Classic column themes?

Cecil's Columns/Staff Reports
1

Are the classic column revisits intentionally staying in the same themes? First, cats, now pigeons:

http://www.straightdope.com/classics/a1_015b.html
http://www.straightdope.com/classics/a1_015a.html
http://www.straightdope.com/classics/a1_016.html

Not that I mind, I was just curious if this was intentional or coincidental. (And yes, I know that one about squirrels climbed in, but what’s a squirrel but a wingless, tree-climbing pigeon?)

2

We notice that the dates are not consecutive. But from the URLs we see they are being mentioned in the order in which they are presented in the first Straight Dope book. So one would assume that the columns were categorized when included in the book, and if one presents old columns in the same order as included in the book, then we will have columns on similar subjects being featured consecutively on the home page.