Colour-banding of bellbirds in the Port Hills – a research project in association with Christchurch City Council
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Landcare Research and the Park Rangers of Christchurch City Council have been working together to place colour-bands on bellbirds and then resight these birds at a later time to determine their movements. Photograph: Scott Butcher |
INTRODUCTION & AIMS
Many of the questions we need to answer centre around the distances that bellbirds travel to feed, the times of the year that they travel, and the food sources that they use. Much of this information needs to be determined separately for male, female and juvenile birds, and to be tied to the location of the bird’s breeding territory. The usual method for collecting such information is by catching the birds in mist-nets and placing colour-bands on their legs. The sex, age and geographic banding location are recorded for each bird. When a bird is resighted it can easily be identified by the colour of the bands.
The colour-banding process was carried out by trained operators and took place under the following approvals:
- Manaaki Whenua—Landcare Research Animal Ethics Committee Approval, Project No. 01/03/06
- Department of Conservation Authority to Catch, Handle and Release Absolutely Protected Wildlife, Permit No. CHH 12/120
- Bird banding permit number 0294 (Canterbury passerine research group).
COLOUR-BANDING
Fifty-five bellbirds were individually colour-banded in the summer of 2001/02, and a further 18 in the summer of 2002/03.
| Colour-banded bellbirds, summers 2001/02 and 2002/2003 | Adult male | Adult female | Juvenile | Totals |
| Omahu Bush | 12 | 2 | 7 | 21 |
| Kennedy’s Bush | 17 | 7 | 1 | 25 |
| Victoria Park | 19 | 3 | 5 | 27 |
| Totals | 48 | 12 | 13 | 73 |
There are several reasons for the high number of males caught. The first is that females tend to stay relatively quiet and close to the nest during the breeding season, whereas a male is more likely to confront an intruder in the breeding territory. Also a number of the mist-netting locations were close to favoured food sources such as flowering flax and fuchsia, where males sometimes dominate and exclude females.
Each bird was banded with two bands on the left leg and two on the right. Three of these are coloured (red, yellow, blue, green or white) in a unique combination, and one is metal (carrying a unique number).
We intend to increase the number of bellbirds carrying bands over the next few summers. Currently the percentage of the population carrying bands is probably only around 5 to 7%.
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A mist-net being set up. Photograph: Scott Butcher When a mist-net is set up in the shade under tree canopies, it is very difficult for birds to see, so they can fly into it. The net has loose pouches where the birds are caught. The netting is very fine and soft so that it does not harm the bird. The bird is extracted very gently by a skilled operator. |
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Colour-banding a bellbird. Photographs: Andrew Crossland The bellbird is supported in the correct way with its head between the operator’s fingers. Colour-bands of specified size (from the DOC banding office) are placed on the legs. The colour combination of the bands is written down, as is the unique number on the metal band. The bird is weighed, and its weight and sex is recorded beside the band colour-combination and metal band number. |
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RESIGHTING
The percentage of the bellbird population carrying bands is still low, but we have begun resighting studies to refine our methods and acquire some initial data. Our aims are to find out:
- Which segments of the population (male/female/juvenile, and birds from different Port Hills valleys) are travelling down to Christchurch city to feed in the winter
- How far and when birds travel from the Port Hills
- Whether young birds always return to breed near the site where they were raised.
The bands will also help us determine:
- How big a single breeding territory is in different vegetation types
- How far the male and the female of a pair travel to forage during the breeding season – though we will probably also approach this question using radio tracking.
So far, we have carried out a resighting study in Christchurch city and the Port Hills in late August/early September 2002, and have also recorded some recaptures in the Port Hills during the summer banding period of 2002/03. Though it would be premature to draw definite conclusions as yet, it appears that bellbirds remain in (or return to) the same Port Hills Valleys from year to year. Most resightings have been in very close proximity to the location at which the bird was banded.
If you are looking out for banded bellbirds, a strong pair of binoculars is useful, as it can be very difficult to identify the band colours with the naked eye. The convention is to read the bands in the following order – upper band on left leg, lower band on left leg, upper band on right leg, lower band on right leg. You can expect to see three colour bands (selected from red, yellow, blue, green and white) and a metal band. We would welcome any reports of colour-band sightings on our observation webpage.