Seasonal Habitat Shifts and Wetland Dependence of Grey Crowned Crane in Urbanising Kenya

Abstract

ABSTRACT The Grey Crowned Crane ( Balearica regulorum ) has experienced major global population declines, leading to its uplisting to Endangered status on the IUCN Red List of Threatened Species. In Kenya, the Nairobi metropolitan area supports one of the country's substantial remaining populations of this species, yet data on temporal and spatial variation in population and habitat associations remain limited. This study conducted systematic censuses at 130 sites across five counties between June 2023 and February 2024 to assess patterns in population and habitat use across wet and dry seasons. The observed crane population was estimated at 1116 individuals, based on the average of wet and dry season counts, with seasonal crude densities of 0.127 individuals/km 2 in the wet season and 0.14 in the dry season. Adults comprised 93.6% and young individuals 6.4%, with Kiambu County recording the highest proportion of young cranes (44.4%). Crane abundance varied substantially among counties and was positively associated with the availability of suitable wetland habitats. Habitat use shifted seasonally, with greater wetland occupancy during the wet season and increased use of grasslands during the dry season. These patterns highlight the species' strong dependence on wetlands and its flexible foraging behaviour in modified landscapes. Our findings emphasise the ecological value of even small or degraded wetlands and call for their integration into urban conservation and land use planning frameworks.