When should monitoring be conducted?

ERDC TN-DOER-E17

September 2004

protocol will be peer-reviewed by monitoring experts associated with the North American Bird

Conservation Initiative (NABCI) Monitoring Working Group chaired by Dr. Jon Bart (USGS).

When should monitoring be conducted?

Early season counts may offer the best population estimate; however, nesting birds are usually

asynchronous, therefore counting only nests may underestimate the population. Timing of sur-

veys will also be impacted locally by flood events and other weather conditions. Perhaps the

standardized method may need to require both an early and mid/late season survey. Current dis-

cussion assumes that monitoring will be conducted annually.

Further discussion established the need to clearly state population-wide objectives for ILT

monitoring efforts (i.e., meet objectives of the Recovery Plan), state local survey objectives (i.e.,

conserve ILT populations in specific Corps projects), and establish a population-wide monitoring

plan and protocol that can be established at the national level.

How should productivity be measured?

Several issues were raised concerning the importance of measuring productivity and how it can

be standardized. The following were major points that need to be investigated:

Assess the relative merits of frequent visits to a colony (once a week or more frequently)

to estimate productivity using survival analyses versus infrequent visits (as few as two per

season) to provide productivity indices. Habitat quality often varies considerably among years,

and even within a season, because of factors like flood events and plant growth. However, birds

may become stressed if visits occur too frequently.

Compatibility among data derived via differing procedures should be evaluated relative

to different objectives for analyses of productivity data. Some projects measure the number of

fledglings per breeding pair (FBR); however, few areas are collecting this data and methods are

inconsistent. Timing is very important when counting fledglings, because young will move

around more as the season progresses.

Measure egg and chick survivorship with some type of survival analysis (e.g.: Mayfield

method).

The term "fledging" needs a specific definition and should be measured consistently.

Usually, the definition of a fledgling is a young bird that is easily discernable from adults, is

greater than 15 days old, and can sustain flight for relatively long distances.

Detectability of nests and young must be considered when assessing productivity.

Demographic models should be designed to allow effective use of range-wide productiv-

ity data.

How should habitat be monitored?

Compose a set of explicit questions regarding habitat and develop hypotheses that

address those questions, then design experiments to test those hypotheses.

Coordinate experiments among regions (Corps Districts) in order to draw more general

conclusions.