Various insects and arachnids reside around the Petitcodiac River. Among them is the stonefly, the mayfly, the caddisfly, the "simulium", the subfamily of tanypodinae, and the Hydracarina. Non-native species, such as the black-footed spider, the beech scale, the white-marked tussock moth, and the mountain ash sawfly have also made their home in the Petitcodiac River watershed. At the southern extremities of the watershed, 50 to 90 percent of the world's semipalmated sandpipers feed on the mud shrimp at Shepody Bay. Around 269,445 stop there before migrating to South America, a number which accounts for at least 7.7 percent of the total population. Among others, the semipalmated plover (around 2 percent of the North American population), the short-billed dowitcher, the red knot, the sanderling, and the least sandpiper are also known for migrating through the Important Bird Area.