Appendix D_Shorebird_survey_report_Final_Jul20_jans edits

Appendix 4: Non-shorebird population trends

In addition to the extensive data attained for shorebird species frequenting the estuary, the SSG also
captured considerable insights into the long term abundance and biodiversity of a range of other bird
species observed within the survey area including terns, gulls, water birds, wading birds and raptors. This
section presents those findings.

On average tern numbers, together representing up to 85% of all individual birds by number recorded in
any given survey, declined by 35% between the early and later years of the survey. Not unlike long term
trends in shorebird abundance, declines amongst migratory tern species (-48%), was significantly more
pronounced than amongst resident terns (-10%), indicating possible adverse influences at a trans-national
level as compared to regional or localised factors.

                            Table 9: Average tern count declines – 2007 to present 29

     Group                                             Annual average                   Annual average                    % Change
                                                         2007-2011                        2015-2019
     Migratory Terns                                       5,189                           2,703                             -48%
     Resident Terns                                         525                             473                              -10%

     All Terns                                                5,714                           3,176                          -35%

Diagram 4 and 5 provide times series and (linear) trends for survey counts of migratory and resident tern
groups. Population declines amongst migratory terns were due almost entirely to declining abundance of
principally the Common Tern, and to a lesser degree the Indo-Pacific Little Tern. The Common Tern is a
non-breeding visitor to the eastern seaboard of Australia from its breeding grounds in Siberia and very
occasionally North America. The Little Tern meanwhile is dispersed globally with distinct populations
known to breed and migrate within Australia and from Eurasia.

Amongst resident terns, the abundant Greater Crested Tern, represents over 90% of all resident tern
numbers. Seasonality witnessed in the resident tern trend series data highlights regional movements of
the Greater Crested Tern during breeding season.




A pair of Greater Crested Terns with their distinctive lemon yellow bills, captured at rest in the estuary. The distinctive black cap extending over
the eye of the individual at rear indicates breeding status. The Greater Crested Tern is a resident of Australia and was observed in every survey
conducted. Credit: Jill Dening



29
     Due to insufficient survey data between October 2005 and September 2007 (see Appendix 1), those time series have been removed.

Noosa River – Shorebird Survey Report 2019                                                                                                 Page 22