Artificial Bird Nests Have Been Used Extensively When Studying Predator

Essay

Artificial bird nests have been used extensively when studying predator behavior.
Biologists have assumed predators will find and respond to artificial and natural nests in the same way. In a study to test this assumption the predation of 27 American
Robin (Turdus migratorius) nests and 27 artificial wicker-basket nests were
compared. Artificial nests were placed 30m from existing robin's nests in a randomly
chosen direction. The natural nests and artificial nests were checked at 5-day
intervals, and the number of nests (out of 27) that had been disturbed by predators in
the interval was noted. The results are as follows: $$\begin{array}{l}\text { Numbers of real and artificial Robin nests predated }\\\begin{array} { | l | c | c | c | } \hline \text { Nest type } & \begin{array} { l } \text { 5-day } \\\text { check }\end{array} & \begin{array} { l } \text { 10-day } \\\text { check }\end{array} & \begin{array} { l } \text { 15-day } \\\text { check }\end{array} \\\hline \text { Natural } & 12 & 17 & 19 \\\hline \text { Artificial } & 3 & 12 & 18 \\\hline\end{array}\end{array}$$ (a) Using a single set of axes, construct time series plots for (a) the number of natural
nests disturbed by predators and (b) the number of artificial nests disturbed by
predators.
(b) Does it appear that the artificial and natural nests have the same pattern of
predation through time? Justify your answer by appealing to specific aspects of
your plot in part (a).