Study Protocol for Cerulean Warbler Atlas Project

Study Protocol

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Study Protocol

CEWAP participants chose as many sites to survey as they wished. We suggested selecting known Cerulean Warbler breeding areas, but encouraged participants to explore additional sites as well. Recording data about areas where Ceruleans are not present, but where the habitat "looks good," was also important.

Select Study Sites

First, participants selected sites to survey. State Breeding Bird Atlas (BBA), other published literature, or recent bird records were used to find appropriate sites.
Participants defined the area to be surveyed at each site. This area could be based on the extent of available habitat (for example, a riparian strip or forest patch) or on political boundaries (such as a state park or other property). Where possible, each discrete habitat patch was recorded as a separate site.
Participants located and outlined their site(s) on USGS topographic maps.
Participants created rough field maps of each site to use while surveying.

Field Surveys

Participants surveyed all the suitable habitat at a site on one or more visits. When possible, participants made visits during the morning or evening activity peaks.
On each visit, participants moved slowly through the area, noticing the approximate locations of singing Cerulean Warblers on their field maps. Females and any signs of nesting behavior were noted.
Participants used a tape recorder and a cassette tape of Cerulean Warbler vocalizations when necessary to elicit a response from territorial birds, to confirm presence or absence of the species in areas where no birds were singing, or to determine if birds were paired (females may respond to taped calls). Particpants played one (1) minute of typical song, then listened for a response. If no response was heard participants either repeated the typical song or tried one of the song variants--in some areas birds may respond better to one song type than the other.
The tape contained (on side A and B):
           1 minute typical song, 5-second pause
           1 minute typical song, 5-second pause
           1 minute first song variant, 5-second pause
           1 minute second song variant
NOTE: tapes were used sparingly; no more than 4 minutes of song (one side of the tape) were played at any one spot.
NOTE: as the tape may call in birds from great distances; participants were careful not to count the same individuals twice.
If time permited, participants searched for Cerulean Warbler nests, and noted any foraging or other behavioral observations or evidence of cowbird parasitism on Cerulean Warblers.
Remember that the goal was to estimate the total population at each site and determine breeding status.

Describe Habitats

Participants determined the extent of the forest habitat within the designated site (in acres or hectares) from topographic maps or aerial photographs.
Participants noted the general forest type, dominant canopy tree species, any obvious disturbances, and estimated canopy height (the average height of a majority of the tall trees).
For any nests found, the species of tree that it is in, nest height, and tree height were all noted, and a separate Nest Record Card was filled out.
For birds that were observed foraging or singing, the species of tree that the birds were observed in was noted and the range of heights used in each type of tree recorded; detailed notes on foraging or other observed behaviors were recorded in the Comments section or on separate sheets.

Population Status

This section of the Data Form was used to record the historical status of the site (if known), specific information about site visits, a population summary, and a breeding summary. The following modified BBA codes under the Site Visits section were used:

Possible Breeding

X	Cerulean Warbler observed in possible nesting habitat, no other indication of breeding noted
S	Singing male present (or song heard) on more than one date in the same place (at least one week apart)

Probable Breeding

P	Pair observed in suitable breeding habitat during breeding season
T	Bird (or pair) apparently holding a territory. Chasing of individuals of the same species designates a territory
C	Courtship, copulation, and display; agitated behavior or anxiety calls from adults suggesting probable presence of a nest or young
N	Birds seen visiting a probable nest site

Confirmed Breeding

CN	Carrying nesting material
NB	Nest building at the nest site
DD	Distraction display
ON	Occupied nest seen; adult seen on nest; or adult seen leaving or entering nest
CF	Adult seen carrying food
FY	Adult feeding recently fledged young
FS	Adult carrying fecal sac
NE	Nest with egg(s) seen
NY	Nest with young seen or heard
FL	Recently fledged young; young are incapable of sustained flight, restricted to the area around nest, and dependent on adults for food

Habitat and Site Characteristics

This section of the Data Form was used to record information about the habitat type, dominant tree species, canopy height, and any disturbance found at sites. Participants recorded information about specific nest sites and which species of trees were used by the birds for foraging and singing. Nest Record Cards were used to provide information about individual nests.

The final report, "An Atlas of Cerulean Warbler Populations," is now complete and has been submitted to the USFWS.

Cerulean Warbler Atlas Project
Cornell Lab of Ornithology
159 Sapsucker Woods Road
Ithaca, NY 14850

Phone: (607) 254-2465
Fax: (607) 254-2415

e-mail: forest_birds@cornell.edu