LONG-TERM CHANGES IN THE RELATIVE ABUNDANCES OF BIRDS IN KINGS PARK, PERTH, WESTERN-AUSTRALIA

D.L. Serventy censused birds in Kings Park, Perth, between 1928 and 1937 and again between 1952 and 1955. Abundance was estimated by the frequency with which species were detected on censuses. The counts were repeated in 1986 by H. F. Recher. A total of 44 species were recorded during censuses. Since the first counts, were made, 14 species decreased in abundance by more than 15%, and 9 species went locally extinct. Eleven species increased in abundance by more than 20% (5 by more than 50%), and the abundance of 19 remained unchanged (frequency of occurrence changed by less than 15%). Although nearly 300 ha of the park's 400 ha area remains as native vegetation, this vegetation has been degraded by logging, changed fire regimes, construction of trails, and invasion by exotic weeds. Changes in the ground vegetation have had a particularly significant impact. Nine of the 16 species that declined in abundance are ground foragers. Of the species that increased in abundance, a number benefit from the greater availability of nectar, fruits, and water in the suburban gardens that have developed around the park. The Australian Raven (Corvus coronoides) has become particularly abundant and predation by ravens on nests may contribute to the decline of some species. Changes to the park vegetation, suburban development of the park's immediate surroundings, and the extensive clearing of vegetation throughout southwestern Australia appear to have had a more significant effect on the park's avifauna than the size of the park or its isolation in an urban environment. Poor management has seriously reduced the capacity of Kings Park to support native wildlife. Changes in park management designed to rehabilitate native vegetation, control weeds, and control ravens are necessary to prevent the further loss of species from the park's avifauna.