Wednesday, March 23, 2011


TRCA (Toronto Region Conservation Authority) are reviewing their management strategy for Mute Swans and Canada Geese.  While many Sam Smith park visitors enjoy seeing the swan families at Sam Smith, that does come at some cost to native species like Red-Necked Grebes who are also trying to breed in the park.  Read the letter below that was sent to Friends of Sam Smith Park by TRCA when more information was requested.  TRCA will have swan and goose info at the Sam Smith Bird Festival on May 28th and have lots of information available as well as staff to answer questions.

Currently TRCA manages Mute Swans and Canada Geese on waterfront sites (including Sam Smith) and select inland sites.  For Mute Swans management entails egg oiling, and for Canada Geese management entails egg oiling and a round up of moulting geese at a couple of locations.  We are updating the strategy to ensure that we are approaching the issue using the best science, monitoring and management tools available.  Mute Swans are managed because they are a non-native, invasive bird that have significant impact on native flora and fauna.  Specifically, Mute Swans are very territorial and will defend their territory against almost all intruders thereby excluding (and sometimes directly harming) many wildlife species from coastal marsh habitats at critical breeding times.  Mute Swans are also voracious eaters, consuming about 3.8kg of wetland vegetation a day.  This can seriously affect native wetland vegetation communities, wetland restoration efforts, and the availability of food to other species, especially waterfowl.

Based on the 2008 CWS mid-summer inventory (monitoring sites are grouped by general location) there were 98 adults in the Toronto Islands alone and an additional 463 adults between east of the Island to Oshawa Second Marsh and west of the Islands to Burlington.  Inland sites are not surveyed, so the numbers are an underestimate.  This same area in 2002 had a total of 240 adults, so the population trend is steadily increasing.  CWS staff note that the trend would have a much sharper incline if there were no control efforts underway.  The next survey will occur this year.  The Toronto population also fluctuates seasonally.  There were hundreds of Mute Swans across the waterfront in winter 2008-09.  While this doesn't impact nesting birds, it does impact wetland vegetation as they continue to forage in the winter and may reduce the availability of food and habitat to native species.

The only control method that TRCA uses for Mute Swans is egg oiling.  While this does not address all the effects they have on marshes, it will ultimately slow the population growth and reduce their impact on our native flora and fauna.  Oiling procedures following the US Humane Society protocol where eggs are immersed in water and only oiled if they are less than 10 days old (eggs older than this float, so it is easy to determine their age).  The management strategy is a region-wide plan that involves the collaboration and cooperation of multiple agencies and municipalities.  Public education is a major component of the strategy. 


mister anchovy said...

Very interesting post. When we see and enjoy the swans in the area, it isn't immediately obvious that the swans can have an adverse affect on other parts of the ecosystem.

Unknown said...

I think the dogs running free that no one wants to deal with that harass all the wildlife-especially where the grebes are nesting-along with chasing after the young minks are more of an issue.
Leave the swans alone if the dog problem will not be addressed.I never saw the swans bother the grebes-but I did see dogs.And the dogs don't read the signs saying keep out.

Anonymous said...

it does impact wetland vegetation as they continue to forage in the winter and may reduce the availability of food and habitat to native species. native wetland plants