The Northwestern Naturalist (new series).
With two (formerly three)  issues published each year, this publication carries original articles, items of news and general interest, together with information on courses, book reviews, etc.
A special feature is its diary of the meetings and field outings of affiliated societies which is intended to encourage wide participation in those activities. Individual members receive a free copy of each issue.
Contents of back copies are being made available on line over time via the links below.
The list of articles in past issues is here

Volume 1 No. 1 1999
Volume 1 No. 2 1999
Volume 1 No. 3 2000
Volume 2 No. 3 2000
Volume 2 No. 2 2000
Volume 2 No. 3 2001
Volume 3 No. 1 2001
Volume 3 No. 2 2001
Volume 3 No. 3 2002
Volume 4 No. 1 2002
Volume 4 No. 2 2002
Volume 4 No. 3 2003
Volume 5 No. 1 2003
Volume 5 No. 2 2003
Volume 5 No. 3 2004
Volume 6 No. 1 2004
Volume 6 No. 2 2004
Volume 6 No. 3 2005
(In progress)