There's no bird files, they're completly hard coded with textures taken from the clouds texture file.
I know the video isn't yours, but there's nothing strange with the bird (at all), it's just him in his natural habitat
If you'd like to customize the birds, use this plugin-tool. I'd like to make 'em in 3D for now, but...
The tool link: http://gtaforums.com...e-birds-update/
GTAF BBCode is being problematic these days.
- Gray Wolf likes this