A0623
Title: Multispecies occupancy modelling of New Zealand bird species
Authors: Nokuthaba Sibanda - Victoria University of Wellington (New Zealand) [presenting]
Abstract: Birds New Zealand is undertaking the third Bird Atlas for the country, which started on the 1st of June 2019 and will end on 31 May 2024. Single species occupancy models were applied to analyse data from the previous two atlases (1969-1979 and 1999-2004) to create maps of occupancy estimates for 64 bird species. We illustrate the application of multi-species occupancy models for New Zealand citizen science data. To provide more recent estimates of occupancy, we use data from the eBird program to cover the years 2015 to 2019. eBird data were first processed to make them suitable for occupancy models and to be consistent with the NZ Bird Atlas sampling design. We focused on three species and restricted the study region to the Greater Wellington area. We considered one introduced species (Platycercus eximius) and two native species (Cyanoramphus novaezelandiae and Petroica macrocephala). Single season occupancy models were first fitted to each of the three species in turn. A spatial component was included using restricted spatial regression. Multispecies occupancy models were then fitted to pairs of species and then for all three species. All models were fitted using a Bayesian approach in the R package rStan. Logistic distribution priors were used for the model coefficients. Results were presented using maps of occupancy probabilities for each species and for different pairs of species, with presence observations overlaid.