Q:

Date When A Channel Field Was Added

Looking at the database, is there anyway to find out when a particular Channel field was added to EE?

A:

It doesn't look like it. The only field that could hold that data is the field_settings column, and that just has a few settings in an array that are serialized. 
Array
(
[tagger] => Array
(
[show_most_used] => yes
[single_field] => no
)

[field_show_smileys] => n
[field_show_glossary] => n
[field_show_spellcheck] => n
[field_show_formatting_btns] => n
[field_show_file_selector] => n
[field_show_writemode] => n
)

