The Common Cormorant, or Shag, Poses a Management Quagmire

As a little girl, one of my favorite books was a collection of nonsense poetry. I think it rubbed off on my own lyrical taste for funny rhymes. Any time my family went to the beach or lake and I spotted a cormorant, I’d recite this poem by Christopher Isherwood:

The common cormorant (or shag)
Lays eggs inside a paper bag,
The reason, you see no doubt,
Is to keep the lightning out.

But what these unobservant birds
Have never thought of, is that herds
Of wandering bears might come with buns
And steal the bags to hold the crumbs.


This strange behavior seemed perfectly reasonable to me, a budding human ecologist at the age of five. Now that I’m older and tend to question things I’ve read, I thought I’d better get it straight. The common cormorant, or shag, does not lay its eggs inside a paper bag; it sometimes chooses a cliff and uses sticks and grass, algae and feathers, often guano as a cement for the sturdy but messy nests. If trees are an option, the shag will build nests in them. From the 1894 article, “A Cormorant Rookery” by H.R. Taylor, “the great ungainly birds crane their necks this way and that, fearing to scramble away into flight lest their nests be robbed of their eggs or young. It would appear that the innate ugliness of the young cormorant would be sufficient guarantee against invasion, but to make their peculiar sort of defense more effective, I have seen Farallone cormorants, when I came quite near, go into contortions and disgorge the contents of their gullets. This cormorant seems to fear having its claim be jumped by another bird,” which is why it tends to build in inaccessible areas like the ledge under a crag.

In Rachel Carson’s lifetime, the pesticide DDT nearly wiped out the cormorant, or shag, but now the bird is thriving. It isn’t the most popular bird on the block. Bird-watchers will pull their binoculars away in search of a loon or an osprey—anything but a cormorant. The shag is a creepy snake-like black bird. I think there are numerous species of cormorants: these include the black cormorant (P. carbo), Brandt’s, Great, Olivaceous, Pelagic, Red-faced, the pied cormorant (P. varius), the white-breasted cormorant (P. fuscescens), the little pied cormorant (P. melanoleucos), the little black cormorant (P. ater) and the double-crested cormorant (Phalacrocorax auritus). The Double-crested Cormorant lives along inland waterways as well as in coastal areas. Eating a pound of fish (per bird) each day, a large group of cormorants can make quite an impact on a local fish population. They have nasty nest-building strategies and their sticky guano kills tree roots, trashing the vegetation and driving out other wildlife. There are groups that advocate for the killing of these unpopular birds and at least one group of anglers was arrested for killing hundreds of cormorants in Lake Ontario. The Cormorant Defenders International group wants to protect the shag. Currently there is an effort to control the cormorant population along the St. Lawrence River with a 13% decrease in nests success rate. For more on this story about the population control work, as covered by the Environment Report, visit: http://environmentreport.org/story.php?story_id=4626

For a March 2009 news release by FWS, Agencies Release Final Decision on Double-crested Cormorant Damage Management in Wisconsin, go to:http://www.fws.gov/midwest/News/release.cfm?rid=20

For USGS info on the Double-crested Cormorant, go to: http://www.mbr-pwrc.usgs.gov/Infocenter/i1200id.html

For Audubon info, go to: http://web1.audubon.org/waterbirds/species.php?speciesCode=doucor

For FWS Cormorant Management info, go to:http://www.fws.gov/midwest/MidwestBird/cormorants.htm

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s