May 22, 2013
Mute Swans: Beautiful natives or troublesome exotics?
Written by Jack Sanders
Thursday, 15 April 2010 10:59
Anne Singer lives near Fox Hill Lake in Ridgefield. “Every spring since I moved here 10 years ago except one, a pair of Mute Swans has nested on the series of ponds in the nature conservancy next to my house,” Anne wrote recently. “One year, only one swan showed up. It seemed lonely, but in September, after several attempts, it finally paired up with one of the half-grown cygnets from the family on Fox Hill Lake.
Anne wondered about this attack and why there are so many fewer swans around our lakes these last few years. “Fox Hill Lake has not had any for several years now, and there are many fewer on Rainbow Lake than there used to be, usually only two pairs now.”
“And another puzzle — where do the swans from our lakes go during the winter when the lakes freeze over? Do they move down to the open water on the Sound? I used to live in Riverside, and we would see many swans in the Mianus River near the Sound during the winter.”
First, a little background. The Mute Swan is considered an alien species, imported to North America from Europe in the 1800s to decorate ponds in parks and on estates. It is a beautiful bird, but unfortunately, a rather aggressive one.
“Many conservationists consider the Mute Swan to be an ecologically damaging exotic species,” reports the Connecticut Department of Environmental Protection. “Mute Swans’ territorial defense of an area may affect native breeding waterfowl populations. A recent study of interactions between Mute Swans and native waterfowl on freshwater ponds in southeastern Massachusetts concluded that the mere presence and antagonistic behaviors of swans caused native waterfowl to avoid nesting. Not only do the swans compete for nesting areas with other waterfowl, they graze heavily and uproot aquatic vegetation important as a food source for native waterfowl.”
Because various waterfowl species, especially ducks, are said to suffer because of the territorially aggressive Mute Swans, many wildlife officials recommend either hunting them or at least destroying their eggs.
This has prompted controversy. Patricia Feral, who heads Darien-based Friends of Animals, wrote in 2008, “Over the last three decades, Mute Swan numbers have remained stable at around 1,000, compared to tens of thousands of Canada Geese and ducks. And although swans have been known to enjoy underwater vegetation, to our knowledge they’ve never eliminated a plant species from an ecosystem. Vegetation is threatened mainly by commercial pollution — a human problem, like excess greenhouse gas emissions... A DEP waterfowl biologist told me while the agency couldn’t control pollution or global warming, it could control Mute Swans. Hardly a scientific justification for waging war on any species, let alone a group of a thousand birds.”
There’s a whole Web site, savethemuteswans.com, devoted to protecting the Mute Swans, going so far as to claim it is a native species around the world, like the Osprey.
Since these swans are very territorial, Anne may have witnessed the male of a mated pair chasing off an errant or challenging male. Or she could have seen a pair mating.
Year-to-year populations of a bird with such a limited total population are apt to vary for several reasons. Last year’s birds may have died over the winter. They may have found a new nesting lake, more to their liking. Food quantities or some other environmental change, unseen by us, may affect nesting site suitability.
While the population of swans at the Ridgefield Lakes may be down, there seems to be no shortage of them in the region. On Sunday we saw many on reservoirs in nearby Westchester and Putnam Counties.
As for Anne’s other question: Yes, for the winter, inland swans head down to the inlets of Long Island Sound where they can find unfrozen surfaces and plenty of underwater vegetation.
Coming up
Migration & Early Spring Migrants, workshop, Saturday, April 17, 9:30 to noon, $12 adults, kids free, Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x239, Greenwich.audubon.org
Birding By Ear, how and why birds vocalize, learn their sounds, Saturday, May 1, 9:30 to noon, $12/adult, Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x230, Greenwich.audubon.org
International Migratory Bird Day, Saturday, May 8, 6:30 to8: Early Morning Bird Walk; 8 to 9:30: Annual Birders Breakfast; 9:30 to 5: Raptor Science Conference “Monitoring and Managing Raptor Populations — Forging a Collaboration of Professional & Volunteer Conservationists,” Audubon Greenwich, 613 Riversville Road, RSVP 203-869-5272 x226, Greenwich.audubon.org
Spring migration bird walks, rain or shine, at 7 a.m., about 90 minutes, Wednesdays, April 21, 28, May 5, 12, 19, 26, at Fairchild Garden, meet in parking area on North Porchuck Road; Saturdays, April 3, 10, 17, 24, May 1, 15, 22, at Audubon Greenwich, meet in main parking area; Audubon Greenwich, 613 Riversville Road, 203- 869-5272 x230, Greenwich.audubon.org.
Saturday Morning Bird Walks with Luke Tiller; to register, sunrisebirding.com/walks.htm; 203-453-6724, This e-mail address is being protected from spambots. You need JavaScript enabled to view it
First Sundays, birding at Greenwich Point with Meredith Sampson of Wild Wings, and other guides, 203-637-9822.
Copyright 2010 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] yahoo.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877; or call 203-438-1183, extension BIRD (2473), and leave a message with your report, spelling your first and last names and telling us your town. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s Web site is www. sandersbooks. com.
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