Johnson's Mills
Coordinates: Lat 45.836162°N, Long 64.514834°W
Description and directions: A rocky and sandy beach with extensive mud flats not far from Dorchester, situated six kilometers south of the village along route 935. Besides having an awesome view of Shepody Bay, it is one of just a handful of sites in the Upper Bay of Fundy used as important migratory stopovers for up to 85% of the world population of a small, arctic nesting shorebird known as the Semipalmated Sandpiper. These birds come to the Fundy Biosphere Region and surrounding areas as a stopover on their migratory route, and during their visit they usually double their weight from 20g to 40g by feeding primarily on mudshrimp.
Nature Notes: This 472-acre site (to date) is managed by the Nature Conservancy of Canada. From late July to mid-August, tens of thousands of shorebirds can be seen here daily, both feeding on the mudflats that are exposed at low tide, then roosting in tight flocks on the upper beach when the world’s highest tides come in.
The twice daily high tide periods (2-4 hours a day) are the only time in the 24-hour cycle that the birds get to rest. It is therefore the time when they are at their most vulnerable from opportunistic predators, such as Peregrine Falcons, Merlins, other hawks and gulls. Therefore, in as much as possible, they should be left undisturbed by people and their pets. When roosting, the birds occasionally harassed by natural predators lift up in tremendous flocks which wheel and twist, performing an intricate and beautiful aerial ballet to our eyes, but which is actually an instinctual response to danger that apparently aids to confuse aerial predators and lessen the chance of individual predation. Although beautiful, these aerial displays are costly in terms of fat stores and energy, so that harassment by people and predators can reduce the survival of these birds on their long migration south. Visitors to the area are best served by making use of the excellent interpretive centre at Johnson’s Mills.
During the balance of the time, they are out feeding on the mud flats on a tiny mud shrimp known as Corophium volutator. The Upper Bay of Fundy sites such as Johnson’s Mills are the only places in North America where this tiny amphipod crustacean the size of a grain of rice occurs in such incredible, critical densities, in some cases reaching 60 000 individuals per square meter. This incredibly rich, easily accessible food source enables the sandpipers to literally double their body weight in just a couple of weeks. This is crucial to the next leg of their journey, for when they depart the region after fattening up, they will be flying non-stop some 4 300 km over the ocean, all the way to northern South America, in a two to three day journey!
Links: Nature Conservancy of Canada; Awesome group shot of sandpipers from Birding NB
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There are over 50 Amazing Places in the Fundy Biosphere Region.
