Pied Flycatchers
Sanz (2001) examined the nesting behavior and success for male and female pied flycatchers (Ficedula hypoleuca). He hypothesized that males would be more involved in nesting activities as the level of brood demand increased and as the attractiveness of the male decreased. The author manipulated brood demand by removing two eggs from randomly selected nests and placing these eggs into other randomly selected nests. This created two levels for a clutch-size manipulation factor – reduced and enlarged clutch sizes. A third level consisted of nests where the number of eggs was not manipulated (called the “control” level). The author manipulated the attractiveness of the male by reducing the size of the white patch on the forehead. The forehead patch was reduced in size on randomly selected males by clipping approximately two-thirds of the white feathers. Thus, the experiment consisted of two levels of the forehead patch factor – unmanipulated and reduced. In one aspect of the experiment, Sanz recorded the feeding rate of the male flycatchers on the 13th day post-hatch. The feeding rate was recorded as the number of times the male fed the hatchlings per hour.
The results of the study are in PiedFlycatcher.csv (data, meta). Download these data, load them into R, order the levels for the clutch size manipulation variable so that the “control” group is in the middle (see this), and prepare a complete analysis that follows the workflow and tenor of the example analyses in the reading.