Is it squirrels or raccoons in my attic?

Gray squirrels are diurnal and chew their way in, gnawing siding and the wood under the eaves to make openings, or pushing through loose siding and vent screens (Penn State). They breed twice a year, in mid-December to early January and again in June, with one to eight pups per litter (Penn State), so late winter and early summer are when females are most determined to get into an attic. Once inside they damage walls, insulation, and the insulation around electrical wires, which is a fire hazard (Penn State). Outside, look for a chewed hole about 2 inches across at the roofline, fascia, or gable vent.

Raccoons are nocturnal, average about 15 pounds, and don't chew their way in; they pull. Torn soffit panels, bent vent covers, and a pushed-in attic vent with muddy paw prints on the siding are raccoon work. Females look for den sites in late winter and have litters of one to seven in April and May, staying with the young until September or October (NYSDEC). Raccoon rabies has been widespread in New York since 1990 (NYSDEC), and their droppings carry roundworm, so an attic they've used is a cleanup job as well as a removal.

NYSDEC's guidance is to never permanently seal an entrance without confirming every animal is out. Seal a mother out in spring and the young die in the wall; seal an adult in and it chews a new hole. New York also requires a licensed nuisance wildlife control operator for trapping and removing problem raccoons (NYSDEC). Removal first, confirmation that nothing is left, then sealing with heavy 1/2 inch wire mesh, and trimming tree limbs 6 to 8 feet back from the roof so they can't jump on (Penn State).

Wooded lots on the North Shore and the properties bordering preserves and parks in places like Glen Cove, Locust Valley, Bethpage, and Huntington get the most attic calls, and older homes with original soffits and roof returns are the easiest to get into. Fall and late winter are the two rushes.