Developing Conservation and Forest Management Guidelines for Canada Warblers in the Atlantic Northern Forest
Steven D. Faccio1, J. Daniel Lambert1,
Jameson F. Chace2, and Leonard J.
1 Conservation Biology Department, Vermont
Institute of Natural Science, Woodstock, VT 05091
2 Environmental Studies Program, Department of Biology, Villanova
University, Villanova, PA 19085
3 Natural Science Department, Plymouth State University, 17 High
Street, Plymouth, NH 03264-1595
sfaccio at vinsweb.org
dlambert at vinsweb.org
jameson.chace at salve.edu
leonr at plymouth.edu
The Canada Warbler (Wilsonia
canadensis) is a neotropical migrant songbird that winters in
South America and breeds in the northeastern United States,
southeastern Canada, and in boreal forests extending west into
Alberta. In the Atlantic Northern Forests of New England, the
species inhabits a variety of upland and lowland habitats,
including red maple swamps, northern white cedar swamps, mixed
forests, and lowland spruce-fir forests (Conway 1999). Despite its
apparent wide tolerance of habitat types, the species is patchily
distributed, typically at low densities, throughout the Northeast,
which comprises a significant portion of its global range. In
addition, Canada Warbler has exhibited steep population declines,
with trend estimates ranging between -2.4% (Rosenberg and Hodgman
2000) and -13.2% per year (Faccio et al. 1998).
Responding to these data, the Northeast Endangered Species and
Wildlife Diversity Technical Committee, Partners in Flight, and the
North American Bird Conservation Initiative (NABCI) recently
identified Canada Warbler as one of the region’s highest
priorities for conservation and research (Therres 1999, Rosenberg
and Hodgman 2000, USFWS 2003). A recent study in Vermont showed
that Canada Warblers are sensitive to small changes in the forest
canopy, responding positively to ice storm-created gaps in the
Green Mountain National Forest (Faccio 2003). Additionally, recent
support from the Sweet Water Trust enabled the Vermont Institute of
Natural Science (VINS) and collaborator Dr. Jameson Chace
(Villanova University) to take an initial step in quantifying the
habitat requirements of the Canada Warbler (Faccio and Chace,
unpublished data). However, since the species utilizes a variety of
forest types, the need for additional breeding-ground research
comparing reproductive rates among vegetation types is acute. Such
an investigation is necessary to identify land protection
priorities and develop stewardship guidelines that promote nesting
In 2003, VINS and Dr. Jim Chace initiated a collaborative
project with Dr. Leonard Reitsma (Plymouth State University), to
continue investigations of the habitat requirements and breeding
biology of this little- known neotropical migrant. Data were
collected on behavior, territories, and productivity from nearly 50
Canada Warblers at 3 study sites located in New Hampshire and
Vermont (Fig. 1). Field studies in New Hampshire were conducted at
the Canaan Town Forest, and the abutting Bear Pond Natural Area
(which was recently conserved with funds from the Sweet Water
Trust). In Vermont, field work focused on the Nulhegan Basin
Division of the Silvio O. Conte National Fish and Wildlife Refuge
in the town of Lewis. These study areas total over 27,000 acres and
contain a variety of managed and unmanaged habitats. The
project’s specific conservation goals are to:
- Describe and compare Canada Warbler habitat requirements among
different forest communities.
- Determine which habitat characteristics promote nesting
- Identify priority habitats for conservation.
- Evaluate the potential for forest management to produce
favorable breeding conditions.
- Develop a set of best forest management practices for Canada
- Provide outreach materials to land protection organizations,
foresters, and other natural resource professionals.
During the pilot season, three Plymouth State undergraduates
helped us collect habitat metrics from over 100 vegetation plots.
We also constructed a geographic information systems (GIS) database
to store, manage, and display the information. Preliminary data
analysis is focused on comparing habitat composition and structure
at occupied territories vs. unoccupied sites, and at successful
territories vs. unsuccessful territories. Results of this analysis
are pending, but our predictions, based on hundreds of hours of
observation, are that Canada Warbler abundance and productivity
will be positively associated with high shrub density, semi-open
canopy, and moist soil.
The collaborators on this project are continuing the
investigation during the 2004 breeding season:
- capture and color-band 20-30 males as they arrive on territories in both managed and unmanaged habitat;
- recapture or resight males returning from the previous breeding season;
- age males based on plumage characteristics;
- document each male’s movement and behavior during six continuous, 30-minute observation periods between 25 May and 10 July;
- determine the reproductive status of males at three stages of the breeding cycle (pairing, nesting, fledging);
- delineate territory boundaries based on geo-referenced positions of observed males, collected at 5-minute intervals;
- verify accuracy of territory-mapping method with radio-telemetry;
- measure over 40 habitat variables on four plots within each territory and on paired plots located in unoccupied habitat;
- maintain a geographic information systems database to manage the information.
Once the field season is complete, we will employ standard
statistical procedures to determine which habitat characteristics
underlie patterns of distribution, abundance, demographic
structure, and rates of pairing, nesting, and fledging success.
Results of this analysis will be used to:
- describe Canada Warbler habitat requirements;
- determine which habitat characteristics promote nesting success;
- identify priority habitats for conservation;
- recommend stewardship practices that promote favorable breeding conditions.
Stewards of the three study areas (the Canaan Conservation
Commission, Mascoma Watershed Conservation Council, and US Fish and
Wildlife Service) support this work and have expressed interest in
using the results to better manage their holdings for Canada
Warbler and other songbirds. We also plan to advise conservation
and natural resource professionals throughout the Northeast on how
to meet the breeding requirements of this vulnerable species. This
will be achieved through development of two outreach products which
will be distributed directly to conservation groups, as well as to
public and private land managers. These products will consist of a
technical report detailing our methodology, results and
recommendations, as well as a concise pamphlet highlighting best
management practices that will meet the breeding requirements of
this vulnerable species. Additionally, information will be
disseminated to ornithologists and conservation biologists through
submissions to peer-reviewed journals, conferences, and
participation in professional meetings, including Partners in
Flight, NABCI, and Important Bird Areas.
Results of the field study will focus limited conservation
resources on areas within the Atlantic Northern Forest that have
high ecological value for the Canada Warbler, as well as for other
species that share its habitat. In addition, our findings will help
timberland owners to enhance Canada Warbler breeding habitat
through specific management prescriptions. Finally, this research
will build a foundation for future studies of Canada Warbler that
will enable refined approaches to the species’
Conway, C. J. 1999. Canada Warbler. In The Birds of
North America, No. 421 (A. Poole and F. Gill, eds.). The Birds of
North America, Inc. Philadelphia, PA.
Faccio, S. D. 2003. Effects of ice storm-created gaps on forest
breeding bird communities in Central Vermont. Forest Ecology and
Faccio, S. D., C. C. Rimmer, and K. P. McFarland. 1998. Results
of the Vermont Forest Bird Monitoring Program, 1989-1996.
Northeastern Naturalist 5:293-312.
Rosenberg, K. V., and T. P. Hodgman. 2000. Partners’s In
Flight Landbird Conservation Plan: Physiographic Area 28: Eastern
Spruce-fir. Version 1.0. American Bird Conservancy, The Plains,
Therres, G. D. 1999. Wildlife species of conservation concern in
the Northeastern United States. Northeast Wildlife 54:93-100.
US Fish and Wildlife Service (USFWS). 2003. North American Bird
Conservation Initiative: Bird Conservation Region Descriptions.
Division of Bird Habitat Conservation, Arlington, VA.
Figure 1. Location of Canada Warbler study sites in Vermont and
New Hampshire. Click location to view detail map.