Five-minute bird counts resurrected on Mana, April 2021


Earlier this year Colin Miskelly produced a proposal to resurrect the 5-minute bird count surveys on Mana. The island is the focus of one of the most comprehensive ecological restoration programmes in New Zealand. However, there is little information published on how the landbird community on Mana has changed over time.

The last farm stock were removed in 1986, and more than 500,000 trees and shrubs have been planted since then. This has changed the predominant land cover of the island from rank grass to forest and shrubland. Eight landbird and waterfowl species have been successfully translocated to Mana Island since 1988.

Landbird and waterfowl species translocated to (and established on) Mana Island
 
Species                                                       Date introduced
Rowi / Okarito brown kiwi                         2012
Pāteke / brown teal                                      2000–01
Takahē                                                            1988–91 and ongoing
Kākāriki / yellow-crowned parakeet        2004
Korimako / bellbird                                     2010 & 2012
Pōpokatea / whitehead                               2010
Toutouwai / North Island robin               1995–96
Mātātā / fernbird                                         2019
 
The only New Zealand sites to have received more successful bird translocations (in terms of the number of species established) are Tiritiri Matangi, Zealandia, and Kapiti Island. In addition, tūī naturally recolonised Mana Island in 2009, and are now abundant. Colin notes, however, that there is no published information on the current status of those bird species that were present on  Mana Island before ecological restoration commenced, or how the landbird community has changed over time.
 
Counts of diurnal landbirds will be undertaken on Mana Island during 2021–23. This started with the marking of a network of 20 permanent bird monitoring sites in early 2021. Regular counts of birds at these sites are planned for late April 2021. Counts will be undertaken by experienced or trained FOMI and Birds New Zealand members. Most will be completed during FOMI working weekends, with count months selected to allow comparisons with an earlier series of counts undertaken during 1987–93, and also with a concurrent series of counts being undertaken on Kapiti Island during 2021–23.
 
Five-minute bird counts do not provide a measure of bird abundance or density. For example, they cannot be used to estimate how many kākāriki there are on the island. However, they do provide a measure of conspicuousness that is closely linked to visitor experience (e.g. providing a measure of how many kākāriki you are likely to see or hear if you spend an hour on the island). The indices derived for each species can be compared over time and between sites.
 
For a local example of how the counts can be analysed and presented, see Miskelly, C.M. 2018   Changes in the forest bird community of an urban sanctuary in response to pest mammal eradications and endemic bird reintroductions.  Notornis 65: 132 – 151. It describes the changes that occurred in the bird community at Zealandia as a result of the fence being built, pest mammals eradicated, and endemic birds reintroduced to the site.