You should know how to introduce a kitten to a cat before you bring any new kitten to meet with your resident adult cat. That is why; it is better for you to prepare everything beforehand so it can be done smoothly as you want.
If you do not do enough preparation, then most of the time, it will result in the cats being scared and they may also feel threaten.
You should be careful as when a cat is already having this kind of feel about the other cat. Then it will be very difficult for you to change how they feel about them later on.
Learn How to Introduce a Kitten to a Cat
Cat has different social behavior as other type of pet such as dog. Even though they can make friends with other cat, but they do not feel any need of having other cat in the house. Thus they will be more than happy if they are the one and only cat in your resident.
However, do not be afraid as it does not mean they cannot accept any cat being around. The only thing that you need to ensure is there should be no competition between the two cats especially for litter tray, sleep area, as well as their food. With that, they will be able to accept each other presence and might even bonded.
Before introducing a new cat to older cat, it is better to do it slowly. Separate your new cat by making a new area for her in your house at first.
Then put everything that your cat need in that area. Put the kitten inside large crate used for dog but open the door so she can explore the area once she feels secure enough to leave the crate.
Introduce your kitten to your cat by using their smell. Try to exchange both of their bedding so your cat can smell the kitten smell through it. This will make your cat feel comfortable and familiar to the kitten smell thus will make it feel less threatening.
Another method to do is by stroking your kitten using your hand and not washing it then uses it to stroke the other cat.
Try to take a cloth then use it to stroke the kitten cheek as well as the head, and then rub this cloth to your furniture to mix her smell into your furniture.
The initial introduction should use stair gates as barrier so they would not hurt each other in the process. Pick a neutral room or put the crate with the door closed, and then put them in that room with food used to distract them from being threaten.
Remember that they should be able to freely go back to their own safe place if they feel like to. Leave them and do not force them to meet, they will eventually try to get closer and sniff through the barrier. Do this method regularly but ensure there is a break in between to not give them too much pressure.