All animals will be frightened when they are not in their normal environment so take caution, for instance, wear gloves in case of scratches or nips. If you can't get the animal, try local rescue groups to see if they have a Have-A-Heart trap you could borrow. If you have a veterinarian, contact them to see if they will scan the animal for a microchip; if not, see if a local vet will perform the scan for you. Veterinarian offices would be the best first line source of information for rehoming and temporary care. After that, you can try adoption web sites to locate reputable rescue groups and shelters in our area. Use their search function along with your address/zip code to find those closest to your location and their contact information, and then start reaching out. Please note, shelters and rescues are constantly inundated so keep trying while being respectful of their situation. Consider fostering for one of them! Until you can place the animal, keep it separated from any pets you may have but keep it comfortable, fed, watered, and provided potty breaks and positive human interaction.
Try PetFinder.com, AdoptAPet.com, ASPCA.org, Best Friends Animal Society, PetSmart Charities, AKC Rescue Network. RescueMe.org has not only has countless pets up for adoption, but also has resources available for wildlife rehabilitators/shelters.