Who takes gulls
No organisation in this directory is recorded as naming gulls specifically. Rather than show an empty page, this lists the 12 recorded as taking wildlife more broadly — which is where an injured one would go. It is not a statement that any of them takes gulls.
Capacity is shown only where an organisation confirmed it, with how long ago. If you run one of these and the species are wrong, that is exactly the kind of correction the site wants — tell us and the listing gains a species rather than a guess.