---------

                (a)  Amount  Beneficially  owned:
                     752,900 shares

                (b)  Percent of Class:
                     2.11%

                (c)  Number of shares as to which such person has:

                     (i)  sole power to vote or to direct the vote:
                          0

                     (ii) shared power to vote or to direct the vote:
                          538,900

                     (iii)sole power to dispose or to direct the disposition
                          of: 0

                     (iv) shared power to dispose or to direct the disposition
                          of:
                          752,900





Item 5.         Ownership of Five Percent or Less of a Class
-------
                If this statement is being filed to report the fact that as of
the date hereof the reporting person has ceased to be the beneficial owner of
more than five percent of the class of securities, check the following ( X )

Item 6.         Ownership of More than Five Percent on Behalf of Another Person:
-------         N/A




Item 7.         Identification and Classification of the Subsidiary
-------         Which acquired the Security Being Reported on By the
                Parent Holding Company.

WESTPORT ASSET MANAGEMENT,INC. MAKES THIS FILING PURSUANT TO RULE 13D-1 (B)
(II) (G) SINCE IT OWNS 50% OF WESTPORT ADVISERS LLC. WESTPORT ASSET MANAGEMENT,
INC. IS AN INVESTMENT ADVISOR AND WESTPORT ADVISORS LLC IS AN INVESTMENT
ADVISOR FOR A SERIES OF PUBLIC MUTUAL FUNDS.



Item 8.         Identification and Classification of Members of the Group.
-------         N/A

Item 9.         Notice of Dissolution of Group.
-------         N/A


Item 10.        Certification

                By signing below, I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired in the ordinary
course of business and were not acquired for the purpose of and do not have the
effect of changing or influencing the control of the issuer of such securities
and were not acquired in connection with or as a participant in any transaction
having such purpose or effect.

                Disclaimer

                The undersigned expressly declares that the filing of this
Schedule 13G shall not be construed as an admission that such person is, for the
purpose of Section 13(d) or 13(g) of the Securities Act of 1934, the beneficial
owner of any securities covered by this statement.

                Signature. After reasonable inquiry and to the best of my
                knowledge and belief, I certify that the information set forth
                in this statement is true, complete and correct.

Date     February 12, 2004


                                           Westport Asset Management, Inc.

                                           By /s/ Andrew J. Knuth
                                           -------------------------------
                                           Andrew J. Knuth, Chairman