American Coot visit Cobourg Harbour

Nature Notes for March 27, 2015

“There are some strange looking birds at Cobourg Harbour in amongst the Mallards. I know that this isn’t a very good picture, but you could help me identify them?” This paraphrases a request I received via the Willow Beach Field Naturalists web site last week. Fortunately, the identification was not difficult, even from a blurry photo.

They were American Coots. Coots are water birds, in the family that includes rails, moorhens and gallinules.

And they are strange looking. They are gray, about the size of a small duck, but with a small head and white chicken-like beak. The adults have a white “shield” on their forehead. Sometimes when they are on land, their oversized feet are visible. The feet seem several sizes too big for the size of the bird. Instead of webbed feet like ducks, coots’ toes are lobed. There is a fleshy projection along the side of each toe. This is an adaptation for walking on mud and floating marsh vegetation. These big toes are essentially snowshoes for mud.

 American Coot. Note the huge feet! 

photo © Rob Lonsberry Photography

In mild winters, a few have spent the winter in Cobourg Harbour. If the weather was really nasty for a few days, they took refuge in the storm drain that feeds into the yacht basin. They would probably have had a really difficult time this past winter and the ones being seen now are probably migrants.

Coots are quite eclectic in their choices of food, eating vegetation, some seeds, insects and aquatic invertebrates. The proportion of each in their diet depends on the season. American Coots are often, as at Cobourg, in amongst flocks of ducks. This is not just because they are waterbirds. They will frequently try to steal food that the ducks bring to the surface. Although coots can and do dive, the ducks can dive deeper than the coots and therefore have access to food that the coots can’t reach.

American Coots are uncommon and local breeders throughout Ontario’s marshes. In Northumberland, they have become quite rare breeding birds. A few may still breed in the Presqu’ile marshes, but even there they are hard to find in the summer. In Northumberland, American Coot is much more common as a migrant than as a breeder.

For nesting, coots need about a 50/50 mix of open water and emergent vegetation (i.e. cattails, bulrushes). They build floating nest platforms out of marsh plants that are anchored firmly to upright stems. They also build floating platforms for roosting and for the use of their chicks. The chicks are fed by their parents for several days, but they are able to swim and dive almost as soon as they hatch.

American Coots are quite sensitive to changes in water levels, so they may occupy a marsh one year only to abandon it if the water level goes up or down.

When they are present, they are often detected by their loud calls. Because these vocalizations are very similar to Common Gallinule, they can’t be identified to species by voice alone.

Although they migrate far enough south to have open water throughout the winter, they are not strong flyers. They have to run along the surface of the water, flapping furiously, for quite a distance before they become airborne.

Although coots are frequently seen as migrants among the flocks of migrating ducks, as soon as the ice clears from marshes, they will disperse to breeding areas. These areas may be as far away as the northern prairies.

Bald Eagles around Cobourg Harbour

Nature Notes for February 27, 2015

Where are the gulls? Usually when Cobourg Harbour is frozen, this is a favourite place for roosting gulls. This winter, there have been very few. It is not the cold that is making them scarce, but the presence of at least two Bald Eagles.

One adult and one juvenile Bald Eagle are being seen regularly around the harbour. Bald Eagles take four years to get their full white head and tail. They don’t breed until then. The dark body of these adults is actually a very dark brown. The juvenile was hatched last year. Its plumage is mostly brown with white blotches. Young Bald Eagles are frequently mistaken for Golden Eagles. (The latter occur in Northumberland County only in migration, and rarely in winter.)

Two Bald Eagles have been frequenting Cobourg Harbour.

photo © Rob Lonsberry Photography

In the late 1800s and early 1900s, there was, in some places a bounty on Bald Eagles. Fishermen on the west coast thought that the eagles were eating spawning salmon. They didn’t pay attention to the fact that the eagles were eating mostly dead and dying fish that had already spawned.

In that era, too, egg collecting was a common activity of those who studied birds. Fortunately for the birds, there is now recognition that this threatens the survival of some birds, particularly large birds such as eagles that reproduce slowly.

Despite these activities and despite often being shot, Bald Eagles were known to nest in several places in Prince Edward County and at Presqu’ile into the 1930s.

In the middle of the 20^th century, Bald Eagle populations were decimated by the use of pesticides, especially DDT. The buildup of chemicals prevented the birds from reproducing successfully. Since the 1970s, when DDT was banned in North America, Bald Eagle populations have slowly increased.

Eagles need a large undisturbed territory to nest successfully. Human infringement on their habitat has made some eagles abandon long held territories.

Bald Eagles have a very long life span. According to bird banding records, the oldest Bald Eagle reported was 31 years old. They usually only produce one or sometimes two young per year. They don’t breed until they are 5 years old. Since they reproduce slowly, only recently are populations showing an increase from the decline during the years of DDT use.

In the 20 years between the two Ontario Breeding Birdatlases, there was a marked increase in breeding Bald Eagles in southern Ontario. The field work for the second Atlas was done 10 years ago. Locally, the population seems to be on the increase.

Just last weekend, one observer saw 10 eagles on the ice on and near Presqu’ile Bay. The 2014 Port Hope-Cobourg Christmas Bird Count found a record high five Bald Eagles, most along the Lake Ontario shore. This count has recorded at least one Bald Eagle every year since 2007. The Presqu’ile-Brighton Christmas Bird Count has shown a similar increase, with a high count of 8 in 2013.

Rice Lake is also a good area to find Bald Eagles. There have been reports in recent years of them breeding on some of the islands in the lake and in the Trent River.

Although Bald Eagles remain a “Species of Concern” on the Ministry of Natural Resources Species at Risk list, Bald Eagles are one of the more successful conservation stories. Despite past human persecution, human intervention has now helped the species recovery.

The next time you see the gulls flush up in confusion at Cobourg Harbour, look up. You may very well be treated to the sight of a Bald Eagle.