Methods - Michigan Breeding Bird Atlas Website

Methods
The Second Michigan Breeding Bird Atlas
chosen as priority blocks; in the NLP, two of the four blocks in a township were
randomly selected; and only one block was randomly selected in the UP. These decisions
were based primarily on the availability of volunteers in the different regions of the state.
Because of the difficulty of achieving coverage goals in MBBA I, fewer priority blocks
were used in MBBA II: A single priority block was chosen in each township, regardless
of the region. To facilitate comparisons between the Atlas projects, the MBBA II priority
blocks are a subset of those used in MBBA I. Therefore, while a priority block was
randomly selected out of the four possibilities per township in the SLP, there were only
two possibilities per township in the NLP and one possibility per township in the UP. A
secondary block was selected in each township for MBBA II in roughly the same fashion.
Observers were directed to survey the priority blocks first. If they were unable to travel
to a more distant priority block, the secondary and non-priority blocks could be surveyed.
Thus, data from all blocks were accepted, regardless of priority status, with the additional
coverage expanding our knowledge of species-specific distributions. Because block
coverage was unequal in MBBA II and MBBA I, results have been compiled by township
to facilitate comparisons within and between Atlases.
Coverage Goals
A major objective of the field work portion of MBBA II was to adequately cover each
priority block. As in MBBA I, a minimum count of 50 species was used to signify an
adequate level of coverage (McPeek and Adams 1991). This was an internal quality
control measure and surveys were never cut short at this number. While blocks in some
habitats (urban centers, agricultural areas, and deep forest) might not reach 50 species,
this measurement was useful in identifying locations in need of additional coverage. In
addition to number of species, coverage can be described by field hours (effort) and by
the number of records obtained. While these metrics had no defined goal, they provide a
useful summary of coverage information for MBBA II. The standard Atlas forms are the
casual card, the point count form, and the survey checklist form. Effort was collected on
two forms: The point count protocol stipulated that observers spend five minutes at each
point, so a standard 25-point survey counted as approximately two hours, while the
survey checklist asked for hours spent in the field. Each species listed on a form was
considered a record.
While effort seems a very straightforward measurement, the number of hours needed to
cover a block varies with the skill of the individual observer. How observers recorded
and perceived their time spent in a block also varied. Surveys from volunteers which did
not include time were assigned field hours at the rate of one hour per 30 species reported.
Because data on hours were not available from MBBA I, no comparisons can be made in
terms of hours of effort with MBBA II.
© 2012 Kalamazoo Nature Center
4 of 14