While February’s list of the 25 largest games on Facebook showed the end of a holiday traffic decline, this past month did not look quite so positive. A staggering 14 games, over half the chart, reported sizable losses in monthly active users. As a mater of fact, the minimum loss was 210,460 from none other than the mighty behemoth known as FarmVille. Yes, even the Zynga game that has grown month after month by millions of users experienced losses.

The question is as to whether or not this is a sign of things to come. Have people finally grown tired of virtual farming, for example? No, rather the likeliest cause was Facebook’s removal of third-party notifications, cutting off a communication channel that many developers relied on to keep users coming back.

Theorizing aside, this month did show a great deal of fluctuation across the list, and on a lighter note even hosted the debut of Ninja Saga as well as the return of two greater known titles.

Here are the highlights for the Top 25 Facebook Games for April, 2010:

• Zynga‘s mighty FarmVille experienced its first significant since its launch back in July of 2009. With still over 82.7 million monthly active users, however, a 200,000 user loss seems hardly significant. Next month’s stats might show more.
• RockYou‘s Birthday Cards took the hardest hit. Still coming in at #2, the app lost an incredible 7.2 million MAUs. Perhaps there just aren’t many birthdays in March.
• Mafia Wars inched its way back towards the top this month, overtaking CrowdStar‘s Happy Aquarium for the #5 spot with just over 25.3 million monthly active users. The aquatic virtual space game, however, loses over 2.3 million users, and drops to #6.
• RockYou’s exceedingly popular Zoo World lost nearly 1 million MAUs and dropped from #8 to #11. The game is still big, with 19.4 million monthly actives, but its decline has made room for MindJolt Games (gaining 2 million MAU), PetVille (gaining 1.4 million MAU), and Pet Society (gaining 441,828 MAU).
• PopCap’s Bejeweled Blitz moves up once again, tallying upwards of 10.5 million monthly active users to beat out Slashkey’s Farm Town for #15.
• Meanwhile CrowdStars other titles, Happy Island (11.7 million monthly active users) and Happy Pets (9 million monthly active users) sit tight at #14 and #17 respectively. Both, also experienced user losses of about 500,000 and 700,000 respectively.
• RockYou’s Hero World fell off the charts in March, but its decline made way for the appearance of the ninja role-playing app, Ninja Saga, which earns a total of 4,628,765 MAUs (check out our coverage from a few months ago for more on the game).
• Finally, behind the newcomer, TallTree Games and Playfish titles make to the Top 25 with Fish World and Country Story earning just over 4.3 and just under 4.3 million monthly active users respectively.