Here are the resources that I use to post my sightings:
Comalbirders: http://groups.yahoo.com/group/comalbirds/ (membership required to read and/or post)
San Antonio Audubon: http://groups.yahoo.com/group/SATXbirds/?yguid=298178119 (membership required to read and/or post)
Texbirds: https://www.freelists.org/list/texbirds (membership required to post or respond; public viewing of posts)
Comal County Birders: https://www.facebook.com/groups/1783494555253483/
eBird: http://ebird.org/content/ebird/ a site for posting location specific observations, in a public or private format; keep lifelists; view and analyze submitted data, etc.
This site was last updated 10/22/17