Australian Journal of Ecology (1980), S, 1-7 Flowering phenology, seed set and bird pollination of five Western Australian Banksia species ROBERT J. WHELAN* ALLAN H. BURBIDGE Zoology Departmenl, Universilv of Western Australia, Nedlands. Australia 6009 Botany Department, University of Western Australia, Nedlands, Australia 6009 Abstract Flowering phenology and seed set characteristics of five species o/Banksia were .studied in relation to the nectarivorous birds which feed at their inflorescences. Within the Banksia woodland at the study site near Perth, the flowering sea.sons of the Banksia species were sequential and only slightly overlapping, providing a year-round nectar source. Although honeyeaters visited alt five species, seed set was very low in each case. Caging experiments indicated that, in B. atlenuata at least, alternative pollinators may plav a more important role in pollination than do nectar-feeding birds. It is suggested that non-avian pollinators, predatory insects, and characteristics of the breeding system may also have been important in the evolution of the observed flowering phenology and patterns of seed set. Introduction The genus Banksia (Proteaceae) is generally considered to be bird-pollinated (Morcombe 1968; Paton & Ford 1977; Clifford & Drake In press), yet little is known of the precise interactions which occur between these plants and the animals which visit their flowers. Tbe present study investigates the relationship between a suite of nectarivorous 'Present address: School of Plant Biology, University College of North Wales. Bangor, Gwynedd. Wales. birds and several Banksia species. Firstly, the flowering phenology of each Banksia species was documented to obtain an estimate of the availability of nectar to potential pollen vectors. Secondly, interactions between the honeyeaters and Banksia trees, and seed patterns were investigated in order to elucidate the role played by nectarivorous birds in the reproductive biology of Banksia. Study site All observations were made within the Univer- sity of Western Australia's Marsupial Breeding Station which is approximately 25 km south of Perth. Western Australia at 32°10'S. 115°50'E. This reserve is on the coastal sandplain, at the boundary of the Bassendean and Spearwood Dune Systems {McArthur & Bettenay 1960). The vegetation is predominantly Banksia woodland (mainly B. menziesii and B. attenuata) with jarrah (Eucalyptus marginata) as a codominant on the higher dunes. In the lowest areas, which are normally inundated in winter, B. Httoralis occurs in dense stands, often as the only tree species. The common nectar-feeding bird species in this area are listed, inter alia, in Table 1. Methods Flowering times were assessed by counting the numbers of inflorescences on thirty randomly selected trees of each species at 3- to 5-week intervals. The proportion of flowers which set seed was estimated for each species by collecting inflorescences from many trees and scoring for flower number. In addition, all inflorescences from the previous flowering season from at least twelve trees of each species were harvested and scored for number of mature follicles. 0307-692X/80/0300-0001 $02.00 © 1980 BlackwcU Scientific Publications 1