This post was written by David Bree, Natural Heritage Education Leader at Presqu’ile Provincial Park.
While Presqu’ile is not the busiest park in Ontario, it can get pretty hectic at times during the summer. However, I’m pretty sure most people couldn’t guess where the busiest spot in the park is.
It’s not the line on Friday to register your campsite, nor the beach on a sunny Sunday in July. It’s not even the line for ice cream at the park store on a hot summer day.
It’s a place most campers never go…
Busy busy busy…
With quarreling neighbors and squawking youths, Gull Island is so crowded that you can’t leave your designated two-foot-square space without risking being yelled at and pecked at.
Well, of course! It is not a place for people, but rather a place for birds. Gull Island (along with neighboring High Bluff Island) is the site of the most diverse waterfowl colony in the Great Lakes, with seven species of colonial waterfowl taking up residence each spring.
A quarter of a million birds
During the breeding season with young in the nest, there may be a quarter of a million birds out there. While both Gull Island and High Bluff Island are crowded, Gull Island is easily the busiest.
Highly contested nesting space
Having no trees, all Gull birds nest on the ground, and nesting space is highly contested. It’s worth arriving early and reserving a spot.
Of the five species that nest on Gull Island, the eponymous gulls arrive first. Ring-billed gulls and herring gulls begin choosing sites in February and nesting begins a month later.
The double-crested cormorant arrives in early April and the Caspian tern shortly after. Common terns, by far the smallest birds, do not arrive until late April. By then it’s pretty full and these small, declining birds have a pretty hard time. So hard, in fact, that in some years before 2014 they failed to raise any offspring!
Saving the common tern
Nine years of research on the common tern conducted here by scientists at Penn State University have shown us how to help this species.
Common Terns perched on grid
As of 2014, one area of Gull Island has a raised rope grid that has open squares too small for other birds to pass through, but common terns can land. This gives them space to nest and protects the chicks from predators.
Running the gauntlet of angry bills
However, the other species are alone and manage to push and squirm their way to a nesting site to raise their young with varying degrees of individual success. All spring and summer, they must protect their space and nesting material from neighbors, and brave angry bills to bring food to their young.
And the noise!
Gull Island is easily heard from all parts of the park on calm days. Imagine what it’s like to be there!
What attracts birds to Gull Island?
Why do birds do this? Why put up with the hassle? Nesting in groups has its advantages. All those bills provide protection from predators. Hawks and owls usually do not manage to penetrate a colony.
Nesting on an island is also important, as it provides isolation from terrestrial predators such as foxes, raccoons, and coyotes. There aren’t many places like that and that’s why space on islands like Gull is so contested.
But Gull Island is not perfect
In reality, it is too close to the mainland and, in some years, a predator arrives there. Foxes and coyotes have caused major disturbances at times, with some predation and nest abandonment, but the density of birds on Gull Island can usually combat them.
The colonies on High Bluff Island have not been as strong in previous years, and one family of foxes caused the entire terrestrial cormorant colony to abandon High Bluff in 2013 and 2014. They went to Gull Island, of course, which made it even better! more populated!
These colonies, for all their bluster, are very sensitive to disturbance.
That is why these islands are prohibited for people from March 10 to September 10. But people can visit them the rest of the year and many people go to Gull Island.
A visit in September is an interesting and educational adventure.
It’s usually possible to just walk, if you don’t mind wading a bit. The water is rarely more than half a meter deep and it is not too difficult.
Most people go looking for migratory birds, but a visit to empty September bird colonies can give you an idea of what a waterfowl colony is really like. You can see the difference between cormorants that build raised nests with sticks and gulls that only use indentations in the gravel. You can also inspect the grill of the Common Tern.
On the darker side…
…it is also evident that many birds do not survive the summer. The stuffed corpses of young people and adults who lost the battle for life are scattered. Nature may seem cruel, but competition ensures that the strongest survive to continue the species.
And the competition doesn’t get much more intense than in our crowded, busy but crucially important waterfowl colony.
The colony can be inspected from a distance from Owen Point during the breeding season or…