A raccoon knocking over trash cans at 2 a.m. A line of carpenter ants marching across the kitchen counter. A weird scratching sound coming from the attic that nobody wants to investigate. For Long Island homeowners, these scenarios aren’t hypothetical. They’re Tuesday.

Pest and wildlife problems tend to follow predictable patterns on Long Island, driven by the region’s climate, housing density, and proximity to water. Understanding which animals and insects are most likely to show up, and why, is the first step toward keeping them out for good.…