While visiting my family up in Collingwood we decided to go check out Tiny Marsh.
We ended up hearing the Marsh Wren and seeing about 10 Black Terns. 250 different species of birds have been reported in the Wildlife Management Area.
Black Terns and Tiny Marsh
Unfortunately Black Terns are a provincially threatened species.
That is one reason why the Important Bird Area and the conservation plan at Tiny Marsh were put into place, as well as to protect its populations of resident and migratory birds. Birds here can be monitored, studied, and enjoyed by scientists and us.
A threshold of 50 pairs for significant colonies has been used in a Canadian regional study and records indicate hundreds of Back Terns breeding here. This makes the breeding population at Tiny Marsh nationally significant.
In August, when the babies are big enough to fly, the terns spend several weeks at feeding sites on bays and open water of the lower Great Lakes. From early to mid August you’ll be able to see significant numbers in the western basin of Lake Erie.
Then they migrate inland, either by themselves or in small groups, through the United States to marine habitat along the coasts of Central and South America. Here they lead a pelagic (spending a significant portion of their life on the open ocean) lifestyle while wintering.
Black Terns in Trouble
Since the 1930’s the number of Black Terns in Ontario has declined.
This species breeds in cattail and bulrush marshes with good stretches of open water. They live in small colonies and usually return to the colony in which they were born in order to breed. Because these wetlands are being drained for agriculture and urban and industrial development there aren’t as many locations now to feed and nest. Also the nest is virtually at the water’s surface, meaning that it may easily be destroyed by wind, wave action, or changing water levels (Ducks Unlimited Canada manages the water levels at Tiny Marsh ensuring that the Terns are not stressed during breeding season.) Usually only one chick is raised for each nest of two to three eggs.
Another possible factor, effecting everything in the natural world, is pesticides. Black terns have been observed foraging for insects behind ploughs and over grain fields on sprayed agricultural land. It has been suggested that reduced hatching success may be due to agricultural contaminants.
Part 2 on the Tiny Marsh Turtles is next.
Part 3 Mushrooms at Tiny Marsh