Urban Birds of Vancouver

Literature Review

Birds are important aspects in cities as they are an indicator of healthy ecosystems – a link between people and local biodiversity. ^[1] Urban ecology is defined as ecological research conducted in an urban area, and “aims to describe and explain the processes determining the abundance and distribution of organisms as well as their interactions with one another and their environment "^[2]

Urbanization has cause declines in bird populations where cities only retain between 8-20% of their native bird species. According to The State of Canada’s Birds, habitat loss due to human settlement, industry, and forestry has caused the largest percentage of decline in characteristic bird species in the Pacific Coast. Research has found that total bird density is actually higher in urban areas than rural areas, however, species richness is higher in rural areas. This is due to introduced species in urban environments. Cities located near riparian systems often support more species of birds than other cities due to breeding areas within these systems. Fragmented habitats found in large parks and reserves provide some of the ecosystems required to support native birds. Urbanization adjacent to these fragments results in communities that can be dominated by superabundant flocks of invasive species. In studies on urban birds, researchers have found that the size of patch of native habitat and degree of isolation from other continuous areas of habitat affects species the most. Vancouver, English Bay, False Creek, and Burrard Inlet have been designated as Import Bird Areas by Bird Life International.

Conservation and restoration of vegetation within urban areas could support larger numbers of native birds and provide areas for other species to thrive as well. To support conservation and restoration, further citywide surveys around effects on avian diversity need to be conducted. Bird dispersal and settlement patterns may help to explain the geography of bird communities. This could benefit land-use planners to further understand how urban development affects birds in parks and reserves, residential areas, and within whole ecosystems. Vancouver is starting to take steps towards incorporating its knowledge of bird species into designs for urban development through the Vancouver Bird Strategy.

Research and Observations

Methods

My objective of this study was to understand the differences between the species that lived in different areas of the urban gradient, from suburban, urban encroachment, and urban. I collected data on species presence, total number of bird species detected, and the relative abundance of individual bird species.

I collected data in three areas around Vancouver - UBC, Kitsilano, and Downtown. UBC campus is located on the western peninsula of Vancouver and is surrounded by a forested park, Pacific Spirit Park. Downtown Vancouver is mainly commercial area with a large park in the North-West, Stanley Park. Kitsilano is a neighbourhood in Vancouver located along West 4th Ave and West Broadway, between Granville Island, Point Grey, and the south shore of English Bay.

Map of the study areas

Mean daily temperature during the study period ranged between 8 and 5 degrees Celsius. Each data collection occurred on a cloudy and mild day from 3:00 to 4:00 pm. I sat and watched one area, vision of 180 degrees, for one hour each. Each location was collected at once.

I used the guides created by the City of Vancouver to help identify the species I found at each location.

Findings

A total of 11 different species were found throughout the research with 7 common species, and 4 species only spotted once. 5 species were seen at UBC. 6 species were seen in Kitsilano. And, 4 species were seen Downtown. Species found most are Crows which were found through all three areas. European Starlings and Seagulls were found in two out of the three areas.

The total number of birds, or bird density, was 12 birds at UBC, 10 birds in Kitsilano, and 65 birds Downtown. Thus, I found total bird density to be higher in urban areas than suburban areas, however, species richness is higher in suburban areas.

Below, is a table of the species and abundance found in each location.

Findings Species and Number of Abundance

UBC	Kitsilano	Downtown
Seagull (5)	Bushtit (2)	Seagull (23)
American Robin (3)	Brown Creeper (2)	Pigeon (38)
Chestnut-backed Chickadee (1)	Pine Siskin (3)	Cooper's Hawk (1)
Crow (2)	Crow (1)	Crow (3)
European Starling (1)	European Starling (1)
	Hummingbird (1)

Connections to Lecture Material

Habitat Suitability

Habitat suitability is limited by abiotic and biotic features. Abiotic features can be defined as climate and nonliving environment. Some birds are able to tolerate a broad range of abiotic features while more sensitive species cannot. Constraints like climate, topography, elevation, and soil type affect where birds are able to live. The abiotic features of the environment change drastically in an urban setting which affects which species tolerate different areas. The lack of natural features causes many birds to not be suited to live in cities or even suburbs.

Biotic features include interactions with other species such as herbivores, predators, competitors, and species that rely on one another. In an urban environment, the species that has the most affect on bird species are humans. Biotic interactions between birds and humans vary depending on how close in proximity they interact and in urban areas the proximity would be the closest. Birds interpret humans as threats, like a predator, and respond with avoidance measures such as flying or dispersing to less densely populated areas.

Abiotic and biotic features act together to determine distribution and abundance. By the data collected, it appears that Seagulls and Pigeons are the most adapted to live within the abiotic and biotic features of an urban environment. Crows appear to be well adapted for each of the three environments' abiotic and biotic features.

Community Structure

Communities may be defined by the physical characteristics of its environment. A biologically defined community uses the presence and importance of abundant species as the basis of community delineation. Communities can be characterized by complex networks of direct and indirect interactions that vary in strength and direction. Urban birds could be characterized as completely different communities from birds of the same species that live in urban adjacent and suburban areas, even though they are connected in many ways.

Species diversity combines the number of species and the abundances compared with those of the other species within the community. Species richness is all the species in the community. Species evenness is the abundance of each species relative to those of the other species within the community. The presence of abundant species that create these community structures varies incredibly depending on the urban infrastructure and availability of parks and reserves. Diversity, richness, and evenness can still be increased in urban, urban adjacent, and suburban areas through proper urban planning.

Island Biogeography

Island biogeography theory, which examines the effects of island isolation and size in relation to species richness, immigration, and extinction rates, and has been applied to habitat patch dynamics in fragmented urban areas. Poor dispersal abilities of native bird species apparently prevented them from migrating even short distances (<100 meters) through developed areas. Dispersal affects population density by increasing densities where organisms move and decreasing populations left behind. Density affects dispersal when animals move in response to crowding. Dispersion depends on the location of resources, competition, dispersal, and behavioral interactions. Spatial arrangements generally match spacial arrangement of conditions of growth (temp, soil, light). Biogeography is the variation in species composition and diversity among geographic locations. The area we use to define species diversity measurements can be critical to our interpretation of the processes controlling biogeographic patterns. Island size controls extinction rates through increased competition and predation. Distance controls immigration rates. Regional differences in species diversity are influenced by area and distance, which determine the balance between immigration and extinction rates.