UK Wildlife Blog

The race in the UK most closely resemble that of the Atlantic race B. c. candensis , which is native to Newfoundland, Baffin Island, and Eastern Quebec where it breeds and winters further south, from Nova Scotia to Florida. There is some evidence that a few of the smaller Todd’s Canada geese (B. c. interior) and a resemblance of some British Canada geese, to the largest form, the giant Canada goose has been noted (Hanson 1966). Some of the other, usually smaller, subspecies have been known to occur in the UK as wild migrants, often seen with flocks of white fronted and barnacle geese.
In the UK Canada geese are usually found in lakes with nearby grassland on which to graze but also occur on water bodies in moor land and on marshes. They feed on aquatic plants as well as grass and some other terrestrial plants.


They nest, sometimes in large colonies, from late March to May, in sheltered areas near water, often on islands. They lay a clutch of 5-6 eggs in a nest, which consists of a small depression in the ground lined with leaves and feathers. The female then incubates these for nearly a month before they hatch into downy yellow feathered goslings.


The adults and there young often group together and protect the young goslings from attack.



The first recorded occurrence of Canada geese in the UK is in 1665, which were those of Charles II’s collection, in St. James Park. Since this time and up until it was made illegal to do so (and perhaps after this too!) many Canada geese have escaped or been purposely released. The first recorded escaped Canada goose was one shot in Brentford, Middlesex on the Thames, in 1931. Since this time, these feral Canada geese have increased in range and numbers.
In there native North America, Canada geese perform a northward migration in order to moult, and this has been observed in some populations in the UK, although the distances travelled were not as great.

Adult Canada geese have few enemies and predators in the UK. The goslings are vulnerable to predators such as pike, mink, foxes and attack from territorial mute swans, but are often well protected by the adults. This, combined with the fact they are well suited to the climate and habitats in the UK, this has lead to the population growing to the large present day numbers. According to the RSPB website there are 82,550 breeding pairs in the UK. They have been known to cross breed with greylag geese and with European domesticated geese (there ancestors were greylag geese)


These large numbers have lead to problems. They have come into conflict with farmers and are regarded as agricultural pests due to their habit of grazing newly sprouted spring and winter wheat. They can also cause problems with native wildfowl. There territorial behaviour can disturbed and prevent other birds from nesting and their large size and tendency to nest in groups means only mute swans are not susceptible to their ‘bullying’ (in fact with mute swans the opposite tends to be the case!). They also take up valuable nesting sites and may attack the young and sometimes adults of other birds that come to close.
Methods of control of this non-native species have quite understandably been used to try and reduce, or at least stop an increase, in the number of Canada geese. Shooting is one method but the most humane effective method is properly timed egg pinning. This is where the eggs are pierced with a pin, which stops it developing. The adult will continue trying to incubate the eggs for a period of time, and if this pinning is timed properly, the adults won’t produce another clutch, the end result being no new young that year. Another method used between 1953 and 1957 was to catch the juveniles while they were flightless and move them to areas with no Canada geese, which lowered (or at least stopped an increase) in the population from where they were caught. But in doing this, other areas were colonised by the geese and these flourished and caused a three-fold increase in overall numbers between 1953 and 1969! Not exactly the best control method ever!
Canada geese are a good example of what happens when an alien species is introduced to and area outside its normal range, something we thankfully seem to be learning from. And I will be covering more of these ‘alien invaders’ in the coming months.

Also I've updated the Non-natives list here: Alien species



References

Hanson, H. C,, 1966, The giant Canada goose, Carbondale, Ill, Southern Illinois University Press

Lever, C., 1977, The Naturalized Animals of the British Isles, Hutchinson & Co.

RSPB, 2008, http://www.rspb.org.uk/




For more on the Non native fauna in the UK see here: Alien species