Discussion
In this study, we found that the eggshells of four of the five species
of Apteryx (Brown kiwi, Rowi, Roroa, and Haast tokoeka) were
different enough to be assigned to their corresponding species using
morphological characters. Whether these differences are due principally
to phylogeny or ecology is debatable. Some of the species have suffered
severe contraction to their ranges and all individuals left remain in a
single population (i.e. Rowi and Roroa). Eggshells’ characteristics
within a species (i.e. chickens) are known to be affected by
environmental conditions (Rahn et al. 1982), and other studies have
shown that the characteristics we measured in this study are strongly
affected by the environmental conditions that individual birds live in
(Winkler and Sánchez-Villagra, 2006; D’Alba et al., 2017). Therefore, in
the next paragraphs we will discuss the possible ecological conditions
that could explain these characters.