cERulEAN wARblER - Appalachian Mountains Joint Venture

29 Pages·2013·14.18 MB·English

cerulean warbler

Management Guidelines
for Enhancing Breeding Habitat
in Appalachian Hardwood Forests
February, 2013
Authors
Petra Wood1, James Sheehan2, Patrick Keyser3, David Buehler3, Jeff Larkin4,
Amanda Rodewald5, Scott Stoleson6, T. Bently Wigley7, Jeremy Mizel2, Than
Boves3, Greg George2, Marja Bakermans5, Tiffany Beachy3, Andrea Evans4,
Molly McDermott2, Felicity Newell5, Kelly Perkins2, Matt White4
1 U.S. Geological Survey, West Virginia Cooperative Fish and Wildlife
Research Unit, West Virginia University, Morgantown, WV, USA.
2 West Virginia Cooperative Fish and Wildlife Research Unit, Division of
Forestry and Natural Resources, West Virginia University, Morgantown, WV,
USA
3 Department of Forestry, Wildlife, and Fisheries, University of Tennessee,
Knoxville, TN, USA
4 Department of Biology, Indiana University of Pennsylvania, Indiana,
Pennsylvania, USA
5 School of Environment and Natural Resources, Ohio State University,
Columbus, Ohio, USA
6 U.S. Forest Service, Northern Research Station, Irvine, PA, USA
7 National Council for Air and Stream Improvement, INC. Clemson, SC, USA
Recommended citation: Wood, P.B., J. Sheehan, P. Keyser, D. Buehler, J.
Larkin, A. Rodewald, S. Stoleson, T.B., Wigley, J. Mizel, T. Boves, G. George,
M. Bakermans, T. Beachy, A. Evans, M. McDermott, F. Newell, K. Perkins,
Cerulean Warbler. Bill Hubick
and M. White. 2013. Management guidelines for enhancing Cerulean
Warbler breeding habitat in Appalachian hardwood forests. American Bird
Conservancy. The Plains, Virginia. 28 pp.
Cerulean Warbler Management Guidelines...........................................................................................................i
Acknowledgments
This research was an outgrowth of the many integrated efforts of the
Cerulean Warbler Technical Group for conservation of Cerulean Warblers.
Development of this habitat management guidelines document was funded
through a grant from the U.S. Fish and Wildlife Service, (USFWS) Northeast
region Division of Migratory Birds. Funding for publication provided by
American Bird Conservancy through the Appalachian Mountains Joint
Venture. Data on which the guidelines primarily are based were collected
in a research study funded by National Fish and Wildlife Foundation,
National Council for Air and Stream Improvement, Inc, USFWS, U.S. Forest
Service (USFS) Monongahela National Forest and Daniel Boone National
Forest, MeadWestvaco Corporation, Kentucky Department of Fish and
Wildlife Resources, Ohio Division of Wildlife, Tennessee Wildlife Resources
Agency, Department of Forestry, Wildlife and Fisheries at the University of
Tennessee, The Nature Conservancy through a USFWS HCP planning grant
with the Tennessee Wildlife Resources Agency, West Virginia Division of
Natural Resources Wildlife Diversity Program, and U.S. Geological Survey
West Virginia Cooperative Fish and Wildlife Research Unit. This research
was conducted on USFS Daniel Boone National Forest and Monongahela Appalachian breeding habitat. Than Boves
National Forest, on public lands owned by the Tennessee Wildlife Resources
Agency and the West Virginia Division of Natural Resources, and on
private lands owned by Forest Land Group/Wagner Forest Management
and MeadWestvaco. We appreciate the cooperation and assistance of these
agencies/groups and the efforts of their forest management personnel for
assistance with study site selection, design of harvesting treatments, and
especially implementation of harvests. We thank cooperating universities:
Indiana University of Pennsylvania, Ohio State University, West Virginia
University, and University of Tennessee. This study was completed under
the auspices of IACUC protocols from Ohio State University (#2004A0047,
2007A0015, and 2010A0003), West Virginia University (#04-0302, 07-0303),
and University of Tennessee (#561).
Technical review of this publication was provided by: Frank Ammer, Barbara
Breshock, Gwen Brewer, Randy Dettmers, Mary Ann Fajvan, Todd Fearer,
Christine Kelly, Ben Jones, Glen Juergens, Cathy Johnson, Paul Hamel, Jim
McCann, Mike Reynolds, Ken Rosenberg, Sara Rothemel, Brian Smith, and
Scott Somershoe
Publication design and layout by Debra Reynolds, USFWS
Photos: Cover: Clockwise: Appalacian landscape, Charlie Choc; Cerulean
Warbler, Bill Hubick, http://www.billhubick.com; Fledgling, Marja
Bakermans; Shelterwood, Scott Stoleson; Female, Bill Hubick
Cerulean Warbler Management Guidelines..........................................................................................................ii
Table of Contents
Introduction..............................................................................................1
Goals...........................................................................................................2
Conservation.............................................................................................3
Cerulean Warbler Habitat Associations................................................4
Landscape and Topography.......................................................4

Stand Structure and Composition............................................6
Male Cerulean Warbler. Marja Bakermans
Cooperative Cerulean Warbler Forest Management Project..............8
Findings Relevant to Silvicultural Prescriptions..................................12
Territory Density.........................................................................12
Nest Success.................................................................................14

Habitat Use..................................................................................15
Changes in Allied Bird Communities.....................................16
Management Considerations..................................................................18

Landscape-scale Considerations..............................................18

Stand-scale Considerations.......................................................19

Temporal and Silvicultural Considerations.............................21
Summary....................................................................................................22
References Used in These Guidelines....................................................23

Cerulean Warbler Management Guidelines.........................................................................................................iii
Introduction
The Cerulean Warbler (Setophaga
cerulea) is a migratory songbird that
breeds in mature deciduous forests
of eastern North America. Cerulean
Warblers (hereafter, ceruleans)
require heavily forested landscapes
for nesting and, within Appalachian
forests, primarily occur on ridge
tops and steep, upper slopes. They
are generally associated with oak-
dominated (Quercus spp.) stands
that contain gaps in the forest
canopy, that have large diameter trees
(>16 inches diameter breast height
(dbh)), and that have well-developed
understory-and upper-canopy layers.
Ceruleans primarily use the mid-
and upper-canopy where they glean
insects from the surface of leaves and
conceal their open cup nests. Because
they are severely declining across Figure 1. Cerulean Warbler distribution and trends in abundance across their breeding
much of their range (Fig. 1), habitat range from Breeding Bird Survey data (1966-2010; Sauer et al. 2011). The Appalachian
Mountains Bird Conservation Region boundary is in black.
management is a high priority.
Management for this species can also
improve conditions for a number of
other wildlife species that depend on
the same structure.
Adult Cerulean Warbler feeding chick. Wayne Miller
Cerulean Warbler Management Guidelines...........................................................................................................1
Goals
This document provides land
managers in the Appalachian Region
with guidelines for retaining and
enhancing habitat for Cerulean
Warblers and a diverse bird
community based on the current
available science. They are intended
for use by federal, state and private
foresters, biologists, and other land
managers. These management
guidelines are based to a large
extent on the recently completed
Cooperative Cerulean Warbler Forest
Management Project (CWFMP) but
also incorporate relevant findings
from other research projects. All
literature incorporated into this
document is listed in the Reference
section. The guidelines apply
primarily to upland oak-dominated
habitats where the majority of the
research reported was completed.
Figure 2. Cerulean Warbler abundance (number per route) estimated from Breeding Bird
Survey data for the Appalachian Mountains Bird Conservation Region (BCR) (adapted
from Shumar 2009). Study areas from the Cerulean Warbler Forest Management Project
(CWFMP) are in the core range of the species.
Cerulean Warbler Management Guidelines...........................................................................................................2
Conservation
About 80% of the total cerulean population breeds within the Appalachian
Mountains Bird Conservation Region (BCR; Fig. 1), and they are particularly
abundant within the central part of the region (Fig. 2). Declines have
occurred across most of their range (Fig. 1). A range-wide loss of ~70%
of the population (Fig. 3) led to their designation as a species of national
conservation concern by the U.S. Fish and Wildlife Service (USFWS) and as a
Continental Watch List species by Partners in Flight.
Cerulean declines are primarily related to the loss and reduced suitability
of habitat on breeding, migration, and wintering grounds. On breeding Male Cerulean Warbler. Than Boves
grounds, the second growth forests that occur throughout most forested
landscapes often lack the complex forest structure favored by ceruleans.
Old-growth forests naturally develop a more open and complex canopy
structure, as well as multi-layered shrub and mid-story layers. Maintaining
older, structurally diverse forest within cerulean breeding range may be
important to sustain populations in the long-term and to support the
ecosystems on which they and other organisms depend. In managed forests,
however, foresters and landowners can use silviculture as a tool to develop
stands with structural and compositional characteristics that are favorable for
cerulean and associated species. Partial harvesting to benefit ceruleans can be
consistent with forest management goals such as promoting oak regeneration
and managing for a diverse wildlife community.
Figure 3. Cerulean Warbler population decline modeled using Breeding Bird Survey data
from 1966-2006 (W. Thogmartin, unpubl. analyses).
Cerulean Warbler Management Guidelines...........................................................................................................3
Cerulean Warbler Habitat Association
Cerulean breeding density is variable across the Appalachian region (Fig. 2).
Their distribution is often patchy in part due to the patchy nature of canopy
disturbance in mature forests and their strong association with ridge tops.
In a southern West Virginia study, for example, they occurred at 40% of
randomly placed sample points.
Landscape and Topography
Small forest tract size and the presence of large-scale edge (e.g., agricultural
lands, mountaintop mines) can limit use of a site by ceruleans. Although the
minimum forest tract size required by ceruleans to breed successfully is not
known, smaller, more fragmented forest patches tend to have lower densities
of territories and lower nest success. Ceruleans will use relatively small forest
patches (~25 ac), but typically in landscapes that are primarily forested (e.g.
>75% forest cover within ~6 miles of the project area). In landscapes with
a relatively low proportion of forest cover (e.g. those that are dominated by
Figure 4. Cerulean Warbler territories on
a topographic map of the Lewis Wetzel agriculture), ceruleans are less likely to occur within small forest tracts. In the
Wildlife Management Area, West Virginia, heavily deforested Mississippi Alluvial Valley, ceruleans require ~4000 acre
showing territories aligned along ridgelines
tracts, in the highly fragmented Mid-Atlantic region ~1730 acres, and in the
and clustering near areas of local relief.
more forested Ohio Hills ~60 acres.

Ceruleans are often associated with canopy gaps and also use internal
forest edges including narrow roads, narrow utility rights-of-way, narrow-
cut strip mines, edges of small timber harvests, and trails. However, they
are less abundant near abrupt or “hard” edges between forest cover and
large expanses of open land (e.g., commercial, residential, and industrial
development). In southern West Virginia, for example, cerulean abundance
decreased near mountaintop mine edges and in northern West Virginia, they
avoided edges of a large powerline right-of-way that was ~75 feet wide.
In the Appalachians, ceruleans primarily occur along ridges and steep, upper
slopes and appear to cluster near areas of local relief such as knobs and bluffs
(Fig. 4). The soil characteristics and topography of these features contribute
to stratification of canopy trees so that ridge top forests often have a complex
overstory structure containing large oaks with expansive crowns. Thus, ridge
top forests often offer the structure and composition sought by breeding
ceruleans. Within ridge top forests, ceruleans often favor mesic, north- and
northeast-facing slopes, although other aspects are used. In some sections of
the Appalachians (e.g. Delaware River valley), ceruleans are most dense at
lower slope positions and along major waterways.
Cerulean Warbler Management Guidelines...........................................................................................................4
Appalachian landscape. Than Boves
Minimum patch size used by ceruleans depends on the
amount of forest cover in the landscape.
Cerulean Warbler Management Guidelines...........................................................................................................5
Stand structure and Composition
Before extensive clearcutting in the
late 19th and early 20th century,
tree mortality from old age, wind-
throw, ice storm damage, and fire
contributed to the development of
structurally complex and relatively
open stands in which oaks were
dominant. In the even-aged
stands that developed following
those extensive harvests, natural
canopy disturbances tended to be
unevenly distributed and relatively
small thereby creating a relatively
homogenous canopy structure
(e.g., a closed canopy forest with an
undeveloped understory and/or mid-
story).
Important Components of Cerulean
Habitat
Large Diameter Trees
Ceruleans place territories and nests
in hardwood forests with well-
spaced, large diameter trees (>16
inches dbh). Nests are typically in the
largest trees available at a site.
Canopy Gaps and Structure
Ceruleans favor the complex canopy
structure characteristic of uneven-
aged stands and old growth forest.
Canopy gaps allow mid- and upper-
canopy trees the growing space to
form long horizontal branches and
Upland forest used by Cerulean Warbler. Marja Bakermans
develop dense foliage. Tree species
composition is relatively diverse with
shade-intolerant species abundant in Heterogenous stand structure including large trees,
the overstory. canopy gaps, and understory vegetation promote
density and reproductive success of ceruleans.
Cerulean Warbler Management Guidelines...........................................................................................................6