One of the fully enclosed transfer stations had an average of
1176 total birds using the facility per survey, more than 6 times
higher than the mean number of total birds using the other fully
enclosed transfer stations. In addition, the semi-enclosed transfer
station in California had an average of 630 birds using the
facility per survey, more than 7 times higher than the mean number
of total birds using the other semi-enclosed transfer stations.
The reasons for such high levels of bird use at these 2 waste
transfer stations are unknown. Because these individual transfer
stations had an overriding influence and biased the data, the bird
observation data from these 2 facilities were removed prior to
analyses.