A land manager's guide to conserving habitat for forest birds in ...

Researcher removing bird
from net — photo: Scott Gillingwater
How do we measure bird population trends?
The North American Breeding Bird Survey (BBS) was created in 1996 as a large-scale avian
monitoring program to track the status and trends of North American bird populations. Managed
as a cooperative effort between the United States Geological Survey’s Patuxent Wildlife Research
Center and Canadian Wildlife Service’s National Wildlife Research Centre, the BBS is an
important tool for identifying bird conservation priorities. Following a rigorous protocol, BBS data
are collected annually by thousands of volunteers skilled in bird identification. Audio and visual
point counts are used to survey breeding bird composition at randomly established roadside
routes throughout Canada and the United States. Once analyzed, the data provides an index of
bird abundance that can be used to determine population trends of more than 400 bird species.
Migration monitoring stations are also used to track the number of birds migrating along
migration flyways each year. Special nets catch birds and allow them to be tagged and counted
by species, age, and sex. Some stations have been running since the 1960s, monitoring migrating
birds in both the spring and fall. The numbers passing through and information on those banded
and released at these stations can be used to track year-to-year changes.
Other programs are run at a mix of scales to track populations (www.mnr.gov.on.ca/
stdprodconsume/groups/lr/@mnr/@lueps/documents/document/mnr_e001791.pdf). One of
these includes the Forest Bird Monitoring Program (FBMP) which began in Ontario in 1987 to
provide information on population trends and habitat associations of birds that breed in the
forest interior. Sites consist of three to five stations in woodlands where volunteers who are skilled
at identifying birds by sight and sound, perform 10 minute surveys, called point counts, twice
between late May and early July.
The National Audubon Society’s Christmas Bird Count (CBC) represents the longest running
wildlife census used to assess the health of bird populations and help guide conservation action.
2009 marked the 109 th year citizen scientists annually braved snow, wind, or rain, to take part in
the count. Over 2000 localities across Canada, United States, Latin America, and the Caribbean
conduct CBCs; 70 are located in Ontario. These observations have combined into a huge
database that reflects the distribution and numbers of winter birds over time. The principal
objective is to cover a 24 kilometre (km) diameter circle as completely as possible, tallying all the
birds encountered, on a single day during a two and a half week period around Christmas. These
data are then compiled and submitted to the Audubon Society and Bird Studies Canada.
The Ontario Birds at Risk (OBAR) program was launched in 1994 to work towards the
protection and recovery of vulnerable, threatened, endangered and other bird species at risk in
Ontario. OBAR is designed to monitor the status of these species and their habitats, and to
provide the necessary data to develop management plans for their protection. OBAR is a joint
undertaking of Bird Studies Canada and the Ontario Nature, in cooperation with the Canadian
Wildlife Service, the Natural Heritage Information Centre, the Ontario Field Ornithologists, the
Ontario Ministry of Natural Resources, and the Royal Ontario Museum. A Site Registry serves as
the primary means of collecting and maintaining up-to-date information on the distribution of
OBAR target species. The database includes information on confirmed, former, probable, and
possible breeding locations, as well as sighting records for species that are considered critically
endangered. All location data contributed to the site registry program is strictly confidential.
Knowledge of population levels and trends is fundamental to the management and
conservation of biodiversity. Yet, measuring thousands of birds on such a large-scale is virtually
impossible. None of these methods is completely accurate, but they can reveal general
patterns, and together they provide evidence that there are fewer songbirds today than there
were 40 years ago.
Swainson’s Thrush captured in mist net —
Photo: Scott Gillingwater
Researcher conducting audio and visual
point count survey — Photo: OMNR
Introduction 9