This population resurgence should be a cause for great rejoicing, since the expanding population of this obligate fish-eating bird, indicates an improvement in the health of the Great Lakes. Furthermore, Double-crested Cormorants eat "junk" fish, unattractive to commercial or sports fishers, and are especially important in consuming large quantities of invasive Round Gobies (Neogobius melanostomus) which are heavily implicated in the decline of native species.
Repeated analyses of the stomach contents of Double-crested Cormorants have revealed time and again that their take of "desirable" species is negligible, but hard science has failed to convince sceptics, or those with a preconceived dislike of the bird, and the clarion call of those wishing to control the population of this native species never abates.
The fact that they are colonial nesters leads to the death of trees in their colonies over time and this only serves to exacerbate the frenzy of people wishing to cull their numbers. The simple truth is that as the colony expands as part of a natural cycle, trees will be killed and the birds will move to another area, or adapt to ground nesting. What is left behind when the birds translocate is a great depth of guano, rich in nitrogen, which enhances the quality of the soil, and stimulates new growth of trees and the cycle will ultimately repeat itself, as it has done for millennia.
It is a disgrace that the management of Point Pelee National Park and Nature Conservancy Canada have lent their good name, and their financial and logistical support, to the destruction of thousands of birds from the colony on Middle Island in Lake Erie, using spurious, illogical reasoning to justify their inhumane and totally unwarranted slaughter.
The following video illustrates what is going on.
One can only hope that naturalists, birders and concerned citizens will withhold their support, both physical and financial from these two organizations.
I highly recommend The Double-crested Cormorant - Plight of a Feathered Pariah by Linda Wires, with superb illustrations by Barry Kent MacKay, as essential reading, to fully understand the long history of prejudice against this species.It is a damning indictment of humanity and our attitudes to wildlife.
As Keith Hobson, Environment Canada, has commented: The Double-crested Coromorant is extremely important, given the unprecedented nature of the history of the management of this species and its ramifications for the way we manage wildlife and respond to these apex predators we see as competitors. It is also a rare treatment that places human society as much under the magnifying glass as the bird itself.