Brown Teal holding on to the Barrier: Statistics suggest the Pateke have a fighting chance by John Ogden

Environmental News Issue 20 Spring 2009

Since Hutton’s list in 1868, the birds of Great Barrier Island have changed drastically. At least 12 species have gone extinct on the island, and we have gained a further 25 introduced species. Some native species are left with critically low populations, which are highly vulnerable to predation or habitat change through drainage and the spread of exotic weeds in wetlands. Tomtit and kakariki fall into the first category, while bittern, spotless crake and fern-bird are in the latter. On the shore the “Nationally Vulnerable” New Zealand dotterel has shown a slow decline since counts began in 1998, and the current population is only c. 50 birds – perhaps 15 nesting pairs – for the whole island. Likewise, the nesting population of black petrels on Hirakimata has shown a steady decline. The current population may be c. 4000 birds, but the rate of decline averages 122 birds per year!
However, one iconic species, which seems to be hanging on is the brown teal or pateke. Numbers certainly declined since from the mid 80s to c. 2000, but since then total counts seem to have crept up slightly (see Figure). The results are difficult to interpret, since counts are made at recognised flock sites (only) each year, and the numbers not present at the flock sites cannot be assessed. However, a positive trend is certainly better than a decline! As most of the pateke on the island are in the Okiwi basin, where serious DOC research commenced in 2000, it looks like the DOC have been doing something right! We should all congratulate them on this work.
Having said that – the sad truth is that there is still a long way to go to turn things around for the biodiversity overall.