14.3 Monitoring
Monitoring needs to be given a high priority. Without it, we have no way of
knowing whether management is successful or needs altering. Thorough docu-
mentation is also essential if you want to inform others of the success or other-
wise of your management. It is particularly important to record negative results,
which can help to avoid the repetition of management that has already proved
unsuccessful. Unfortunately, negative results are rarely disseminated and diffi-
cult to publish. The results of monitoring which re-confirms previous findings,
but under different conditions at other sites, are also informative.
There are several levels at which monitoring can be used to determine the
effects of habitat management on birds. The simplest is to record the numbers of
birds using the area at different times (Chapter 2). The next level is also to mon-
itor the effects of management on key factors likely to influence bird use, such as
vegetation composition and/or structure or food supply (Figure 14.2). This will
help assess possible reasons for the management’s success or failure. If bird use
declines and your management is not producing the desired habitat conditions,
then you need to review the effects of your management on the habitat. If bird
use declines, but your management is having the desired effect on habitat condi-
tions, then you need to review the relationship between the desired habitat
conditions and bird use.
A further level is to compare trends in bird use and key habitat features in both
a managed and similar unmanaged area (a control) (Figure 14.3). This will help
determine whether changes in the managed area are due to the management
itself, or simply part of changes taking place over a wider area. It is still possible,
though, that any differences in trends between managed and unmanaged areas
are simply due to chance. The most rigorous level is to use a randomized, replicated
experiment to determine the effects of management. It is rarely practical to set
up such experiments on a large enough scale to investigate effects of management
on bird use. However, it is, often feasible to use randomized, replicated experi-
ments to determine the effect of management on biotic and physical factors
thought to be important in influencing bird use. For example, many species of
waders and other wetland birds feed on invertebrates in the mud (benthos) of
shallow, brackish lagoons (Section 4.10.3). We do not know whether food sup-
ply is limiting use of a particular lagoon by these bird species. However, increas-
ing the abundance of their prey is at worst likely to have no effect on bird use, and
at best will increase bird use and possibly also survival and breeding success. The
effects of organic matter on benthic invertebrate biomass in the mud can be
investigated by marking out a number of plots and incorporating organic matter
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