Periodicity in whisker δ13C and δ15N time series using wavelet analysis.

Here we report the number of isotopic time series that exhibited significant cycles either all along the length of the whiskers (at least 80% of the cone of influence (COI), which is the region of the power spectrum that is not affected by the edge effects) or only in a smaller part of the series (between 50 and 80% of the COI). Growth rate was calculated assuming that cycles were annual (see text).