Seasonal Harvesting Corridors & Diplomatic Transit: Nomadic Transhumance Under Customary Law

1. The Science of Seasonal Transhumance: The Six-Season Cycle

Seasonal transhumance across the Bibbullmun territory was not random wandering; it was a highly organised, scientifically calculated ecological movement coordinated with the six phenological seasons (Koorlang).^[1] Over tens of thousands of years, traditional custodians optimized caloric acquisition by moving between the coastal plain, river valleys, and inland granite plateaus in precise synchronization with biological resource booms.^[2] From the estuarine fishing runs of late summer (Bunuru) to the inland root digging of late winter (Djilba), human movement was structured to harvest abundance while allowing harvested environments time to recover.^[3]

2. Arterial Transit Corridors: Songline Highways

Transhumance moved along established arterial transit corridors that functioned as the continental highways of south-western Australia.^[4] These pathways followed topographically optimal routes—contouring along river terraces, avoiding dense impenetrable scrub, and linking reliable freshwater springs (gabba-koorliny) spaced at regular day-march intervals.^[5] Many of modern Western Australia's major highway arteries—including the Albany Highway crossing the Darling Scarp and the South Western Highway—follow the exact cartographic alignments of ancient Bibbullmun walking tracks surveyed millennia ago by traveling clan assemblies.^[6]

3. Diplomatic Jurisprudence of Transit Corridors

Because major transit corridors inevitably crossed through multiple sovereign clan estates (kalla-boodja), customary law instituted a dedicated jurisprudence of international transit.^[7] Arterial paths were designated as neutral international corridors where travelers possessed guaranteed right of peaceful transit, provided they remained strictly within several hundred paces of the main track.^[8] Strangers were prohibited from setting fires, hunting large game, or gathering high-value botanical staples without obtaining permission from local estate elders. Violations of transit law were treated as hostile incursions, whereas adherence to protocol guaranteed safe passage and reciprocal trading opportunities.^[9]

4. Colonial Disruption of Transit & Ongoing Cultural Mapping

British colonisation violently fractured these seasonal corridors. Settlers erected post-and-wire fences across migratory routes, enclosed vital springs within private agricultural grants, and had police prosecute Aboriginal families who attempted to travel their ancestral pathways under colonial vagrancy and trespass acts.^[10] Despite two centuries of fragmentation, Bibbullmun elders have preserved the memory of these ancient transhumance routes. Contemporary GIS mapping projects led by Indigenous ranger corporations are recording these pathways, reclaiming them as permanent cultural corridors protected under statutory heritage and native title laws.^[11]