The Great Barrier Island Bird Count:  July 2006

Environmental News Issue 7

This year the GBIC Trust received funding from the Department of Conservation Biodiversity Advice Fund to carry out some initial bird monitoring on Great Barrier. Although the Department carries out careful monitoring for some endangered species, such as brown teal, New Zealand dotterels and black petrels, there is no good information on the status of many other birds, such as kereru and kaka, or small things like fantails, grey warblers and shining cuckoos. Moreover, there is no published checklist to tell us exactly what species we commonly have here, or those recorded occasionally. So this is the main aim of the study: to provide some basic data on the abundance of a range of common native and introduced birds. This involves both collecting new data, and getting together the data already recorded from some areas, such as Windy Hill and Glenfern Sanctuary. The results will really come into focus in years to come, when we will have data against which to compare the changes resulting from the elimination of rats. Another aim was to build up interest in, and information about, the birds of Great Barrier, by engaging as many Barrierites as possible in the surveys.

On the first of July, fourteen Barrierites got up at dawn to start "five minute bird counts" in pre-selected places from Tryphena to Port FitzRoy. A total of 70 "five-minute counts" were made in the five main vegetation types. Actual numeric counts were also made for selected species. Small groups of birders stood on the roadside with binoculars at the ready all over the island, causing some concern amongst nearby landowners not in the know. However the activity was harmless, and resulted in some good data, which are summarised in our first Report (available on request). Thirty-six different species were recorded (including roosters, domestic geese and turkeys).

The vegetation type with the most birds was coastal paddocks, where 30 different species were recorded. The most conspicuous species here were swallows, pukeko and spur-winged plovers. The last species is an Australian immigrant, which has increased in New Zealand since it first bred at Invercargill airport in 1932. It may have reached Great Barrier in the 1980’s (does anyone out there know?). It now breeds on GBI and has a winter population of c. 60 birds. The high pukeko count (246) was mainly due to the huge numbers on the Awana flats (174), which could pose a problem for brown teal nesting in the vicinity.

The least diverse vegetation, in terms of birds, was manuka / kanuka scrub, where only seven bird species were recorded: grey warblers and chaffinches being the most conspicuous. This vegetation—Land Units 8 and 9— covers a large proportion of the island, but it is low in food resources for most birds. However, it is also successional, meaning that over time it will change into taller forest with a mixed canopy. Currently such mixed forest has between 7 and 21 species, so an increase in birds can be predicted provided that we can keep fire out of the scrub. Also, once rats are eliminated, the rate of succession from kanuka to mixed forest is likely to increase rapidly because seed predation will decline, also stimulating the bird populations.

In addition to the birds counted "on the day", later Maaka and I made counts of the grey-faced petrel burrows at Awana, where despite continued predation by feral cats, there are c. 40 nesting pairs. Craig McInman photographed a northern giant petrel in Tryphena harbour on 23 July. I was also sent records of a semi-albino morepork on Cape Barrier Road (via Karen Walker) and a big flock of goldfinches (60+) in the Medlands Valley. So, thanks to all concerned, hope to see you at the next great bird count! Don’t forget to keep sending in those records, and keep an eye open for the dead birds on beaches after storms—some interesting species can turn up (I have recorded 26 sea birds from our coastal waters that way since 1994).

Thanks to the following participants: Maaka McCandless. Ezra Kendall. Des Casey. Burt Vowden. Deborah Mayson. Fenella Christian. Peter Edmonds. Emmy Pratt. Halema Jamieson. Alan Phelps. Colin Griffiths.