ABSTRACT. – Analyses using the spatial frequency of species occurrences, as obtained by faunal atlases, allows us to obtain information on assembly rules of local bird assemblages. Here, diversity/dominance diagrams have been used to relate the structural differences in two phenology-based assemblages (i.e. sedentary species and long distance migrants) obtained by an occurrence data set throughout a local breeding bird atlas in an Apennine nature reserve of Central Italy. Among the 58 breeding bird species sampled, 28 % were long distance migrants. On the average, long distance migrants were spatially rarer when compared to sedentary species. In diversity/dominance diagrams, sedentary species show a trend similar to that obtained by the entire community (broken-stick pattern), while long distance migrants have a curve with slope tending to fit geometrically. Geometric species models show steep plots and are typical of assemblages with high relative dominance, low evenness and few species (in our case, the long distance migrants). Moving from geometric series towards a broken-stick model, the assemblages tend to be even more species rich (in our case, the sedentary species). In a Palearctic bird community, long distance migrants are generally rarer in abundance and spatial distribution when compared to sedentary species. A different phenology may imply differences in species evolution, history and ecology with consequences for abundance, distribution and rarity patterns. In our study area, patterns of spatial occurrences evidenced by diversity/dominance curves may be due to the influence of long-term history, short-term competition and local disturbances that differentiated the two phenologic sub-assemblages.