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Methods
Because we are attempting to examine the entire state of Arizona, it is not possible to
survey every patch of potentially suitable Yellow-billed Cuckoo habitat. To overcome this
obstacle we reviewed historical accounts of Yellow-billed Cuckoos within Arizona and based
much of our survey site selection upon these records. Additional sites have been selected
where sufficient habitat exists, and where it appears suitable for Yellow-billed Cuckoo
occupancy. We have equally subdivided the state, with the Arizona Game and Fish Department
(AGFD) surveying the southern
half and the USGS Colorado Plateau Field Station (CPFS) surveying
the northern half for Yellow-billed Cuckoos. The USGS Tucson Sonoran Desert
field Station (SDFS) randomly selected bird locations, and intensively measured vegetation variables in
order to predict if the bird is selecting specific vegetation types throughout Arizona.
All personnel involved in this project participate in survey techniques training. This
3-day event occurs in June and is jointly sponsored by the Kern River Research Center
(Weldon,
California), AGFD and
CPFS.
The survey methodology used in this project has been modified from the foundation work
of Halterman (1991) and Laymon (1998,
unpublished). We have developed a Survey Data Form that has been
standardize for all surveys in California and Arizona.
Survey Methods:
1) the surveyor uses playback of a taped recording of the paired yellow-billed
cuckoo’s contact call ("kowlp" call, see "the bird" section of
this site for a sample of this call). Playback equipment must be capable of projecting the
"kowlp" call at least 100 meters with a minimum of distortion.
2) Surveys are conducted between the hours of 6:00 AM and noon. Surveys are terminated
if shade temperatures exceed 100 degrees F (38 degrees C) or
during steady rainfall.
3) One transect is made through the habitat for every 200 meters of habitat width.
4) The surveyor initially approaches the beginning of the transect and remains quiet
for a 2-minute period to acclimate to the ambient noise and to listen for
spontaneously-calling cuckoos.
5) If no cuckoos are heard then the surveyor plays the "kowlp" call once,
followed by one minute of silence to listen for response. If no detection occur, this
playback-listen technique is repeated an additional four times. The surveyor then moves
100 meters along the transect and begins the listen-playback-listen protocol again.
6) Responses to the playback of the "kowlp" call will generally take one of
three forms. A bird may respond from a distance with a vocalization, it may fly in quietly
and vocalize closer to the observer, or it may fly in quietly without vocalizing. The
interpretation of these behaviors forms the basis for determining breeding status.
7) In addition to documenting cuckoo detection's and behaviors, surveyors collect
information about habitat composition and structure, and also record other bird species
detected during the survey.
Utilizing the above methodology and survey form, during 1998 a
total of 77 sites were surveyed by the Arizona Game and Fish Department (AGFD), Colorado Plateau Field
Station (CPFS)
and cooperators. AGFD,
CPFS and our
cooperators will visit at least 107 sites in 1999, including repeat visits to several of
the more productive sites from 1998. Each site will again be visited once during the
survey season (June 15-August 30). However, for validation purposes, a subset
(approximately 15%) of the sites will be surveyed an additional 2 times, for a total of 3
surveys, with each visit separated by a minimum of 10 days. This will allow us to test the
relative effectiveness of the single-survey protocol verses the standard 3-time survey
suggested by Halterman and Laymon (pers. com.).
Click Here for a List of Survey Sites.
Survey techniques, data collection and analysis, and data archiving for this project
have been standardized so that everyone collects the same information and can access each
other’s data. In addition, Data Summaries are provided for
public access within this web site. These summaries will be updated bi-weekly throughout
the 1999 Yellow-billed Cuckoo survey season.
View The Survey Data Form used by
Researchers
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