DB Manager can't connect to PostgreSQL, but "Add PostGIS Layer" can.

My eventual goal is to save created layers or imported files to PostGIS. I assume I can do this using the DBManager Tool. I can alternatively use ogr2ogr or shp2pgsql, but I was hoping QGIS would make workflows between shapefiles and PostGIS a bit easier.

This behavior seems odd. Why can it connect one way and not the other?

I can connect easily with psql on command line

Additional Info:

• This is a local database
• When I originally connected using 'Add PostGIS Layer', I chose not to save the username and password. I am connecting using my OS user account.
• I'm running OS X 10.9.2, PostGIS 2.1, PostgreSQL 9.3.3, and QGIS 2.2.0
• PostgreSQL, PostGIS and QGIS were all installed using Homebrew. See Homebrew install info below.

Homebrew info:

brew info qgis-22
qgis-22: stable 2.2.0, HEAD
http://www.qgis.org
/usr/local/Cellar/qgis-22/2.2.0 (14074 files, 493M) *
  Built from source with: --with-grass, --with-api-docs, --with-postgis
From: https://github.com/dakcarto/homebrew-osgeo4mac/commits/master/Formula/qgis-22.rb
==> Dependencies
Build: cmake ✔, bison ✔
Required: qt ✔, pyqt ✔, qscintilla2 ✔, qwt ✔, qwtpolar ✔, gsl ✔, sqlite ✔, expat ✔, proj ✔, spatialindex ✔, fcgi ✔, gdal ✔, pyspatialite ✔
Recommended: postgresql ✔, gpsbabel ✔
Optional: postgis ✔, grass ✔, qt-mysql ✘, orfeo ✘, r ✘, saga-gis ✘

brew info postgis
postgis: stable 2.1.1, HEAD
http://postgis.net
/usr/local/Cellar/postgis/2.1.1 (44 files, 8.3M) *
  Built from source
From: https://github.com/Homebrew/homebrew/commits/master/Library/Formula/postgis.rb
==> Dependencies
Build: autoconf ✔, automake ✔, libtool ✔, gpp ✔
Required: postgresql ✔, proj ✔, geos ✔, json-c ✔, gdal ✔

brew info postgresql
postgresql: stable 9.3.3 (bottled)
http://www.postgresql.org/
Conflicts with: postgres-xc
/usr/local/Cellar/postgresql/9.3.2 (2968 files, 66M)
  Poured from bottle
/usr/local/Cellar/postgresql/9.3.3 (2967 files, 65M) *
  Poured from bottle
From: https://github.com/Homebrew/homebrew/commits/master/Library/Formula/postgresql.rb
==> Dependencies
Required: readline ✔
Recommended: ossp-uuid ✔