Urban Scavenger Hunt

The campus is a great place to observe and even study the activities of urban scavengers.  Whether it is the gulls, the raccoons, the tiny ants or even the more elusive Red Fox or Coyote, they

all make ample use of the campus environment. There are the scavengers that are active in the daytime such as the gulls, squirrels and the crows, and then there is another crew that takes over at night such as the raccoons, skunks, foxes, and coyotes.

Raccoons are omnivores and opportunistic eaters, which means they feed on whatever is most convenient. Their meals can include nuts, berries, fruits, acorns, grasshoppers, mice, fish, frogs, insects, small mammals, and ground-dwelling birds and their eggs. Raccoons are also adept scavengers. They rummage through garbage cans and compost piles and steal pet food that is left outside overnight. They climb bird feeders and dine on birdseed, as well. In urban environments their numbers are often double what they are in rural areas. The average urban raccoon population density is as much as 20 raccoons per square kilometre.

Wildlife biologists believe that raccoons have very sensitive nerves on the fingers of their front paws. They do in fact have thousands more nerve endings on their front paws than we do on our hands. When they are foraging for food in water, they are feeling around with their paws to gather sensory information.

Raccoons have enjoyed an “astonishing” surge in urban and suburban areas over the past 80 years, according to zoologist Sam Zeveloff. Because they’re so intelligent, they are developing skills that their rural counterparts do not have; they’re figuring out how to navigate human-made obstacles. They adapt to a vast range of sleeping spots, use their agile fingers to open garbage cans and enter garages and other buildings, and climb fire escapes.

Ring-billed Gull

Another urban scavenger is the Ring-billed Gull. Some people like to call them “rats with wings” but remarkably their populations were once in trouble. The gulls always nest in colonies and back in the 1800s when egg collecting was popular, along with the practice of adorning women’s hats with feathers, the gulls were vulnerable to being exploited and became vastly reduced in number. It wasn’t until the Canada-US Migratory Birds Treaty of 1916 that most birds received protection from egg collecting and the feather craze. Their numbers than stabilized around 1940 and then between 1960 and 1980, their numbers increased by 2000 percent!  In the Montreal region, over 75,000 pairs of Ring-billed gulls (Larus delawarensis) nest on islands located in the St. Lawrence River, on Rivière des Prairies and more recently on building roofs in industrial sectors. Researchers from UQAM and other Quebec universities have an ongoing research project to study the behavior of Ring-billed Gulls in urban and suburban areas within an integrated management framework. They collected and analyzed over 500 pellets from chicks on the Deslauriers island colony as well as stomach contents of 165 birds (adults, sub-adults and juveniles) collected in the colony, at landfills and in agricultural lands. Approximately 70% of items brought by adults to their juveniles were edible refuse (meat, bread, fries and potatoes), 9% annelids (earthworms), 8% insects and 7% vertebrates (small mammals).  They measured the calorimetric values of the different items and found that the diet obtained in landfills had the greatest energy content compared to agricultural lands.

Ants with Aphids

A very small urban scavenger are ants. Ants are the most abundant six-legged creatures on Earth, estimated to equal collectively the weight of all humanity, and make up 10% of the planet’s animal biomass. It is they who collect 90 percent of all insect corpses, and they also turn more soil than earthworms. The colonies of many different species are scattered throughout the campus and usually occupy just about every type of habitat. Many of them seem to “farm” aphids as if they were some sort of livestock because they tend to them, protecting them from predators, and then drink the sweet honeydew that they excrete.



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