One advantage of high megapixel sensors for bird photos is that you can significantly crop an image and still have decent resolution in the crop for printing. I can crop a smaller section of an 18 megapixel image and print it than I could with my old 8 megapixel images. I've found that cropping the same small portion of an 8 megapixel image will sometimes fail pixelation limits for prints (i.e., a small crop of an 8 megapixel image will sometimes have too few pixels to print without pixelation).
You’re both correct; bigger megapixels do lend themselves to cropping. Again, it all goes back to the specifics of how you want to use the photo.
Professional photographers should always have the option to crop, especially if they use high-end DSLR equipment that balances ISO and resolution due to using a larger sensor. My complaint isn’t about resolution per se, it’s a complaint about resolution vs. sensitivity. The average consumer believes that a 15 MP camera is automatically better than a 10 MP camera, even though the 10 MP camera may make consistently better quality images in most lighting situations. Not so much with DSLRs, that have larger sensors and can handle higher ISOs.
It makes it hard to find a decent all-around camera unless you want to carry around a clunky DSLR all the time.
And many people, especially those using point-and-shoot, they’re not as worried about composition...they just want a pouty picture of themselves to use as their Facebook signature.
Of course, I’m talking about point-and-shoot, consumer-grade cameras in general. There’s no real need for them to have 14+ megapixels when most people are simply viewing their pictures online or making 4x6 prints.