Sometimes when I go on capture a wild pet I does not let me click on any catcher it only shows the observer, I have plenty of each capturures except for the magic catcher e.g...

i went on capture a wild pet and tried to click on reptile catcher of which I have x3 but the icon was grey and so was the rest of the catchers, only the observer was left

how are you supposed to capture a wild pet without any catchers?

Most likely you either don't have space in your stable, enough silver to buy them, or you ran out of licenses ( you can get more in the state store). Did that help?

i have 11 licences and when I did do capture a wild pet, I had 4 spaces available 

Lonewolf, you don't have free space in your stables. There's a line at the top of your Pets page which tells you your limit and how many spaces is taken already. You have 20/20 at this moment.

That's because i had some foals afterwards and I went to the pound.

( I wrote this fourm a day after the problem)

Baby pet takes the place in your stables at the moment when the mother becomes pregnant, so it's not possible to get over the limit simply by filling the stables with other pets while your females are in gestation. You didn't have free space in your stables because of this.