For many years people thought that cat caught birds died of shock within 48 hours. It is only recently that rehabbers discovered that what they actually died of was pasteurella septicaemia. 90% of cats carry the pasteurella multocida bacteria in their saliva so the chances of infection are high and birds caught by cats will usually succumb to the septicaemia unless they are treated promptly with antibiotics
Because birds preen their feathers a cat caught bird can develop an infection from the pasteurella bacteria without suffering puncture wounds. The saliva on its feathers can pass into its system when it preens and it can develop pasteurellosis
The birds can die before symptoms of infection become noticeable, which is why rehabbers will treat birds that are even suspected of having been caught by a cat immediately with Clavamox (US) or Synulox (UK)
Birds that have been caught by hawks or dogs should be treated as for cat injuries.
Wounds should be flushed out with sterile saline, obtainable from the chemist (pharmacist)
It is best not to let a puncture wound scab over, as this seals infection in. Gentle removal of the scab, flushing with sterile saline and treating the area with an antibacterial cream will allow the wound to heal from within