Invasive Animals


The Winter Moth

The Northern Winter Moth (Operophtera fagata) has been epidemic on south Vancouver Island in Greater Victoria and at several locations north to Sidney.  It is a severe defoliator of broad-leaved plants, notably Garry oak, fruit trees and ornamental trees and shrubs.

The native Bruce spanworm (Operophtera bruceata), which is practically identical to the winter moth in appearance and habits, has been replaces in importance by the winter moth on south Vancouver Island.

Adult winter moths may be found from late October to the end of January.  Both sexes are drab-grey or grey-brown, without distinctive markings.

The females are flightless and crawl over the ground and climb up the tree trunks.  Eggs are laid singly or in small clusters under lichens or in crevices on any part of the tree.  They are pale green at first, gradually changing to bright orange, hatching from late March until about min-April.  The young larvae frequently drop from the twigs on silken threads and are borne a considerable distance on air currents.  Larvae commonly known as inch-worms or loopers feed on the swelling buds of host trees and on foliage, flowers and developing fruit until about the first week in June.

What you can do:

Trunk banding: Applications of “Tanglefoot” bands around tree trunks have been used for years to prevent the flightless females from climbing up to lay eggs.  This method is most affective against winter moths on isolated trees.

Sticky bands are useful mainly against the winter moth and Bruce spanworm. Apply the sticky material during mid to late October in a 10 to 15 cm (5 to 6 inch) band around the trunk.  The material can be painted on 25 to 30 cm wide (10 to 12 inch) plastic strips (6 mil thick) attached to the trees to avoid possible damage on smooth-barked trees.  Plug the bark crevices with caulking compound, fiberglass insulation or other suitable material to prevent moths from crawling under the bands.

Some monitoring of the bands is needed as they can become covered by debris or with large numbers of moths so that females may cross without being trapped.

Eastern Gray Squirrel

The eastern gray squirrel (Sciurus carolinensis) is a medium-sized squirrel with mainly gray upperparts and pale gray undersides.  It has a bushy, flattened tail and the backs of its ears are lighter coloured.  The commonly seen black squirrel is in reality the same species in its black form.

The eastern gray squirrel has actually two distinct forms: most adults are dusty gray overall, with pale underside and a silvery, flattened tail; occasionally a solid ebony black form of this squirrel is encountered.  In Canada, they gray form often has cinnamon highlights on the head, back and tail.  Some local populations, such as one in Calgary, are almost entirely black.

The original distribution of the gray squirrel ranged only over the eastern USA to just west of the Mississippi and north to Canada.  They are now present in Eastern USA, England, Ireland, Northern Italy, South Africa, and Western Canada. It is thought that they first appeared in the English countryside between 1876 and 1929 having been accidentally released from the London Zoo.  They gray squirrel squirrel quickly adapted to the native forests of the countryside in England, Ireland and Italy.  The gray squirrel is larger and more aggressive than its cousin, the Red, which is about half the size of the Grey at 250 to 400 grams.  Taking advantage of its size by foraging in the trees as well as on the ground, the gray squirrel out competes the smaller red, who stay in the trees to avoid predation. Grey squirrels are generalist feeders, while the Red Squirrel prefers conifer forests.

The mainstay of their diet is nuts and seeds, which they cache just under the surface of the soil.  Their caches of nuts are security for winter and stormy days; fresh corn crops, flowers, fruits, mushrooms, bird eggs, nestlings and frogs are all relished when they are available.

These squirrels live in trees year-round, either in cavities (often old woodpecker holes) or nests they build out of leaves.  These squirrels have been known to actually fight pileated woodpeckers for their homes – and win!  Nests are usually high up in tree crotches and can be hard to see in the summer, because they are made with green leaves and are hidden by foliage. They are easy to see in the winter, when the nest leaves have turned brown and tree leaves fall to the ground.

Eastern Gray Squirrels have two litters each year. The first is in the spring, the second in late summer. Two or three young are in each litter. The second litter spends the winter with their mother and they usually live to be about five years old.

The most important predators of Eastern Gray Squirrels are hawks, owls, Red Fox, Raccoons, and snakes.  (Info from Squirrels of the West by Tamara Hartson and the Hinterland Who’s Who website.

What you can do:

Removal of any diet source is a must: bird feeders are notorious for attracting squirrels but good squirrel proof models are available at wild bird stores.

Gutter guards and covering down spouts will reduce the amount of squirrels seeking nesting sites in your roof.  There are no poison baits on the market that squirrels will eat.  Live trapping squirrels is a recommended method of removal either done by a professional or do it yourself.