Tuesday, February 16, 2016

Resident Geese

A group of resident Canada Geese sleeps along a trail. Note all the droppings in the background.

     Just about everyone is familiar with Canada Geese, emblematic symbol of migration in long V-shaped flocks. Indeed, the Algonquian-speaking native peoples of the East even had one of their 5 seasons named for the "co-honk" sound signaled by arriving geese. But these days, the Canada Geese we see are not normally the migratory creatures of the past. They are instead permanent residents of parks, golf courses, and lakes who's presence can cause many issues.

A resident goose sits on a paved path, unafraid of human presence. Note the droppings in front of it.

     While we have 7 (some argue up to 11) subspecies of Canada Geese with differing ranges and sizes, our resident geese are the largest. They are larger than the migratory Atlantic Canada Geese (Branta canadensis canadensis) that fly through here and overwinter along our coast. Originally called the Giant Canada Goose, Branta candensis maxima, it once was in trouble of extinction and had a limited range. That it now is so common and often reaches pest status makes for an interesting story.
     The now-resident Giant Canada Goose (Branta canadensis maxima) averages 13 pounds in weight and can reach 20 pounds. They can stand 45" tall, with the males (ganders) being larger than the females. They are the largest geese in the world. Giant Canada Geese are not thought to breed with other Canada Geese subspecies in the wild, though they will mingle together when feeding. Originally they ranged from Manitoba through Kentucky, but were considered extinct in the wild by the early 1900's. 
     Flocks however were being kept by some collectors and hunting groups. They were popular live decoys due to their larger size and thus visibility, being used to lure in wild flocks of other Canada Geese. Some were also released outside their natural range for hunting and decorative purposes. By 1935, the use of live bird decoys was outlawed and many hunters released their pets rather than destroy them. Some 21,000 were estimated to have been released, many adopted by local parks. 
     In the 1960's, a truly wild flock of Giant Canadas was discovered in Minnesota. A push for conservation and reintroduction of these geese reached nation-wide efforts and was extremely successful. Every park wanted to have some of these large birds and assist in their conservation. This, along with the protection of the released captive live decoys, made for the establishment of colonies throughout the USA. The Giant Canada Goose was not only saved, it expanded its range and reached huge populations.
     Migration in geese though is a learned behavior. Since generations of these geese had never migrated (despite their human assisted movement throughout the USA), they did not know how to do so. Some people may be familiar with the movie Fly Away Home and how geese were taught to migrate following an ultralight airplane. What some people do not know is that this is based on a true story, first with the experiments with local migration by Bill Lishman, and then based on experiments done by Dr. William Sladen at the Airlie Center in Warrenton, Virginia. The purpose was to see if Endangered Whooping Cranes could be taught to migrate, but first by using the more expendable geese. This was finally accomplished in 1993 with 18 geese that were taught to migrate 400 miles from Lishman's property in Ontario to Warrenton Virginia. 
     So our resident Giant Canada Geese have never learned to migrate and are with us all year round. This permanent residency and their growing numbers (estimated at 3-5 million these days) can lead to multiple issues. That these wild geese can live an average of 12 years old (though the oldest wild one was 30 years and the oldest domestic one 80) and can have 4-8 young yearly, means they can form very large flocks quickly. 

Goose goslings are cute.

     Though it is well known that they mate for life, this merely means that if the old mate dies, a new one is found until death does them part again. Both geese care for the young and are devoted parents who can act very aggressively in their defense. This can not only lead to complaints from people who get too close to the goslings, but means that these large birds are fairly successful at rearing their young. Many predators think twice before messing with an adult giant resident goose pair.

Resident goose droppings litter a boardwalk and the water underneath.

     Large numbers of geese lead to large numbers of droppings. A goose can poop every 20 minutes or so if it finds enough food. They are mostly herbivores, capable of grazing on grass and any other plants they find. They can defecate a pound of 3-inch long droppings a day. Multiply that by the number of geese, and you can see that "Lawn Carp" as they are sometimes referred to, can make quite a mess.

There are many reasons not to feed wildlife.

     This is why they are not welcome in many public areas, and why most places also ban feeding them. This attracts and accustoms them to those locations, while usually not being very healthy for the individual birds anyways. Goose dropping are not only a nuisance and unattractive, fouling lawns and swimming areas, but can also be unhealthy and affect water quality. 
     Because of their appetites and sedentary nature, they can have a very significant negative effect on the habitat as well. They not only compete with other waterfowl and wildlife for food, but also can destroy the habitat they all depend upon. Already in our region, areas that are replanted with SAV's (Submerged Aquatic Vegetation) often need to be fenced off to simply give the plants a chance to establish themselves. This imperils restoration and conservation efforts that affect all sorts of other wildlife and flora. A flock of geese can overgraze an area very quickly, and unlike their migratory kin, do so everyday so that the habitat can never recover. 

A resident Canada Goose grazes on the short grass it prefers.

     Large geese flocks can also have some tragic consequences in the wrong locations. Huge amounts of funds are spent yearly to prevent geese and other birds from being around airports. These still result in approximately 240 plane-bird collisions a year. Luckily, these are not often to the extent of US Airways Flight 1549 and the Miracle on the Hudson, but do cause concern.
     There are of course many methods attempted to prevent resident geese from causing these issues. Some tactics include pyrotechnics, hazing, chemical repellents, alteration of habitat (geese dislike long grass or brush where predators can sneak up on them), and even dogs trained to chase them. But in reality this just moves the problem to another area, and perhaps to places who cannot afford these tactics themselves. They do nothing to deal with the issue that these animals are overpopulated, will grow their numbers each year, and will continue to cause environmental and aesthetic harm. 
     So there are logically also attempts to control their numbers. These are sometimes complicated by the fact that Canada Geese are protected under the US Migratory Bird Treaty Act, despite not being migratory anymore. This means that depredation permits and/or other legal methods need to be obtained in order to control them. One of the methods that is sometimes approved are round-ups while the geese have young and are temporarily flightless. Often the meat is donated to the homeless and these can be very effective since the geese cannot fly away, but is often dealt with misinformed public outcry and poor portrayals by the media. While this may make people feel good about their actions towards the geese, they do not alter the damage these geese cause and ignore the plight of the habitat and those other animals/plants that are then critically affected.
     Another way to control the increase in resident goose numbers involves addling the eggs. This means using some method such as shaking the eggs or coating them in oil so that they can no longer hatch. If the eggs are simply removed, altered visibly, or destroyed, the parents will simply re-nest. Addling tricks the parents into wasting their time incubating dead eggs until it is too late for them to nest again. This is very effective in keeping numbers from growing, though it does nothing to quickly lower any overpopulated numbers that may already exist in these long-lived birds. 
     Another method that is used is extended hunting seasons and liberal game bag limits. By timing the season both before the migratory geese start migrating and reach our region, or starting them after they've left (in areas where migratory geese do not overwinter), their numbers can be harvested. While this can be effective, hunting of course is not always possible in all locations and so would not work in all locations. 

Resident geese are quite comfortable living side by side with people.

     Canada Geese are very adaptable waterfowl and have learned to benefit from close association with man. These giants may not have learned to migrate, but have learned to live along side people and survive in even very urban environments. In numbers that the habitat can support and that do not damage the habitat, these birds are to be admired for their ability to survive. But people need to understand the effects these huge birds can have day after day in the same locations and that they need to be managed for the health of the habitat and all its occupants, whether animal, plant and/or human. 
A gaggle of Canada Geese.
     More on resident Canada Geese in this short video from the Capital Naturalist YouTube Channel:

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