Birds of the Routeburn Track 1980 & 2018

[Colin Miskelly]

Kia ora

Kate & I walked the Routeburn Track 21-23 Dec 2018, nearly 39 years since I previously walked it 2-4 Jan 1980. The entire track now has a stoat trap line along it. While a few endemic species are apparently more abundant than they were 39 years ago (notably kaka and robin), most have yet to respond to predator suppression. Parakeets, riflemen, mohua, fantails and tomtits were in much lower numbers than in 1980, with mohua recorded only on the Routeburn flats (they were on both sides of the divide in 1980). While my ability to detect riflemen has declined (I now use the collective noun ‘a silence of riflemen’) Kate can still hear them, and so I suspect the decline is real.

One striking difference that was bigger than the Routeburn Track was the number of falcon that we encountered. I did not record a single falcon during 4 weeks in the South Island in 1979-80 (they were a bogie bird for many years), but we had three encounters (4 birds) between our cabin in Glenorchy and the start of the walk on 21 Dec 2018, as well as the 2 on the track later that day (and another 3 falcon encounters on the West Coast, near Arrowtown and on the Milford Track before and after the Routeburn). Surely falcons are much more abundant in the South Island than they were 40 years ago.

In the list below 1980 figures are in parentheses. Both datasets are given in more detail in eBird (i.e. in shorter sections, rather than totals for the entire track).

Paradise shelduck 11 (15)
Kereru 0 (2)
Long-tailed cuckoo 12 (15)
Shining cuckoo 2 (1)
Black-billed gull 0 (1)
Black shag 0 (1)
New Zealand falcon 2 (0)
Kea 30 (18)
Kaka 14 (2)
Yellow-crowned parakeet 4 (37)
Rifleman 53 (184)
Rock wren 2 (1)
Tui 2 (0)
Bellbird 41 (33)
Grey warbler 21 (23)
Mohua 8 (42)
Brown creeper 13 (26)
Fantail 9 (23)
Tomtit 21 (96)
South Island robin 22 (1)
Silvereye 8 (105)
Song thrush 3 (1)
Blackbird 10 (2)
Dunnock 6 (6)
Pipit 3 (2)
Chaffinch 54 (38)
Redpoll 45 (62)
Yellowhammer 4 (5)

Nga mihi nui
Colin

[Adam C]

Im just impressed with the number of Long Tailed Cockoo. We're these birds seen or just heard?

[Colin Miskelly]

Hi Adam

Three seen and the others heard

C

[Adam C]

Also is the lack of Kereru normal down there?

[Davidthomas]

I’m intrigued by the severe reduction in both silver eye, rifleman and kakariki. Yet Kaka and Kea both have increased. You’d think they’d all be in the same boat (minus silvereyes)

[andrewcrossland]

I think Kereru are pretty rare in Beech Forest full stop aren't they? I did some contract surveys along a bunch of transect lines in the Craigieburn Forests and the eastern side of Arthur's Pass National Park in Oct/Nov 2015 and again in 2017 and pretty much saw zero Kereru amongst many thousands of other species records.

[Ian Southey]

Pigeons can do OK in Silver Beech forest, certainly in the south where common foods are beech strawberries and foliage, especially Asplenium flaccidum. Sometimes you see them in the understorey eating Coprosma fruits but with fruiting and flowering species mostly removed by deer you have to wonder if they have been a game changer for these birds, especially in Red and Mountain Beech forests. They also flock to Kowhai in spring to eat both leaves and flowers and the Dart bridge was a good place to see them but these areas are often farmland now and those trees are all old and presumably have a finite lifespan.

Since at least the 1990s the upper Wakatipu basin has been a very good place for Falcons, perhaps a national hot spot. They have also probably benefited from predator control as they are ground nesters in southern forests and I have known them to have trouble in stoat plague years.

Looking at the numbers of Robins, Kea and Kaka I suspect predator control (traps and aerial 1080) in the Dart catchment as it was very good, at least up to about 15 years ago. The low numbers of Yellowheads and parakeets are a bit of a puzzle. It used to be possible to find more of each within a few hundred metres of the Routeburn carpark. Across the river on the track itself there were fewer Yellowheads but they certainly were there. In early January they might have started to flock but that usually means it takes longer to find them. Before christmas they should be dispersed and feeding chicks. Maybe the scarcity of small birds suggests a bad winter for food. Certainly it was unusually wet here in Auckland and after a brief respite turned wet and cloudy again. Numbers of birds like Fantails and Riflemen can fluctuate quite a lot from year to year, general consensus was weather and that might be true - but not tested I think.

Ian

[Jim_j]

I suspect that our endemic hole nesters also roost in holes at night - I think this was flagged in an article in Notornis for yellowhead a few years ago.
I kept kakariki for a number of years and they also spent the night in nest boxes.
This behaviour would certainly have made sense in a land with no mammal predators hunting by sense of smell.

If this is correct rats will eventually eradicate these birds no matter how often 1080 is used - and quite possibly supressing stoats to low levels actually accentuates the problem outside of mast years.
You only need to look a Stewat island where mohua and eventually Rifleman and the smaller y/c parakeet have been eliminated from the main island in the presence of rats alone.
Cheers Jim

[Jan]

The lack of small bird species is mainly down to rats, I've always understood. If mostly stoat trapping is being done [as it was when I last walked the Milford a few years ago and was told about Air NZ's involvement in predator control], then rats will proliferate unless enough 1080 drops are done. And 1080 is so hated by the public, with influential people like Steffan Browning still disputing the level in water courses, I can't see there's any bright future, not no way......