HI Andrea, I am very sorry to hear that your little mocker did not survive the night. I wish we had been able to get back to you sooner. The economic crisis has taken its toll on wildlife and has left small, independent organizations like us without funds or adequate help. As such, we are struggling to meet the demands of the season and to effectively handle the call load.
I do want you to know that your baby should have been able to survive that period of time without a problem even though you were not able to get treatment for him right away. It is likely that the injury you saw was a fatal one. If cat caught, birds usually die within the first 24 hours and there is nothing that can be done except to keep comfortable to prevent further suffering. You were able to accomplish that and , sadly, it is sometimes the best that can be done. Internal injuries cannot be treated nor can they be detected. Because the baby died within that short period, I am guessing that some internal injuries had to be present. Nevertheless, it is heart wrenching to see the baby succumb and we share your grief and disappointment.
I hope you will not be discouraged by this event. Rest assured that you did the right thing and you made this bird's last moments warm and comfortable. The kindness of people like you make the world a better place. Thank you for all you did! Please keep the attached rescuer response / instruction on hand for your next rescue (it happens). Hopefully, it will help you in the future.