Although the literature on ethnicity is vast, studies have typically focused on minority groups, with white majorities, including Europeans in Aotearoa New Zealand, surprisingly absent. Demographic changes, however, and the decline of majorities, are altering politics and making white ethnicity more salient. (Re)assertions of dominance such as Brexit and the storming of Capitol Hill, and white nationalist violence such as the Christchurch mosque terror attacks, all illustrate the growing need to understand structures and processes of majority identity. Recognising this gap, this study examines changing patterns of identification within the European population in the New Zealand census. To do so it uses the novel New Zealand Longitudinal Census (NZLC) dataset, which links individuals across censuses, offering an unprecedented opportunity to examine whether and how individuals change their ethnic affiliations over time. The study adopts a critical demographic conceptual framework, incorporating insights from diverse fields including social constructivism, critical whiteness studies, and a growing literature on settler colonialism. Census counts are fundamentally political, with clear implications for policy and resource distribution, and offer a rich context for exploring the structure of majority ethnic identity. Existing census-based studies, though focused generally on minority groups, have demonstrated clearly how censuses form a key site in the social construction of ethnicity and ethnic groups. The study is in two main parts. The first part considers what patterns can be observed in European identification over the five censuses held between 1991 and 2013. This broad analysis – over two decades of remarkable social and demographic change – finds that Europeans have generally had the lowest level of ethnic response change of any of New Zealand’s major ethnic groups. This contrasts sharply with the fluidity observed between and within other groups, particularly Māori and Pacific peoples. The second part focuses on an exception to this general pattern of European stability, shifts to ‘New Zealander’ ethnicity by Europeans in the 2006 census. It considers the factors associated with this one-off shift to national naming and the broader relationship between national identity and majority identity. Regression modelling shows that claims to New Zealander ethnicity were far from random. Rather it was a phenomenon significantly correlated with being male, being middle aged, having a post-secondary education, living in a solely European household, and in areas with a higher proportion of Europeans and lower levels of deprivation. These characteristics, and the ‘race-like’ stability of European ethnicity, suggests power and dominance play a key role in structuring majority ethnic claims, and offer further evidence of ethnic counts as illustrative of both the individual and the society that produced them.