Elegant and graceful, great blue herons are one of nature's most beautiful birds, and they are very visible along the shorelines of the Comox Valley and the Campbell River area.
The largest heron found in Canada, the great blue prefer shallow coastal waters, marshes, wet lands and river estuaries.
Local populations are year round residents, while others will migrate south to Mexico and northern South American countries.
Great blue herons are tall long-necked birds with a compact body, standing over a meter in height and weighing up to two and a half kilograms. Long fragile-looking legs stand on large splayed feet that are partially webbed, allowing them to wade in water or walk on shallow vegetation.
These herons have the ability to stretch out their necks or point their heads at different angles to blend in with their environment; when flying their necks double back to rest on their shoulders and their feet trail stretched out behind them.
Great blue herons have very distinct grey blue plumage in the adults with white breasts streaked with black. They also have white cheek pouches and pale grey necks.
During the breeding season the males grow long, impressive, slender, trailing black feathers on their necks, breasts, flanks, and backs.
Masters of camouflage and patience, these herons are stealthy hunters, standing motionless, moving only their eyes as they wait for their prey to swim by or they will silently stalk the unsuspecting food. Moving with great speed and agility the herons strike with their beaks to catch their prey — they do not impale their catch but use their beak like a pair of tweezers snatching the fish out of the water before tossing it up to be consumed head first to easily pass down the throat.
Although fish are one of the favourite food choices great blues will also dine on crustaceans, frogs, small rodents and other small aquatic creatures.
Great blue herons are very unique nesters, the most obvious choice for a nest would be in some kind of wetland similar to swans, but instead these lanky birds prefer to build their nests in the tree tops, forming a heronry, or rookery.
Usually solitary birds, the breeding season brings dozens of birds together with the males choosing the nest site, and both birds incubating the turquoise blue eggs.
Heron nests are very exposed and their successful breeding requires dedicated parents to guard the nest from predators, a task they share in order to deter attacks on the nest by ravens, crows and eagles.
Usually these birds will produce between seven and 11 eggs but the mortality rate is very high and often only one will hatch and survive the first year.
Baby herons are extremely comical with large beaks and a crown of fluffy down; many hatchlings will never make it to fledge from the nest as they are often pushed out of the nest by a sibling in the struggle to compete for food. Once they fall from the nest few will survive as the dense vegetation under the nest prevents the adults from being able to feed them on the ground.
Great blue herons are very difficult birds to rehabilitate as they are highly strung, easily spooked and secretive by nature; rehab housing has to provide a safe place for them to hide where they cannot see humans.
Do not try to attempt a rescue of an adult bird; they can be very aggressive, striking out with their beaks aiming for the predators' eyes.
M.A.R.S. initiated a great blue heron study made possible by funding from Shell Canada. We will be monitoring feeding areas and nest sites to find out more about their feeding and nesting habits.
Herons can be seen along the Comox Valley shorelines from Union Bay to the Oyster River, sometimes as a solitary fisherman while others as a larger group.
Some heronries are reused each year others abandoned, some like the Stanley Park colony seem to have adapted to urbanization along with the noise of traffic, sirens and general big city sounds.
Please try not to approach the herons, take photos from a safe distance and again, please do not let dogs chase the birds; these herons and their nests are protected and blue listed in B.C.
In the next few weeks we expect many wildlife species to be teaching their offspring the necessary life skills they need to survive, so please expect fawns and other mammals to be more visible use caution when driving.
If you find baby wildlife please call 1-800-304-9968 before intervening if a rescue seems needed please be aware of the exact location of the creature.
For general information call 250-337-2021 or visit our web site at www.wingtips.org.
Sandy Fairfield is the educational co-ordinator for the Mountainaire Avian Rescue Society (MARS). The MARS column appears every second Thursday.
No comments:
Post a Comment