Hi,
Black Seagulls can not be created without AddOn, but for normal Seagulls you can use the attached script.
It creates two birds flying around in cricles and send them away after one minute.
I normally start it with a trigger named e.g. "Seagulls" put the trigger on a tree. Set a radius about 100m and start the script with [getPos Seagulls] exec "Birds.sqs".
Please add my name to the Readme if you use it. I will make an easier Version and release it.
If you have questions concerning this script, please send me a mail
Kuro