Transcript Welcome to our Workshop! Cities as Habitats for Birds October 12

Urban Ecology:
A Primer on Urban Birds
Summer Institute 2009
The red tailed hawk, Pale Male,
perches above his territory amidst
the din of New York City.
Birds are useful indicators of ecological
conditions; long-term bird surveys can
provide a window into the ecosystem
health of the city, while teaching students
important concepts in urban ecology.
In 2003, a student on an Audubon field trip to
Mount Auburn Cemetery photographed this
young male red-tailed hawk perched on a
headstone with a baby turtle clamped in its bill.
Ecology of Urban Birds
Urban avifauna are noted for
adaptability with respect to
foraging behavior, territory size
and social structure
Clockwise from upper left:
House sparrow (Passer domesticus)
- actually not a true sparrow, part of
the Old World guild of weaver
finches (introduced in 1851 - now
150,000,000); European starling
(Sturnus vulgaris) was introduced in
1890 (now 200,000,000); Brown
headed cowbird (Molothrus ater) is
our only common nest parasite originally tied to bison populations;
Common grackle (Quiscalus
quiscula) is the common bird of park
lawns; American crows (Corvus
brachyrhyncos) are very adaptable
to cities but may soon be wiped out
by West Nile Virus,
Peregrine Falcons An Urban Success Story!
Placed on the Endangered
Species list nearly thirty years ago,
the peregrine falcon has made an
incredible recovery from the point of
near extinction. Impacted by DDT it
was extirpated from the eastern
United States and nearly wiped out
nationwide.
Historically, approximately
4000 nesting pairs represented a
stable population prior to DDT. That
number fell to 275 nesting pairs in
1975. Strict controls on the use of
DDT, plus a dedicated reintroduction
effort has brought the population
back to nearly 4000 nesting pairs many in urban areas such as Boston
and New York.
Peregrine falcons (top), and other members
of the Falconidae, such as kestrels and
merlins are the acrobatic predators of the
urban skyline. Peregrines are capable of
level flight that exceeds 50mph and can dive
(stoop) at 200mph in pursuit of avian prey.
Their ecological niche as cliff dwellers - and
taste for pigeons and house sparrows - make
them urban neighbors.
Introduced avian species
can expand their range
dramatically over short
periods of time. Starlings
were introduced into New
York City in 1890 - they
are now now nearly
cosmopolitan. Mynas,
although similar have not
expanded their range.
Left: Common mynas (Acridotheres tristis) are also
introduced urban Icterids (family that includes
starlings) - but have a much more confined range in
North America.
Analysis of trends suggest that most successful urban birds are
likely to have been pre-adapted to mixed environments.
Top: Data for 45 common
species of birds found in urban
habitats reveal that most are
naturally found in wooded or
mixed habitats - grassland
specialists are rare.
Bottom: National trends show
both increases and decreases in
urban bird populations on a
species-specific basis.
Bottom line… there are great
opportunities for student science
research and with meaningful
contributions to conservation!
Right: Island biogeography
provides an intriguing
theoretical way to investigate
urban bird communities. Data
from cities all over Europe
suggest that urban habitats
really are like islands.
Bottom: Even urban parks can
become saturated with avian
territories - forcing residents
out onto the street!
from: Esteban & Jukka (2001), Biodiversity &
Conservation 10:2023-2043.
Bird species richness in Madrid is negatively associated with
the amount of paved ground within the park boundaries
Biodiversity declines
as fraction of
pavement increases
Typically, parks are designed with either an impervious landscape design - or
with a “naturalistic” landscape relief. The latter design enhances avian
biodiversity by allowing for a more heterogeneous environment.
Data from long-term Christmas counts suggest that crows
successfully exploit urban habitats and thrive in cities
Christmas Counts
provide a reliable window
into the population trends
of urban bird populations.
In Seattle, the crow
population has grown in
response to increased
human domination of the
landscape.
Data from
Massachusetts indicate that
urbanized habitat support
larger social groups*
*from: Auger, Auger & Strauss (1990),
Wilson Bulletin 102(4):615-622.
A crow family group. American Crows form cohesive social
groups of related family members that help the adult breeding pair
raise young. In urban territories, ecological niches are saturated and
reproductive success is often gained indirectly via inclusive fitness
The way a crow
Shook down on me
The dust of snow
From a hemlock tree
Has given my heart
A change of mood
And saved some part
Of a day I had rued
Robert Frost - Dust of Snow
Crows appear to be the victims of the disease - not the critical
hosts. In order to be good hosts, they need to maintain viremia for
at least 20-100 days, so that they could pass on the virus to others.
Ovenbirds limited by habitat fragmentation
Researchers in Canada observed lower rates of
pairing between male and female birds in
altered habitats.
Contiguous forest:
Agricultural lands:
96%
86%
Data from Missouri found
road effects on pairing:
>300 meters from road:
<300 meters from road:
76%
22%
Bayne & Hobson (2001), Auk 118(2):380-388.
Van Horn, et al. (1995), Auk:759-768.
Waterbirds can serve
as bioindicators of
changes in trophic
dynamics…
Great-crested grebe (P. cristatus)
Black-necked grebe (P. nigricollis)
Changes in great-crested & black-necked grebes wintering in grebes in
Mar Menor Lagoon (Spain) as it relates to nitrogen flow within the lagoon
from: Viaroli, et al (2005) Hydrobiologia, 550:221-235.
Researchers in Phoenix investigated bird
biodiversity in neighborhoods and parks and measured the wealth of diversity and
the human wealth of the neighborhoods
Paige Warren and her research colleagues
looked at the urban mosaic in a new
way… shifting from traditional urban-torural gradients, to the city as a patchwork
of neighborhoods - each with different
economic conditions.
From: Kinzig, et al. (2005), The
effects of human socioeconomic
status and cultural characteristics
on urban patterns of diversity,
Ecology and Society 10(1):On-line
.
Research in urban neighborhoods in Phoenix suggest that bird
diversity and human wealth are positively correlated
Similar to data from plant communities,
wealthier neighborhoods had more
species of birds. Some species such as
the cactus wren (left) and hooded oriole
(right) were only found in wealthy
neighborhoods.
Warren and her colleagues believe that human influence
occurs at two scales: bottom-up and top-down
Conceptual framework for enhancing avian biodiversity in our cities
Cape May
warbler - one
of our “rare”
neotropical
migrants.
Lyme Disease System
• Introduction to ecology
• Agent: bacterium (Borrelia
bergdorferi)
• Vector: deer tick (Ixodes scapularis)
• Hosts: white footed mouse
(Peromyscus leucopus) and whitetailed deer (Odocoileus virginianus)
• Incidental hosts: birds, voles, red
foxes, coyotes, humans
Left: Sedated red fox being fitted with a radio-telemetry collar.
Middle (2): Spirochete bacteria responsible for causing Lyme Disease. Upper
right: Adult, nymphal and larval stages of the deer tick
Lower right: Common yellowthroat found to be a competent host in Ontario
West Nile Virus Disease System
• Agent: Virus (Flavivirus)
• Vector: Mosquitoes (Culex spp.), found
in 43 species
• Hosts: wild birds, possibly ducks and
pigeons critical to maintaining life cycle
• Incidental hosts: mammals, bats, frogs
(Rana ridibunda), possibly horses
Culex sp female, laying eggs
Great tits (Parus major) use a variety of acoustic
signals - some are to establish boundaries.
This European songbird
lives in variable social
groups. Part of the year,
the adult males establish
territories and sing
elaborate courtship calls in
order to attract female
mates.
Bird biodiversity is
generally lower in urban
areas due to habitat
fragmentation - and quite
possibly anthropogenic noise!
Slabbekoorn, H., and M. Peet. 2003.
Birds sing at a higher pitch in urban
noise. Nature 424(July 17):267.
http://acp.eugraph.com/news/news03/slabb.html
The data the team have
analyzed come from recordings
of 32 males in various parts of
Leiden. The researchers also
took a series of recordings and
background-sound
measurements in each location
before, during, and after rush
hour.
The average minimum
frequency of the males' songs,
ranging from 2.82 to 3.77
kilohertz, was lower in quieter
neighborhoods than in noisier
ones. Urban noise, mostly from
engines in cars, trucks, boats,
and modern conveniences such
as leaf blowers, encroached on
birds' lower frequencies in the
loud neighborhoods.
Bioacoustics of Chickadee (Poecile
atricapillus) song contests reveal
hierarchies between competing males
Daniel Mennill & colleagues, Auburn University
and Queens College in Kingston, Ontario
Subordinate males
alter the frequency
of their territorial
calls in response to
playback songs of
dominant males
from nearby
territories.
Subordinate males
sing at a higher
frequencies.
• Federally Endangered
Species
• migratory- breeds along
eastern seaboard and
Great Lakes
• monogamous, ground
nesting
• easily disturbed by
humans
• Utilizes beachfront
corridors for nesting
• Reproductive success
reduced by human
disturbance
• Vehicle disturbance
must be minimized
during the fledging
phase of the
reproductive cycle.
Piping Plover Shore Birds
Piping Plovers respond to management at
Sandy Neck: Increased reproductive fitness
Sandy Neck Beach
Reproductive Success of Plover pairs
(measured as fledglings/pair/year)
Study Area
Before Closure After Closure Analysis
(1982-1989)
(1990-1996)
Experimental .43
2.25 (n=107) p<.001 (Z=9.78)
(n=56)
Control
1.13
1.45
p=.18 (Z=0.94)
(n=33)
(n=31)