Tuesday, April 11, 2023

Urban Pigeons

Arguably the most successful of all urban-living animals, pigeons (Columba livia) have become synonymous with cities. In fact, most pigeons today live in cities rather than outside of them! Although they're often viewed as the quintessential example of a "bird brain", pigeons have shown remarkable intelligence in how they adapt to and interact with their urban environments and the people that inhabit them. For example, studies have found that pigeons are able to identify individual people based on their facial features, and will likely remember people who treat them well or poorly and change their behaviour towards them accordingly.

Identification

Pigeons are fairly conspicuous and well known animals, appearing in every continent of the world except for Antarctica. Interestingly though, they don't follow any hard-set rules on colouration, but rather exhibit a wide array of patterns and colours, as is shown in the image below.

Image by pigeontype

Typically, most pigeons occupy the central area of the picture and show a mainly gray or bluish color. Their feathers are also iridescent, meaning they reflect light in a way that makes them look colorful, like a rainbow. A notable feature of pigeons is their calls, which sound like soft coos. The species is very social and if you see one, you'll likely see many more.

Benefits

Pigeons, being highly successful in their ability to live in urban environments, play an important role in urban ecosystems. They are omnivorous, meaning they eat plants and animals, though they tend to prefer grains and seeds. At times, they will also eat insects and earthworms though. Because there can be so many pigeons in any one city, they can form the basis of an entire foodweb, and serve as prey for larger urban animals such as birds of prey, cats, foxes, and coyotes. So, with this in mind, the pigeon could be seen as one of the greatest contributors to promoting urban wildlife!

Pigeons also serve a role in recreation. Think about it, how many times have you seen movies, TV shows, or even just pictures of someone sitting at a bench and throwing out bread or seeds for pigeons to eat? They, like all urban wildlife, bring an element of nature to an otherwise human-centric world, and provide an escape back to nature for many people within cities.

Image by Dan Kitwood

Despite this, some cities have considered making it illegal to feed pigeons and imposing fines on anyone who does. Why would this be considered? Well...

Problems and Solutions

Pigeons have picked up the nickname of "winged rats", referring to the general distaste most people have acquired for them as well as the fact that they spread disease. They have been shown to carry Escherichia coli, more commonly known as E. coli, which is a harmful bacteria that can infect humans and has lead to many food recalls due to it contaminating our food items. Naturally, this can cause a concern for public health. To combat this, cities have moved to begin discouraging pigeons from roosting in them, or at least in areas with lots of people present. They accomplish this through a variety of means, most of which involve creating environments that are not favorable for pigeons, such as by blocking off entrances to areas pigeons like to roost in or even using bird spikes, which are rolls with spikes on them, on things like roofs and trees.

Image by Elyse Wanshel


Sources

Belguermi, A., Bovet, D., Pascal, A., Prévot-Julliard, A., Saint Jalme, M., Rat-Fischer, L., & Leboucher, G., 2011. Pigeons discriminate between human feeders. Animal Cognition, 14, 909-914.

Silva, V., Nicoli, J., Nascimento, T., & Diniz, C., 2009. Diarrheagenic Escherichia coli strains recovered from urban pigeons (Columba livia) in Brazil and their antimicrobial susceptibility patterns. Current Microbiology, 59, 302-308.

Shifting Opinions of Urban Wildlife in Europe

A new long-term study from the Uniwersytet Jagielloński in Poland seeks to understand how public opinion of wildlife in cities has changed over a decade. Researchers distributed surveys to residents of Krakow, Poland, in 2010 and 2020, to understand how a shifting modern environment is affecting both humans and animals alike.

As Europe undergoes changes to land use policy, more and more interactions between humans and wildlife are being reported. Natural habitat is shrinking due to urban development, which forces wildlife to move into cities and other urban areas. Responses to the 2020 questionnaire found an increase in sightings of animals such as hedgehogs, red foxes, roe deer, stone marten, wild boars, brown hares, red squirrels, and more.

Citizens tended to prefer certain species over others: species such as foxes, squirrels, and hares were generally more well-liked than species such as boars and rats. Ultimately, the attitude towards urban wildlife in Krakow remained positive, with many respondents citing exposure to wild animals in childhood as the driving factor of their perception of animals as adults.

Despite an increase in human-wildlife interactions, people still feel that cities are not an appropriate place for wildlife. The researchers felt that a citizen education initiative to increase the general public's knowledge of urban wildlife species would be beneficial for both human safety and wildlife conservation, and that awareness campaigns are needed to protect both sides.

Basak, S.M., Hossain, M.S., O'Mahony, D.T., Okarma, H., Widera, E., Wierzbowska, I.A. Public perceptions and attitudes toward urban wildlife encounters - A decade of change. Science of The Total Environment 834, 2022. doi:10.1016/j.scitotenv.2022.155603 https://www.sciencedirect.com/science/article/pii/S0048969722026997

Public Perceptions of Wildlife in Chicago

New research from the Lincoln Park Zoo in Chicago, IL, USA found that as a result of reduced human activity during the COVID-19 lockdowns, residents of Chicago were able to observe wildlife significantly more than before 2020. During a stay-at-home order, the Zoo distributed online questionnaires to understand what kinds of wildlife species were living in Chicago, and if the wildlife were occupying certain areas of the city over others. 

Urban wildlife was found to differ between certain parts of the city: in richer and greener neighbourhoods, residents were more likely to see an increase in wildlife presence, especially more preferable species like deer, rabbits, and birds. These experiences with nature may have helped people to cope with the stress of the pandemic, and support for animals in cities is strongly associated with sightings of these "preferable" species. Some pest animals, such as rats, had an increase in sightings after restaurant closures, as these animals were normally able to feed themselves from garbage and other food waste created by humans. Since everyone stayed at home, these animals were left with no choice but to venture into public parks and areas to look for food.

The first stay-at-home orders during 2020 resulted in a phenomenon known as the "Anthropause," in which reduced human activity caused an increase in urban wildlife sightings in major cities, as well as a change in animal behaviour. Studies show that positive experiences with wildlife can benefit physical health, mental health, and happiness; and that frequent wild animal sightings may promote greater interest in urban wildlife, ecosystems, and nature among the general public.

COVID-19 and the resulting lockdowns provided a unique opportunity for scientists to measure how a large-scale change in human activity, such as the anthropause, will affect human-wildlife relationships, and to increase support for wildlife. The researchers at the Lincoln Park Zoo found that people with kids were more likely to express support for wildlife, and that more frequent interactions with nature can positively influence public perception of wild animals.

Some examples of ways for residents in cities to connect with nature include public gardens, citizen science initiatives, and the creation of urban wildlife rehabilitation centres (UWRCs).

Public gardens. Gardens with a greater variety of native plants will attract many different types of birds and pollinator species such as bees and butterflies. Urban vegetation will also provide shelters and refuge for wild animals, and urban plants filter harmful gas like carbon dioxide. Trees in urban areas provide humans and animals alike with shade from hot temperatures and sunlight.

Citizen science initiatives. As a result of lockdowns and increased urban wildlife sightings, public perception of wildlife is shifting. Common news stories from 2020-2021 include domestic animal escapes, and the viral story of Shakira getting attacked by wild boars in Spain. In an increasingly online world, scientists and wildlife activists have taken to using websites like Twitter and Instagram to promote causes, such as #SaveLACougars and #relistwolves. However, the conservation of wild animals in urban spaces relies largely on help from the general public.

Urban wildlife rehabilitation centres (UWRCs). These facilities combine animal rescue and education. Some examples include Hope for Wildlife and WILDNorth in Canada. Often, animals are brought to UWRCs with illnesses and diseases, and receive treatment, promoting the conservation of these wild animals. Interestingly, UWRCs saw an increase in admissions during the stay-at-home orders, which they believe is due to increased time spent at home causing an increase in exposure to urban wildlife.

The aftermath of the COVID-19 pandemic continues to inform scientists about animal-human interactions in cities and may provide insight for a wildlife-friendly city of the future.


Coman, I.A., Cooper-Norris, C.E., Longing, S., Perry, G. It Is a Wild World in the City: Urban Wildlife Conservation and Communication in the Age of COVID-19. Diversity 2022, 14(7), 539. doi:10.3390/d14070539 https://www.mdpi.com/1424-2818/14/7/539

Murray, M.H., Byers, K.A., Buckley, J., Lehrer, E.W., Kay, C., Fidino, M., Magle, S.B., and German, D. Public perception of urban wildlife during a COVID-19 stay-at-home quarantine order in Chicago. Urban Ecosystems 26, 127-140. 2023. https://link.springer.com/article/10.1007/s11252-022-01284-x

Did the COVID-19 Lockdowns in Early 2020 Allow More Wildlife to Move Into Cities?

Have you ever wondered, "What would animals do if all the humans disappeared?"

Following the COVID-19 lockdowns in early 2020, many news stations reported sightings of wild animals in cities, with many people believing it was due to the lack of human presence. In HBO's new hit television series, The Last of Us, a scene in the final episode shows main characters Joel and Ellie feeding giraffes in a post-apocalyptic Salt Lake City, devoid of any humans. 

Historically, urban areas where many people live closely together were thought to be "biological deserts": places with low amounts of wild plants and animals and little habitat. The first wave of coronavirus allowed a unique opportunity for scientists to test how wildlife will adapt to a world without humans. A new study from Texas Tech University (TTU) aims to understand the indirect effects of COVID-19 and the lockdowns during early 2020 on urban wildlife. Let's break down the main goals of the study:

Importance of urban vegetation on biodiversity. By studying the types of trees, shrubs, and plants in our community, they can understand the layers of nature in an urban setting — the animals, the bugs, the water, the soil, and so much more.

Public perceptions of biodiversity. The general public's understanding of biodiversity will differ from a biologist's. Websites such as iNaturalist and Zooniverse include members of the public in scientific research and can help expand their knowledge of science.


Before we can understand the effects of COVID-19 lockdowns on urban wildlife, we need to look at the different kinds of wildlife in our communities before 2020. Insects provide valuable services to humans, such as pollination, pest control, decomposition, and as a source of food; with insects providing an economic value of USD $57 billion per year. Iconic species such as the monarch butterfly and honeybee are fantastic examples of bugs in our backyards, uniting humans and bugs in the common goal of protecting the environment through conservation.

Interestingly, cities are able to serve as refuges for some insects, as many species have small resource requirements. Programs such as "No-Mow Month," where residents are encouraged to not mow their lawns, help provide insects with habitat and food resources, which benefits the soil, gardens, parks, and biodiversity in their community.

Animals such as birds, fish, cats, rodents, dogs, squirrels, rabbits, and others are usually seen as troublesome due to their behaviour and larger size. These animals prefer sheltered habitats, and lots of vegetation, so they can hide from predators. A new type of gardening called "informed gardening" has been promoted online in recent years, encouraging homeowners to provide complex structures for wild animals, choosing plants carefully to be most nutritious for wildlife, and installing permanent water sources.

As more homes are built in cities, the different kinds of plants found in cities will decrease. Many of the plants in private yards and in public parks are mostly non-native plants, which are less beneficial to urban wildlife than native plants.

During the spring of 2020, humans were encouraged to isolate themselves to prevent the spread of coronavirus. This sudden change in human activity in major urban centres was dubbed the "anthropause," resulting in an increase in the quality of urban habitat. People spent less time in compacted urban areas and more time in green spaces, public parks, and nature. Wild animals began exploring empty urban places made quiet by the lack of human presence, as well as animals used to being fed by humans such as birds, cats, and squirrels. 

An increase in human presence in green spaces may have increased the number of sightings of animals in urban places that were previously going unnoticed. In Spain, a citizen science project measuring the activity of birds noticed that the behaviour and activity levels of birds remained constant during the first wave of lockdowns despite an increase in sightings and reports. Overall, reduced traffic worldwide also caused a decrease in vehicle-wildlife collisions. 

The study listed four factors that define the shelters and habitats used by urban wildlife:

Plant community composition. This factor looks at what kinds and types of plants grow in the community — how many trees, shrubs, flowers, gardens, and more.

Plant species richness. This factor looks at the number of different species of plants growing in an area.

Vertical and horizontal vegetation structure. This factor looks at the shape of plants growing — are more plants growing taller, or spreading out to cover the ground?

Plant community successional stage. The last factor looks at how old the plant is — are there mostly young plants and seedlings, or are many of the plants older and larger?


Despite the uncertainty worldwide, it was found that people felt happier when they had access to a public green space, a garden, or indoor plants. For those who live in a city, an urban green space may be the sole means of encountering plants and wild animals — with the COVID-19 lockdowns providing ample access for wildlife sightings. 


Coman, I.A., Cooper-Norris, C.E., Longing, S., Perry, G. It Is a Wild World in the City: Urban Wildlife Conservation and Communication in the Age of COVID-19. Diversity 2022, 14(7), 539. doi:10.3390/d14070539 https://www.mdpi.com/1424-2818/14/7/539

Wednesday, March 15, 2023

Urban Coyotes

Coyotes (Canis latrans) are, arguably, one of the most famous of urban animals in North America and, in particular, Alberta. These charismatic canines are close relatives of the wolf and domestic dog, all of which belong to the scientific genus Canis. Coyotes are not considered under any risk in terms of extinction threat, which means we do not see decreases in their population sizes, and they seem to adapt to the changing human-centric world far better than many other species do.

Identification

Coyotes have a variety of colors, but typically their coats are a mixture of mainly grey, light brown, and rusty red colors with some black and white. Coyotes look like they're about the same size as a medium-sized dog, but they weigh only about 13 kilograms (30 pounds) on average. The animals seem larger than they actually are because of their thick fur that allows them to survive cold winter temperatures. The small size of coyotes makes them fast animals; because they do not have to move large amounts of weight, they can move quickly at speeds of about 60 km/h.

History

Coyotes originated in the western areas of North America. However, over the past 200 years or so, they have spread to cover the entirety of the continent besides its northernmost regions. In the eastern areas of the continent, coyotes are larger than ones living in the west. This is likely due to crossbreeding with larger wolves. During the eastward spread, coyotes encountered human cities and, being adaptable animals, moved in to them to set up new habitats to live in.


Photo by Jim Cumming

Benefits

Coyotes are carnivorous animals and avid predators on small mammals like rodents. Because of this, they provide valuable pest control services. They’re also an animal that is unique to North America and have cultural significance to some Indigenous groups on the continent. The Blackfoot have stories of Napi (Old-Man) and Kipitaakkii (Old-Lady), both of whom are demigod figures that fill the role of creators of many animals, including humans. They are both well-intended tricksters and have strong connections with coyotes.

Coyotes also present interesting study areas for scientists. One study has found them interacting and cooperating with badgers to hunt ground squirrels. While coyotes are fast animals, they’re not good diggers. Badgers, on the other hand, have huge digging claws, but short legs and aren’t very fast. The two cooperate by having the badger dig up ground squirrel tunnels and, when the squirrel leaves, the coyote will chase it down and then share with the badger.


Photo by Charles G. Summers Jr.

Problems and Solutions

Being carnivores, coyotes can also attack pets. It is recommended that pet owners keep their pets inside their homes or supervise them while outside to ensure attacks do not happen.

Despite being a common sight in cities, coyotes do not like to interact with humans. If one is encountered, acting aggressively towards it by throwing rocks, making noise, and making yourself appear large can scare the coyote away. You also should not feed coyotes because this will cause them to overcome their innate fear of humans and could lead to further interactions and potentially attacks between coyotes and humans. Despite their presence in urban environments, it needs to be emphasized that coyotes are still wild animals and interaction should be avoided whenever possible.

Coyotes have been shown to carry a parasitic tapeworm known as Echinococcus multiocularis. Albertan coyotes in particular have high infection rates. This tapeworm poses a threat to humans, as it can parasitize them as well if they interact with an infected animal. Again, the best way to avoid infection is to avoid interaction with wildlife, and practice good hygiene by properly cleaning yourself after spending time outside.

Many attempts have been made to try and remove coyotes from cities. Despite successfully removing some, others just move in to take their place. As such, it seems that the species will become a permanent fixture within cities across the continent.


Photo by Jaymi Heimbuch

Sources

Hinton, J., Heppenheimer, E., West, K., Caudill, D., Karlin, M., Kilgo, J., Mayer, J., Miller, K., Walch, M., von Holdt, B., & Chamberlain, M., 2019. Geographic patterns in morphometric and genetic variation for coyote populations with emphasis on southeastern coyotes. Ecology and Evolution 9(6), 3389-3404.

Minta, S., Minta, K., & Lott, D., 1992. Hunting associations between badgers (Taxidea taxus) and coyotes (Canis latrans). Journal of Mammalogy, 73(4), 814-820.

https://www.alberta.ca/coyotes.aspx#:~:text=Coyotes%20in%20urban%20areas&text=Many%20urban%20areas%20in%20Alberta,coyotes%20and%20other%20wildlife%20species

https://www.edmonton.ca/residential_neighbourhoods/pets_wildlife/about-coyotes

http://www.native-languages.org/napi.htm

 

Frogs of Alberta

Northern leopard frog

The northern leopard frog (Rana pipiens) is a small-sized frog, averaging 5-8 cm. It is either green or brown in body colour with large, dark spots, giving the frog its name. Leopard frogs have raised ridges on the sides of their back, also called dorsolateral ridges, which are lightly coloured.
There are three populations in Alberta: the plains population, who live in southeastern Alberta, the boreal population, who live in the northeasternmost part of the province, and the Rocky Mountain population, who live west of the Rockies and are a part of British Columbian populations.
Historically, northern leopard frogs have been endangered in Canada. Over the last 20 years, the Albertan provincial government has taken measures to increase the population of northern leopard frogs, particularly in the Rocky Mountains. In 2022, the Wilder Institute/Calgary Zoo (WICZ) released 1,929 frogs into the wild to help boost their numbers.


Wood frog

The wood frog is known to scientists by the name Rana sylvatica, but may also be known by the name Lithobates sylvatica. In 2006, a researcher named Darrel R. Frost wrote an article called "The Amphibian Tree of Life" where he restructured the amphibian family tree, and changed the genus of the wood frog from Rana to Lithobates. Wood frogs have very prominent dorsolateral ridges that are lighter than the body colour, which can be red or brown. They also have a dark blotch on each side of the face, behind the eyes. The pattern on the body can be different from frog to frog. In Alberta, the wood frog can be found in every corner of the province, and is distributed in every province and territory of Canada.


Columbia spotted frog

Photo by United States Fish and Wildlife Service
The Columbia spotted frog (Rana luteiventris) has a brown body with lightly-coloured spots and dorsolateral ridges. They are found west of the Rocky Mountains of Alberta and in eastern British Columbia. Columbia spotted frogs enjoy a semi-aquatic lifestyle, meaning they can live on both land and in water, and will swim to the bottom of the nearest water body to hide when frightened. It is considered to be a true frog because it is a member of the family Ranidae.


Boreal chorus frog

Photo by J. N. Stuart
The boreal chorus frog (Pseudacris maculata) is a type of tree frog with a green or brown coloured body, and a dark stripe running along its side and passing through the eye. It is small, with the largest size for an adult being 4 cm. It is widespread in Canada, with its distribution including Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and the Northwest Territories; as well as extending into the United States. Boreal chorus frogs have a buccal sac on their chin, which they fill with air to make a call to other frogs in the area. The frogs can use their calls to announce their location to possible mates, or warn other frogs of predators in the area.


Canadian toad

The Canadian toad (Anaxyrus hemiophrys), unlike many of the frogs in Alberta, is brown or gray in colour, with black or red spots. It possesses a large bump on its head, called a "cranial crest," which sits just behind the eyes. On each hind foot, there is a claw which the Canadian toad uses to dig burrows. In Alberta, Canadian toads live mostly in the eastern region, extending into Saskatchewan and Manitoba. They will dig burrows below the frost line: a line which marks how deep the soil will freeze during the winter. Below the frost line, the soil will not freeze, and Canadian toads will hibernate until spring. They will also burrow into the soil to avoid the heat during the hottest months of summer.

Boreal or western toad

Photo by J. N. Stuart
This toad is known by two names: the boreal toad, and the western toad (Anaxyrus boreas). Its body is green or brown and covered in bumps, and it does not have any cranial crests on its head, unlike other toads in Alberta. The boreal toad possesses large parotid glands on the back of its cheeks, which create spit and special toxins called "bufotoxins."
In Alberta, boreal toads are found in the western central region, with the majority of its range in British Columbia and the western United States.

Great Plains toad

Photo by Drew R. Davis
The Great Plains toad (Anaxyrus cognatus) is green or brown in colour, with lighter-coloured skin on its belly. It is also covered in dark splotches, and has a cranial crest on the back of each eye, forming the shape of an L. Great Plains toads are found in southeastern Alberta, and southwestern Saskatchewan, with most of their distribution in the United States. They are nocturnal, which means they are most active at night and will spend their days burrowed underground, hiding from predators and the heat of the sun.


Plains spadefoot toad

The Plains spadefoot toad (Spea bombifrons) is not a member of Bufonidae, the family of true toads, unlike the other three toads found in Alberta. It has a brown or gray body covered in bumps, a large cranial crest between the eyes, and a vertical pupil. They also have a keratin-covered horned "spade" on each hind foot which it uses to dig burrows. In Alberta, the Plains spadefoot toad is found in the southern region of the province, and extends all the way across the United States, into Texas. Like the Great Plains toad, Plains spadefoot toads will burrow into the soil during the day to escape the heat, and burrow below the frost line in the winter to hibernate.


Frogs in an urban wildlife context

Alberta runs the Alberta Volunteer Amphibian Monitoring Program (AVAMP), which provides information about the frogs and salamanders that make Alberta home. Through AVAMP, Albertans can submit online their observations of amphibians in the wild. Observations aren't just seeing the animal, they also include hearing the noises that one makes, referred to as calls. They also provide tips for attracting amphibians to your yard.


Encouraging amphibians to move in

Frogs and salamanders prefer quiet, cool, and wet environments. A good first step is to pick a secluded area that is unlikely to be disturbed by pets or children. Allow any shrubs, greenery, or grass to overgrow and become "wild," the frogs and salamanders will hide in the leaf litter during the day and enjoy the moisture from the plants. Amphibians are semi-aquatic, so if there is a water feature or garden without fish, they will be very happy. 


Sources

Frost, R. Darrel et al. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History, 2006(297):1-291 (2006). https://doi.org/10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2
Image sources linked on image

Salamanders of Alberta


Tiger salamander

Photo by Drew R. Davis
Tiger salamanders (Ambystoma tigrinum) have broad and flat heads with small eyes. They have no single pattern, and can be green, brown, gray, orange, or yellow with lighter-coloured blotches. They are found in central and southern Alberta, and are nocturnal, which means they are most active at night. 


Long-toed salamander

Photo by Connor Long
Long-toed salamanders (Ambystoma maculatum) are an at-risk species in Alberta, which means their population is at risk of getting smaller. They are brown or green in colour, with a yellow stripe on their backs, and long toes on their hind feet. It is found west of the Rocky Mountains, and is nocturnal, like the tiger salamander. As a member of the family Ambystomatidae, it has costal grooves, which are ridges running top-to-bottom on the sides of its body.


Salamanders in an urban wildlife context

A CBC article from 2021 describes research undertaken by the Alberta Biodiversity Monitoring Institute (ABMI) to look for salamander populations in the Edmonton area. The technology, called Environmental DNA (eDNA), has been used in the monitoring of other animal populations, such as otters and minks. 


What is an axolotl, and are they present in Alberta?

An axolotl is a type of salamander that becomes sexually mature but retains features of baby salamanders, in a process called paedomorphism. As babies, salamanders live entirely in the water and have gills on the sides of their necks, which help them to breathe. Once the salamander is older, it undergoes metamorphosis, where the gills are absorbed and the salamander grows lungs. It then moves out of the water and onto land for the rest of its life. Baby salamanders also lack eyelids and tongues, and have flattened, tadpole-like tails.
These special salamanders are quite often the subject of viral online videos, but they are not restricted to only one species. Tiger salamanders in Alberta have been known to experience neoteny, which is a type of paedomorphism. Neotenic salamanders resemble baby salamanders but are full-grown adults. According to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), neotenic tiger salamanders have been found in Tyrrell Lake, Alberta.


Sources