Many social games saw traffic stagnate or fall in December due to the usual holiday decline, if not new Facebook platform policy changes. This past month has seen some recovery.

Zynga continues to hold the top position with FarmVille; that game has managed to continue growing in the past month to reach a whopping 75.5 million monthly active users (MAU), far more than any rival.

Meanwhile, CrowdStar has solidified its place on this list with three titles. RockYou has been having something of a resurgence from its earlier days building simple apps — although one Birthday Cards, is still a pretty simple app, Zoo World is a game and it’s been doing quite well.

Here are the highlights of this past month’s Top 25 Facebook Games:

• Zynga‘s FarmVille garnered more than 1.5 million new monthly active users (MAUs) with younger title, Café World coming in a distant third with just over 30 million MAUs (compared to FarmVille’s 75+ million).
• As with last month, Birthday Cards from RockYou has climbed up the charts,and it comes in at a decent second with over 40 million monthly actives. However, the app is mostly for virtual card giving. The part of it that’s a game is a window you can access to play Zoo World — an actual game that separately made our list today.
• Crowdstar rose to prominence last fall with virtual fish-caring game Happy Aquarium. That title comes in at #4 with over 25 million monthly active users. The developer’s other titles on the list include Happy Pets at #16 (down from #14 last month) and Happy Island at #17 (up from #25).
• Mafia Wars continues to decline in popularity, as of late — relatively speaking. It has droppped down to #7 from #6, tallying in at 24,398,295 MAUs.
• Also, Playfish‘s Pet Society and Zynga’s PetVille vie for the cute animal avatar position at #8 and #9 respectively. Currently, their MAU difference is roughly 1 million.
• Speaking of animals, zoo- keeping seems to be growing as RockYou’s Zoo World shoots from #16 to #10 with 16,206,134 monthly actives.
• Digital Facebook pillow fighting proves to be oddly popular as the new comer to last month’s list, Pillow Fight, appears yet again, but this time up four spots, coming in at #14. Like Birthday Cards, this app is not actually a game, and only gets counted as such because the developer marked it in the “Games” category on Facebook.
• Rounding out the list comes the return of Bumper Sticker at #22 (6,640519 MAUs), new Playdom title Tiki Farm at #23 (6,143,715 MAUs), Sorority Life at #24 (6,111,378 MAUs), and Fish World at #25 (6,107,978 MAUs).